1911 Magazine Analysis: Part 2

[Frontpage]

[Introduction]

The very first firearms-related article I wrote dealt with 1911 magazines. That article examined how an eclectic selection of 1911 magazines interacted with the slidelock and fed ammo.

Although the prior analysis produced several interesting discoveries, it was more survey than exhaustive analysis. The magazines were treated as entire units; though this approach was appropriate for the the questions at hand, it raised more questions than it answered. Specifically, the dramatic differences observed between magazines with tapered and straight feed lips made me wonder which part of the results could be attributed to the feed lips as opposed to the shape of the follower. Furthermore, the last analysis only looked at ball ammo; would different bullet shapes such as hollowpoints or wadcutters make a difference?

There was only one way to find out, and you're reading its writeup.


http://230grain.com/images/articles/magazines2/tn_testbed2.jpg (http://230grain.com/images/articles/magazines2/testbed2.jpg)

Another casual look at magazines.

Unlike the previous analysis, I wasn't going to look at a wide range of magazines. The end result of all that variety was discovering that the most dramatic difference came from the shape of the magazine lips. This time around, the plan was to eliminate all variation except for the feed lips in order to see what difference the lips alone made. To do so, I'd have to find magazines that were structurally identical except for the lips. Fortunately, this is simple enough if you go with the original and still-ubiquitous seven-round design, which uses a welded baseplate, folded metal follower with a dimple on the top, and a strong (about 11 pounds) spring. This is the magazine John Browning designed to be part of the M1911 pistol.


http://230grain.com/images/articles/magazines2/tn_magpile.jpg (http://230grain.com/images/articles/magazines2/magpile.jpg)

A pile of old-school.


[USGI]

Well, sort of. Browning's blueprints call for long, tapered feed lips; magazines using this style of feedlips are known variously as "USGI", "hardball", or "ball-only" mags. For the purposes of brevity, this article will refer to the lip style and magazines featuring the lip style as "USGI".


http://230grain.com/images/articles/magazines2/tn_lips_comparison_top.jpg (http://230grain.com/images/articles/magazines2/lips_comparison_top.jpg)

Left: USGI-style fully-tapered feed lips.

USGI mags bear two conflicting reputations: They purportedly feed ball (i.e. full metal jacket) ammunition beautifully, but are said to choke horribly on hollowpoints or wadcutters. The latter reputation is the reason USGI magazines are in short supply nowadays: The 1911 rennaisance started with target guns feeding lead semi-wadcutters, a setup that for many Bullseye shooters caused an unacceptable number of aliases. This prompted modifications to the original design. At first, the tapered lips were "tuned" by gunsmiths to release rounds early by opening up the feed lips beyond a certain point; later, this was simplified to purely parallel feed lips with the desired early-release point. (More on both of these later.)

By the time the 1911 started seeing widespread acceptance as a defensive sidearm, the damage done to magazine design by its target-shooting era was done; USGI-style magazines were and still are vanishingly scarce. For a long time, the only source was military surplus, hoarded jealously by those who had them. Recently, though, magazine manufacturer Check-Mate started offering new tapered-lip 1911 magazines in blued and stainless finishes. This article will attempt to determine whether the reintroduction of the original design represents rediscovery of a classic technology prematurely tossed on the scrapheap of history, or whether it's merely a nod to nostalgia long since supplanted by superior alternatives.


[Hybrid]


http://230grain.com/images/articles/magazines2/tn_lips_comparison_top.jpg (http://230grain.com/images/articles/magazines2/lips_comparison_top.jpg)

Center: Colt-style hybrid feed lips.

As mentioned above, one of the first alternatives offered to the USGI design was tapered-lip magazines altered to release the round early. This modification preserved the initial taper, which let the round rise up as it was fed forward, but let the cartridge spring free of the magazine well before the same thing would occur with a full USGI taper. Although initially a modification, magazines came to be built with hybrid feed lips and Colt continues to use hybrids as its OEM mags for non-Gold Cup 1911s.


[Wadcutter]


http://230grain.com/images/articles/magazines2/tn_lips_comparison_top.jpg (http://230grain.com/images/articles/magazines2/lips_comparison_top.jpg)

Right: Parallel early-release "wadcutter" feed lips.

Ultimately, though, 1911 magazines would come to be dominated by short, parallel feed lips. These were the logical conclusion (some would say the reductio ad absurdum) of early-release tapered lips designed in pursuit of reliable feeding from wadcutters. As such, they're commonly referred to as "wadcutter" magazines or feed lips. Testing in my previous article had shown wadcutter mags feeding far less smoothly than hybrids, but that had been with ball ammo; would using actual wadcutters or short hollowpoints vindicate this design?

[Frontpage]

[The Ammo]



Out of the dizzying array of .45 ACP ammunition offered for sale, I selected what I hoped would provide a representative subset of the types of ammo one could expect to feed an unwitting 1911. There were multiple kinds of hollowpoints, lead semi-wadcutters, short jacketed wadcutters, truncated cones, and even two different kinds of ball ammo just in case it made any difference. (Sneak preview: It didn't.)


The purpose of all this variety was not merely exhaustively thorough overkill (although I do love overkill so very much); rather, I was interested in establishing the sensitivity of the 1911 design in general to minor variations in ogive, meplat, and cartridge length given various magazines' feed lip designs. In other words, it's possible to say that a few hundredths of an inch in length or a tiny taper shouldn't make any difference, but it's very hard to say for sure without trying a variety of bullet shapes.


So let's try a variety of bullet shapes.


[Speer Gold Dot]



http://230grain.com/images/articles/magazines2/tn_gd_box.jpg (http://230grain.com/images/articles/magazines2/gd_box.jpg)

230-grain Speer Gold Dot




First up is one of the most popular hollowpoint brands on the market, Speer's Gold Dots; no ammo test would be complete without them. In .45 ACP, these have a slightly rounded ogive and wide, flat mouth. I'd actually never fired Gold Dots in .45 ACP, so these rounds represented an unknown.


http://230grain.com/images/articles/magazines2/tn_gd_calipers.jpg (http://230grain.com/images/articles/magazines2/gd_calipers.jpg)

1.209 inches OAL




Gold Dots were one of the shorter hollowpoints tested.


[Federal HST]



http://230grain.com/images/articles/magazines2/tn_hst_box.jpg (http://230grain.com/images/articles/magazines2/hst_box.jpg)

230-grain Federal HST




Federal's HST is their law enforcement-targeted successor to the veneral Hydra-Shok round. Since I could not dig up any of the old-style Hydra-Shoks by the time of the test, this would have to be the next best thing. HSTs have been producing dramatic results in ballistic gelatin, so would their performance feeding into a 1911's chamber be equally good?


http://230grain.com/images/articles/magazines2/tn_hst_calipers.jpg (http://230grain.com/images/articles/magazines2/hst_calipers.jpg)

1.208 inches OAL




HSTs are the shortest hollowpoints tested, at a mere 1.208 inches.


[Winchester Ranger]



http://230grain.com/images/articles/magazines2/tn_ranger_box.jpg (http://230grain.com/images/articles/magazines2/ranger_box.jpg)

230-grain Winchester Ranger




Winchester Rangers are a popular hot-loaded hollowpoint whose razor-sharp petals inflict horrendous gashes on ballistic gel. I had fired these through my Mil-Spec with good reliability before and found their recoil brisk but controllable. With their scalloped edges, relatively long overall length for a hollowpoint, and curved profile, they raised the possibility of interesting feeding behavior when tested.


http://230grain.com/images/articles/magazines2/tn_ranger_calipers.jpg (http://230grain.com/images/articles/magazines2/ranger_calipers.jpg)

1.2145 inches OAL (last digit esimated)




Winchester Rangers are slightly longer than the sub-2.10-inch realm occupied by Gold Dots and HSTs, but are not nearly as long as Golden Sabers or ball ammo. (See below.)


[Remington Golden Saber]



http://230grain.com/images/articles/magazines2/tn_gs_box.jpg (http://230grain.com/images/articles/magazines2/gs_box.jpg)

230-grain Remington Golden Saber




It was with no small amount of self-interest that I selected Golden Sabers as one of the hollowpoints for the test. Golden Sabers happen to be my current 1911 carry ammo, which also makes it easy to dig up a box for testing. I'd always assumed that the relatively long overall length and rounded, ball-like profile meant these rounds enjoyed higher reliability than other hollowpoints, but had never been given the opportunity to test them against others to learn whether my assumptions were correct. Now was the perfect opportunity to do so.


http://230grain.com/images/articles/magazines2/tn_gs_calipers.jpg (http://230grain.com/images/articles/magazines2/gs_calipers.jpg)

1.2368 inches OAL (last digit estimated)




Golden Sabers are the longest of all the hollowpoints tested by a fair margin.


[PMC Ball]



http://230grain.com/images/articles/magazines2/tn_pmc_box.jpg (http://230grain.com/images/articles/magazines2/pmc_box.jpg)

PMC Bronze Line 230-grain full metal jacket




No 1911 ammunition and magazine analysis would be complete without good old ball ammo. 230 grains' worth of copper-clad round-nosed lead is a 1911 staple whose reliability few impugn. At the very least, it would provide a baseline against which to compare the behavior of various hollowpoints and exotically-shaped bullets. Hopefully, its long overall length would illuminate any differences in the way magazine lips fed.


http://230grain.com/images/articles/magazines2/tn_pmc_calipers.jpg (http://230grain.com/images/articles/magazines2/pmc_calipers.jpg)

1.258 inches OAL




Much longer than any of hollowpoint; would it matter?


[Winchester USA Ball]



http://230grain.com/images/articles/magazines2/tn_wwb_box.jpg (http://230grain.com/images/articles/magazines2/wwb_box.jpg)

Winchester "White Box" 230-grain ball ammo




Just to be thorough, I grabbed a second brand of full metal jacket. Commonly known as Winchester "White Box" (or WWB), Winchester's USA brand is a budget line commonly sold in 100-round value packs at Wal*Mart. It's an old favorite of mine that has always performed well. It got included in the testing because the shape of the bullet was visually different from the PMC ball ammo, so testing the two side-by-side could possibly reveal subtle differences. It was worth a shot, anyway.


http://230grain.com/images/articles/magazines2/tn_wwb_calipers.jpg (http://230grain.com/images/articles/magazines2/wwb_calipers.jpg)

1.266 inches OAL




Winchester's ball ammo is distinctly longer than PMC's, and the longest cartridge tested.


[Black Hills Lead Semi-Wadcutter]



http://230grain.com/images/articles/magazines2/tn_lswc_box.jpg (http://230grain.com/images/articles/magazines2/lswc_box.jpg)

200-grain lead semi-wadcutters




200-grain lead semi-wadcutter rounds have a long history in 1911s. They're lighter-recoiling than hardball rounds and punch clean holes in paper, making them popular with target shooters. However, the sharp shoulders and flat meplat produce a bullet radically different in shape than the round-nose ball ammo for which the 1911 was ostensibly designed. I was interested in finding out if this made any difference in feeding, and if these changes would illustrate the reasoning behind "wadcutter" style feed lips.


http://230grain.com/images/articles/magazines2/tn_lswc_calipers.jpg (http://230grain.com/images/articles/magazines2/lswc_calipers.jpg)

1.2497 inches OAL (last digit estimated)




In length, at least, the lead semi-wadcutter rounds had more in common with full metal jacket than hollowpoints.


[Hornady Full Metal Jacket Flat Point]



http://230grain.com/images/articles/magazines2/tn_fmjfp.jpg (http://230grain.com/images/articles/magazines2/fmjfp.jpg)

230-grain Hornady FMJ with a flat meplat




The last two candidates for testing aren't factory cartridges, per se, but component bullets with interesting shapes that I loaded into empty cases for testing purposes.


The first of these is Hornady's Full Metal Jacket Flat Point bullet, loaded to the length specified in Hornady's Handbook of Cartridge Reloading: Seventh Edition (http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=438424). This bullet is interesting because it's a full metal jacket with a truncated cone profile. Early hollowpoints used truncated cone shapes, but these were abandonded in favor of rounded ogives more closely mimicking the ball profile. Was this because truncated cones were unreliable or fed strangely? My curiosity was great enough to justify loading up some test rounds to find out.


http://230grain.com/images/articles/magazines2/tn_fmjfp_calipers.jpg (http://230grain.com/images/articles/magazines2/fmjfp_calipers.jpg)

1.2038 inches OAL (last digit estimated)




At only 1.2038 inches, the flat point cartridge was shorter than any of the actual hollowpoints.


[Hornady Full Metal Jacket Semi-Wadcutter]



http://230grain.com/images/articles/magazines2/tn_swc.jpg (http://230grain.com/images/articles/magazines2/swc.jpg)

185-grain FMJ semi-wadcutters




This was another unique bullet that I loaded up according to the Hornady Manual (http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=438424)'s specifications. I bought a bag of these strange-looking little 185-grain bullets in the interests of making a light target load. They showed subpar reliability out of wadcutter mags in my Mil-Spec, so I set them aside. This test provided a great opportunity to dig the box out of my spider-infested garage, reconstitute some dummy rounds, and figure out why exactly they hadn't fed well. With a bullet this short and uniquely shaped, the results were sure to be interesting.


http://230grain.com/images/articles/magazines2/tn_swc_calipers.jpg (http://230grain.com/images/articles/magazines2/swc_calipers.jpg)

1.138 inches OAL




The shortest of all the tested rounds measured a positively squatty 1.38 inches in overall length.


[Summary Table]



The following table summarizes the types of ammunition tested:

Manufacturer|Bullet|Type|Weight (gr.)|Length (in.)
Speer|Gold Dot|hollowpoint|230|1.209
Federal|HST|hollowpoint|230|1.208
Winchester|Ranger|hollowpoint|230|1.2145
Remington|Golden Saber|hollowpoint|230|1.2368
PMC|full metal jacket, round nose|ball|230|1.258
Winchester|full metal jacket, round nose|ball|230|1.2668
Black Hills|lead semi-wadcutter|wadcutter|200|1.2497
Hornady|full metal jacket flat point|ball|230|1.2038
Hornady|full metal jacket semi-wadcutter|wadcutter|185|1.138

With mags and ammo in hand, all that was required before testing could commence was to determine a methodology.

[Testbed]

One issue that bothered me with the last magazine analysis was the inconsistent angle of photography from shot to shot. The photos were taken by a hand-held camera while holding the 1911 with my other hand. Getting the slide into position and trying to keep it steady for a macro shot precluded consistency consistency; furthermore, it was an exercise in frustration made bearable only by the limited scope of the prior analysis. Three different magazine types time nine varieties of ammunition equals a real need to make things easy on myself.


http://230grain.com/images/articles/magazines2/tn_testbed.jpg (http://230grain.com/images/articles/magazines2/testbed.jpg)

The easy way.


The above photo shows the test setup. The 1911 is supported by a small vise and a tripod-mounted camera is aimed at the ejection port for an optimal view of the action. The butt of the gun sits atop a small piece of tape to ensure that it's lined up the same way for each shot. Two full-spectrum lamps and a flash with diffuser were required to properly light things; even so, the first set of photos, 150 in total, had to be discarded due to improper lighting and angle and all the photos taken again. (You may have heard the howls of frustration.)


The notepad visible in the above photo was used to keep track of what was being photographed. Another problem that I ran into while taking photos for the last article was the headache of trying to match up photos with the notes I'd taken of what had been photographed. This time around, I embedded that information in the photo sequence by writing down what was about to be photographed on the notepad and then snapping a picture of the pad.


http://230grain.com/images/articles/magazines2/tn_tracking.jpg (http://230grain.com/images/articles/magazines2/tracking.jpg)

A most informative photo.


[Safety First]

Two of the rounds tested used component bullets loaded into empty, unprimed cases; the remainder, though, were live rounds. Given that the entire point of these tests was to assess behavior when chambering, that meant that I'd be putting the gun into battery with live ammo repeatedly. Theoretically, enough caution would prevent accidents, but blind faith in one's own competance is found soley among the incompetant.


http://230grain.com/images/articles/magazines2/tn_safety_pin.jpg (http://230grain.com/images/articles/magazines2/safety_pin.jpg)

An incompetant firing pin.


In order to prevent any pesky 0.452-inch holes in things, I introduced an old firing pin to a slightly newer hacksaw. The truncated pin would fit into the firing pin channel and hold the firing pin stop in place, but was far too short to hit the primer.


[Gun]

As with the last set of magazine tests, a Springfield Armory Mil-Spec in stainless steel was used. This 1911, although it has some issues with respect to the slide/barrel clearance, is pretty much in spec where the frame and barrel ramps are concerned; magazine feeding would be represented under correct conditions.


http://230grain.com/images/articles/magazines2/tn_burlwood_butt.jpg (http://230grain.com/images/articles/magazines2/burlwood_butt.jpg)

Stainless Mil-Spec with burlwood grips.


In addition to its neutered firing pin, the recoil spring and guide were removed to permit incrementally positioning the slide for feeding.


[Controlled Feed]

Before getting into the details of the feeding tests performed, it's necessary to recap the principles of controlled feed. The 1911 (or any other semi-automatic handgun chambered in .45 ACP) has the unenviable task of feeding a short, fat round as reliably as possible. The cartridge to be fed has to sit at least partly below the bore axis in order to avoid interference with the cartridge being extracted and ejected. The wider the cartridge, the farther it has to move upwards during feeding. The problem of cartridge width is compounded by its relatively short length. Not only does the top round in the magazine have to move quite a ways up, but it has relatively little horizontal distance in which to do so.

There are two general approaches to feeding .45 ACP (or any other cartridge) reliably. One can make the chamber as easy a target as possible, move the top cartridge in the magazine as high up as possible, and use the forward travel of the slide to fling the cartridge into the chamber. Glocks in all calibers represent the perfection of this technique and even some 1911 magazines attempt to replicate it to work around bad feed geometry. Uncontrolled feed works well enough that many guns use it, but this uncontrolled feed has its drawbacks: It's highly dependent on slide inertia relative to magazine spring strength and it introduces a large element of kinetically-sensitive randomness into the feed cycle. Although usually not a problem, uncontrolled feed can produce maddeningly random and unrepeatable errors followed by thousands of rounds of perfectly reliable performance. On the other hand, it's fairly easy to make relatively reliable uncontrolled-feed handguns: By definition, the tolerances are generous and forgiving.

Controlled-feed firearms take the opposite approach, pursuing reliability through predictability. The 1911 epitomizes this approach. Rather than type up a blow-by-blow description of what goes on during 1911 feeding, I recommend you read this writeup (http://forum.m1911.org/showthread.php?t=9178) for details. It's a complicated read, but worth the time. Controlled feed relies on precise relationships between all parts and involved. Failing to meet specifications can cause controlled feed to devolve into uncontrolled feed or, in the worst case, make a controlled-feed handgun jam in ways uncontrolled feed would not. The only advantage to an out-of-spec controlled-feed system is that failures are usually repeatable, which makes them easier to diagnose. But when the specified dimensions are met, there's only one variable in a controlled-feed system: the magazine.

[Chart]

To demonstrate how the magazines and ammo influence controlled feed, each combination of cartridge and mag was photographed at four critical points in the controlled feed cycle:


Cartridge in magazine, breech face just making contact with base of round
Cartridge still in magazine, bullet just touching the frame ramp
Bullet nosing over the barrel ramp, rim beginning to engage extractor
Bullet entering chamber during cartridge nose-over


These stages are shown in order left to right for each type of magazine feed lip. The pictures' row labels of "wadcutter," "hybrid," and "usgi" refer to short parallel feed lips, tapered lips with an early release, and fully-tapered lips, respectively. Finally, everything's grouped by ammo type.

All photos may be clicked for a clearer view.

[Frontpage]

Type|Result
Ranger|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_ranger_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_ranger_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_ranger_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_ranger_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/ranger_usgi_chamber.jpg)

Gold Dot|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_gd_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_gd_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_gd_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gd_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/gd_usgi_chamber.jpg)

Golden Saber|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_gs_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_gs_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_gs_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_gs_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/gs_usgi_chamber.jpg)

HST|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_hst_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_hst_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_hst_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_hst_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/hst_usgi_chamber.jpg)

Winchester ball|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_wwb_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_wwb_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_wwb_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_wwb_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/wwb_usgi_chamber.jpg)

PMC ball|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_pmc_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_pmc_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_pmc_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_pmc_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/pmc_usgi_chamber.jpg)

lead semi-wadcutter|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_lswc_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_lswc_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_lswc_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_lswc_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/lswc_usgi_chamber.jpg)

full metal jacket semi-wadcutter|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_swc_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_swc_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_swc_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_swc_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/swc_usgi_chamber.jpg)

full metal jacket flat point|wadcutter|http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_wc_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_wc_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_wc_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_wc_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_wc_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_wc_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_wc_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_wc_chamber.jpg)
hybrid|http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_hybrid_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_hybrid_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_hybrid_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_hybrid_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_hybrid_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_hybrid_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_hybrid_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_hybrid_chamber.jpg)
usgi|http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_usgi_mag.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_usgi_mag.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_usgi_frame.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_usgi_frame.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_usgi_barrel.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_usgi_barrel.jpg)http://230grain.com/images/articles/magazines2/angle1/x_fmjfp_usgi_chamber.jpg (http://230grain.com/images/articles/magazines2/angle1/fmjfp_usgi_chamber.jpg)

[Frontpage]

[The Wadcutter Question]

Taking photos initially left me even more perplexed about why short, parallel feed lips came into vogue. The photos show wadcutters benefitting from fully-tapered feed lips; in fact, everything seemed to do better out of USGI style magazines. The long taper let the cartridges rise up gradually, which brought a smaller section of the bullet's nose in contact with the frame ramp and minimized the influence of meplat geometry on the feeding process. Lifting the round higher also meant the cartridge's angle upon entering the chamber was a lot less dramatic. Why would anybody want to mess with success like this?

The answer didn't come until I hit the range with the magazines and a selection of ammunition. Shooting FMJ ammunition through the USGI magazines was an amazing experience (see below), but I encountered a jam when loading the same magazine with Golden Sabers. A live round was chambered, but another cartridge double-fed into its base.

Here's what I think happened. Under recoil, all cartridges walk forward in the magazine due to their inertia holding them in place as the gun snaps backward. When the magazine has tapered feed lips, "forward" also means "up" for the round on top. Golden Sabers have the longest overall length of all the hollowpoints tested, but they're still notably shorter than the shortest ball ammo examined. This lets the shorter cartridges rise forward and up far enough to slip free of the lips when the slide slams back. Because the GI feed lips keep control of the cartridge longer than other designs, this must let it move far enough so that when jarred loose it just hops into the chamber.

This problem wouldn't happen with parallel feed lips becaue they keep cartridges at the same height even if they walk forward. Provided the round is longe enough that it can't escape the feed lips, normal extractor engagement will occur.

That left just one question: What's to stop hybrid feed lip magazines from encountering the same problem as the full-taper mags? Hybrids sport the same taper initially; however, they release early. The same problem of a round rising high enough to escape could still occur, but the escaping round might not be far enough forward to guarantee landing in the chamber, and thus could pop out of the feed lips and escape the ejection port, leaving the next round down to chamber normally. This finally explained something I'd seen before: the occasional live round in the pile of spent brass.

The mystery of the wadcutter lips had been answered to my satisfaction. Short, parallel feed lips are a way to avoid doublefeeds when using cartridges with short overall lengths.

However, shortly after publishing the above account, I received a PM from a fellow on the M1991.org forums with the handle 1944Colt, who pointed out some problems with my explanation of the feed failures, forcing a revision of the above text. He also offered his recollection of the transition to wadcutter feed lips from USGI magazines, which makes a lot more sense than my earlier conclusions, especially in light of some old photos I turned up.


First, take a look at a cartridge being fed from a magazine with USGI feed lips:


http://230grain.com/images/articles/magazines2/tn_gi_feed_1.jpg (http://230grain.com/images/articles/magazines2/gi_feed_1.jpg)

Cartridge fully seated in USGI magazine.




http://230grain.com/images/articles/magazines2/tn_gi_feed_2.jpg (http://230grain.com/images/articles/magazines2/gi_feed_2.jpg)

Cartridge moving forward and canting up.




http://230grain.com/images/articles/magazines2/tn_gi_feed_3.jpg (http://230grain.com/images/articles/magazines2/gi_feed_3.jpg)

Note the high angle at this point in feeding.




Per 1944Colt, when wadcutters were introduced to guns using GI mags, they would end up tilting upward while still being controlled by the lips. Because the cartridge was shorter, it would jam into the barrel hood and lock up the gun. Moving to wadcutter lips changed the feed to look more like this:


http://230grain.com/images/articles/magazines2/tn_wc_feed_1.jpg (http://230grain.com/images/articles/magazines2/wc_feed_1.jpg)

Cartridge fully seated in wadcutter magazine.




http://230grain.com/images/articles/magazines2/tn_wc_feed_2.jpg (http://230grain.com/images/articles/magazines2/wc_feed_2.jpg)

Cartridge starting to move. Note low angle.




http://230grain.com/images/articles/magazines2/tn_wc_feed_3.jpg (http://230grain.com/images/articles/magazines2/wc_feed_3.jpg)

Cartridge continues to feed, but the angle stays consistent.


By the time this magazine lets the round tilt up and escape, its nose will be well into the chamber and it will be (hopefully) too late for a wadcutter to jam up the gun.

This makes a lot of sense, which it should: 1944Colt was there to see the transition. So many thanks to him for pointing me in the right direction and providing a historically correct explanation to supplement my own theory.



[A Magical Combo]

My favorite discovery to come out of this whole experiment was the performance of USGI feed lips with ball ammo. The rounded profile of FMJ bullets works perfectly with the angles of the full-length feed lips to produce an unbelievably smooth feed. Chambering a round feels like you're dropping the slide on an empty chamber.

Even better, control over the cartridge is absolute. When taking photos, I discovered that it was impossible to push the slide forward slowly enough to misfeed the round. Momentum was never a part of feeding, so the entire process is controlled solely by geometry. To put it another way, the slide can be under-lubed, undersprung, or just plain dirty, but as long as it is physically capable of returning to battery, it will not jam. This is pretty much the Platonic ideal of controlled feed principles--which is only appropriate, seeing as how John Browning wrote the book on controlled feed in handguns.

Such well-controlled feeding produced one unanticipated side-effect: My groups shrank when using ball ammo in USGI mags. The cartridges were making it to the chamber with enough reproducibility in their motion that it knocked a healthy 25% off my group sizes. I refused to believe it until after I'd gone back and forth between magazines several times, but it was there.

As a result of my experience testing the USGI-style feed lips, I've decided to change my carry ammo from Golden Sabers in hybrid feed lip magaziness to ball ammo in USGI mags. The terminal ballistics may not be as good, but I'll gladly surrender that for the feed reliability and accuracy improvements demonstrated by this classic cartridge/magazine combo.


[Monotony of the Modern Hollowpoint]

I went to some effort to photograph a variety of self-defense hollowpoints, but for the most part there was very little difference in the way they fed.

In retrospect, this is hardly surprising. All of the hollowpoints are designed to feed reliably in handguns and expand on impact. These design constraints guarantee that when independent companies try to maximize the reliability of both feeding and expansion, the results will be fairly similar. There's also the fact that the 1911's feed design, when correctly implemented, acts to minimize variations in bullet shape and length.

In the end, the photography showed how differences in feed lip geometry affected cartridge chambering under ideal conditions, but only range testing showed that the interior of an operating firearm is not an ideal place to be. Should I ever accumulate the masochistic tendencies required to do another analysis of this type, it needs to look at feeding of cartridges that have migrated forward under recoil.

Until then, I hope this article is useful as-is.


(c) 2009 C. Kaukl - All Rights Reserved. http://how-i-did-it.org (http://how-i-did-it.org/magazines2/)
Reprinted with permission.