Avoiding Rimlock in the .32 ACP

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Outpost75
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Joined: Fri Sep 11, 2015 3:50 pm

Avoiding Rimlock in the .32 ACP

Postby Outpost75 » Sun Sep 13, 2015 10:45 pm

Rimlock is caused by short-nosed bullets assembled into cartridges resulting in an overall cartridge length of less than 0.955". If you use bullets of a proper profile and correct overall length to prevent longitudinal shift of rounds in the magazine during recoil, rimlock cannot occur.

A solution some have suggested is shortening the length of the magazine box. This was done in the Seecamp pistol to enhance feeding with the 71-grain Winchester Silvertip, for which it was designed. However, doing so precludes the use of the most effective European 74-grain FMJ loads from RWS, Geco, Syntox, Sellier & Bellot, Sako, Norma, Lapua and Fiocchi, and I feel that limiting a carry pistol to only one type of ammunition is a glaring mistake in design.

In my experience light weight expanding bullets in the .32 ACP are less effective than FMJ.

First, the recoil impulse of lighter bullet loads is reduced and may impair function, especially in the older WW2-era and earlier pistols. Their flat-nosed shape feeds less reliably. Furthermore, if the the bullet IS fragile enough to expand, penetration is reduced, to only 7-11" in bare gelatin, which may be insufficient to reach vital organs if a sternum, rib or defensively positioned arm is hit, or if the threat is wearing heavy winter clothing. When JHP bullets don't expand, as typically happens when fired from barrels shorter than 3", the crush cavity produced in soft targets is inferior to full power Euro 74-grain hardball, which typically flips 180 degrees and continues base first, penetrating 12-14".

FMJ hardball is THE ammunition around which most .32 ACP handguns were designed. I tested WW2 German, Geco steel cased, Berdan primed 7.65 Browning (aka. 32 ACP) ammo from the estate of a WW2 vet. Despite age, all rounds went bang. All hit the 6" gongs on the dueling tree at 10 metres. Velocities were "hot and uniform" and would have been more effective than today's wimpy "lawyer" ammo. WW2 German issue ammo was loaded with a 5 gram (77- grain) gilding metal-clad steel jacketed bullet. The samples indeed attracted a magnet. Velocity from the Nazi-marked CZ27 pistol with 3.9" barrel the ammunition was packed with, was 981 fps, 17Sd over an 8 shot string. The same ammo fired from my Beretta Tomcat with 2.4" barrel gave 907 fps, 14 Sd, which compares closely to modern RWS, Selier & Bellot or Fiocchi 73-grain FMJ hardball, but does so with a somewhat heavier 77-grain bullet.

My hunting buddy “ER Doc” says that over his years, first as a military physician, and in the years since as a practicing trauma surgeon and pathologist in a major US city with an impressive rate of gun crime, many people have come across his operating table who have been shot with .32 ACPs. He says that FMJ ball rounds "typically flip 180 degrees after 5-6" of penetration, then continue base-first, often bouncing around inside the body cavity like a billiard ball" before stopping and do damage "out of proportion to their kinetic energy."
http://mousegunaddict.blogspot.com/2012/11/clear-gel-terminal-testing-sellier.html

Light recoil permits controlled "burst on target," making well placed double or triple taps possible in 2 secs. or so. This is EXACTLY the way European intelligence services and police organizations were trained from pre WW2 era until about 1972, when the Munich Olympic attacks prompted most European police agencies to adopt 9mm handguns. Until faced with multiple suicidal terrorists armed with automatic weapons, Europeans felt the .32 ACP was entirely adequate for covert ops, routine police work and self defense.

Modern light weight hollow-points tend to be a “jam-o-matic” in many guns. Of the currently available rounds only the Corbon and Fiocchi Extrema expand reliably when fired from barrels shorter than 3”. While a .32 ACP is not your first choice when expecting a fight, many people do carry them as deep cover backup, when a larger firearm is inconvenient, if the alternative is going unarmed. If you choose to carry a .32 ACP as your "country club and church gun" ER Doc says that "when you really need one, ANY gun beats NO gun at all!" He says that "100% reliable feeding, combined with accurate multiple hits, using deep penetrating Euro hardball is MUCH better than JHPs, which neither expand, nor tumble nor penetrate to the far ribcage with enough energy to bounce around......."

American .32 ACP ammo seems a universally an inferior breed of cat to Euro stuff and usually fails to reach 900 fps from short barrels, regardless of bullet weight and despite catalog claims to the contrary. The 75-grain Buffalo Bore hardcast flatpoint seems the one notable exception! "a full inch of denim and it still had enough uumph to plow though the SIM-TEST block 14.5" before escaping out the side of the block." http://mousegunaddict.blogspot.com/2012/06/buffalo-bore-32-acp-75-grain-hcfn.html

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