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Tales from the Back Creek Diary - A .45 ACP Rifle?

© 2014 - Ed Harris

(Click on photo for a larger pic…)

Beretta Model 412 Converted to a .45 ACP Rifle…

I like having at least one long gun capable of firing each caliber of handgun ammunition I keep around. Rifles chambered for center-fire handgun calibers provide greater kinetic energy than any rim-fire, but also have low noise, usually not needing a suppressor. The .45 ACP and .38 Special are my favorite cartridges for this, because standard pressure (non +P) loads are quiet when fired in a rifle, their report comparing to firing a .22 rifle. They also have sufficient energy to kill deer-sized game at short range and useful self-defense potential, while presenting a less threatening profile than a military-caliber EBR (Evil Black Rifle) so as "not to scare the natives."

The .38 Special and .45 ACP work best for such purposes because they are loaded with fast powders which burn completely in a barrel length of only 5-6 inches. Ordinary 158-gr. lead bullet .38 Special loads gain about 150 f.p.s. when comparing a 4 inch revolver to a 20 inch lever-action.  In .45 ACP the expansion ratio produced by firing from a rifle-length barrel, combined much greater bore contact area, hugely increases bore drag, which negates the effects of adiabatic expansion, so that little or no velocity gain is achieved when compared to firing the same ammunition from an M1911 pistol. Muzzle-exit pressure is very low so that the report compares to firing standard velocity .22 LR fired from a sporting rifle if barrel length is greater than 20 inches. The velocity of any common .45 ACP ammo is subsonic when fired from a rifle.  I don't try to see how fast I can load for handgun-caliber rifles; because assembling specialized “rifle ammo” which cannot be used in the handgun defeats the purpose. The combination of substantial bullet weight, adequate good accuracy and low noise is both pleasant and effective.

About 25 years ago Wayne Schwartz re-bored a Marlin 1894 in .44 Magnum to .45 ACP for me and this worked really well.  I let Wayne talk me out of the rifle when I left Ruger and regretted it ever since, so I've had another done.  This time I took a .45 Colt Cowboy II and sent it to John Taylor who set the .45 Colt barrel and magazine tube back, re-chambered the barrel, fitted a new extractor, and reworked the lifter.  It holds twelve rounds in the magazine tube, as finished with 22-1/2" barrel), is 39" overall and weighs 6 lbs.12 ozs.


I use this rifle mostly with Saeco #954 230-gr. lead FN  Cowboy slugs and 5 grs. of Bullseye, which gives about 1000 f.p.s. in the rifle, vs. 830 in an M1911 pistol and about 800 f.p.s. in my S&W Model 625 revolver.   Given the limited powder capacity and faster powders used in the .45 ACP you only get modest velocity gains in a longer at permissible chamber pressures (20,000 cup max.).   

The .45 ACP Marlin is not as accurate as my best loads in the .357 lever, but it meets my original intent as a fun camp gun and plinker. Shooting iron sights, I get 1-1/2" groups at 25 yards which stay in proportion to 100 yards.. The front sight covers a 6" gong at 100 yards. I've zeroed the gun to hit about 3" over the top of the front sight at 50 yards, and under the sight when I blot out the target at 100. Groups to 100 yards are about the same as an accurized M1911 hardball gun, but with the peep sights and longer sight radius it is must easier to ring the gong. With correct hold-over rings the 12" gong at 200 yards almost every time. The bullet's time of flight is long enough for the gun report to fade away as you hear the bullet strike "ding!" against the steel like the Scheutzen troll swinging his little ball peen hammer each time.

One of my favorite walking guns is a Beretta Model 412 folding shotgun for which I have .45 ACP, .357 Magnum, .44  Magnum, and .410 shotgun barrels. 


Firing the .45 ACP in the 26 inch rifle is a satisfying “blooper” which you can watch and hear a video of at this link:



Following table is compiled from my firing logs recorded over a period of more than 25 years. The Mk.IV Webley was originally a .455 which was converted to fire .45 ACP using moon clips in the 1960s. S&W 625 is a 1989 custom shop gun. M1911A1 is a 1967 National Match pistol, the Marlin is a converted 1894 Cowboy which was originally built in .45 Colt, having the barrel set back and re-chambered to .45 ACP, with the lifter and extractor reworked.  The 26 inch .45 ACP barrel was produced by John Taylor to fit onto my Beretta M412 folding shotgun.

.45 ACP Ctg___MkIVWebley4"___S&W625_4"_____M1911_5"_____Marlin22"_____Beretta26"



 WCC69 Ball---------not-fired--------799----------------832-------------not-fired-----844


 WCC84MatchBall----779-------------793----------------843------------ 872----------944









A .45 ACP rifle will not appeal to those whose concept of a satisfying firearm must make your shoulder hurt and ears ring.  If you enjoy being able to actually watch big bullets fly downrange and to be able to comfortably fire occasional rounds outdoors at varmints without ear protection, consider a rifle chambered for any common handgun caliber, firing subsonic cowboy loads.  They are out there and they are fun.   If you want gunsmith project, then build yours in .45 ACP.  

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