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.45 Auto Rim +P Loads

B

BUFF

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The new issue (February 2017) of HANDLOADER magazine has an article by Brian Pearce about loading the .45 Auto Rim to Plus-P velocities/pressures. Pretty good range of bullets and powders used.

I found it to be interesting in that he lumps the Colt and S&W 1917 revolvers in with newer guns like the 1950 and 1955 Targets as suitable for the higher pressure rounds. I have never used anything hotter than standard .45 ACP ball or equivalent in the 1917.
 
Is there some problem with the standard loading that this solves?
Did he do pressure testing? I assume he used the +P pressure of the .45 Auto round, as I doubt SAAMI has a +P specification for the .45 Auto Rim.
In particular, if you EVER see any pressure sign in .45 Auto or .38 Spl, you are almost certainly well past any safe point. So, unless you have pressure testing equipment, why risk your gun or hand or body to loads that are over standard pressure?
 
I do not recall him writing about where he gets his pressure measurements, but from the way he breaks his loads down by pressure in some articles, he sounds like he has access to pressure testing gear.

Factory loaded Auto Rim as loaded by Remington, the last big loader of the round (not to include the 'boutique' loaders like Buffalo Bore) didn't load it to even full .45 ACP pressure and velocity levels. A lot of folks always are reaching for just a little bit more velocity, to improve bullet expansion in game or flatten out their trajectory a smidge to account forma range estimate that was off a little. My Auto Rim handloads have, for years mebbe decades, either duplicated .45 ACP factory loads or, for more thump, traditional .45 Colt factory loads, with a cast 255 grain SWC bullet over enough Unique to give me 875 fps. The latter load showed no pressure signs at all.
 
I limit my 1917 loads to the low end of the spectrum. I see no reason to push the limits on them. While the 1917 isn't an antique built for black powder or anything like that, the cylinder walls are real thin and i'm guessing the heat treatment processes during WW1 weren't quite the same as post WW2.

I'm sure shooting +P loads won't blow up a gun, but the additional wear and tear will add up pretty quickly if shooting box after box of ammo through them. If I could go back in time and scoop up a couple 1917's for cheap I might be interested in pushing one of them to the limits but they are going for $500 and up now a days.
 
I went downstairs and pulled the SAAMI pressure document I have. Much to my surprise there is a .45 ACP +P listing-but only in the piezo-electric system list.

So, from the list, .45 both ACP and Colt have a standard Maximum Average Pressure of 14, 000 psi. .45 ACP +P is listed with a MAP of 24,000 psi. There is no SAAMI authorized +P listing for .45 Colt.

That said, even if I felt like doing +P in .45, remember the S&W admonition not to use +P in any pistol not having a model number. Model of 1917 doesn't count. The conversion to model numbers instead of names was about 1958 or so. The real problem area on the S&W cylinders is the bottom of the cylinder stop notches. Things can get really, really thin there.

Since you're looking at potentially better than 50% pressure increase (just because that's the limit doesn't mean any factory loaded ammo reaches that limit), I wouldn't use that ammo in anything that isn't recent production. I'm real sure that if you read all the fine print in that magazine there's a disclaimer of legal liability should you use any published loads. While the guy might well be a dedicated and scientifically sound researcher into loading data, I wouldn't stake my well being on any presumed expertise with regard to metallurgical properties. I think the opinion I noted above of S&W toward the use of +P has much more authority than the author/magazine.
 
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I realize a lot of people don't like to buy loading manuals, but, for years, Sierra has listed ".45 ACP revolver" loads. These are a good bit hotter than standard loads but presumably quite safe in quality revolvers that are in good condition.
 
WR Moore said:
I went downstairs and pulled the SAAMI pressure document I have. Much to my surprise there is a .45 ACP +P listing-but only in the piezo-electric system list.

So, from the list, .45 both ACP and Colt have a standard Maximum Average Pressure of 14, 000 psi. .45 ACP +P is listed with a MAP of 24,000 psi. There is no SAAMI authorized +P listing for .45 Colt.

That said, even if I felt like doing +P in .45, remember the S&W admonition not to use +P in any pistol not having a model number. Model of 1917 doesn't count. The conversion to model numbers instead of names was about 1958 or so. The real problem area on the S&W cylinders is the bottom of the cylinder stop notches. Things can get really, really thin there.

Since you're looking at potentially better than 50% pressure increase (just because that's the limit doesn't mean any factory loaded ammo reaches that limit), I wouldn't use that ammo in anything that isn't recent production. I'm real sure that if you read all the fine print in that magazine there's a disclaimer of legal liability should you use any published loads. While the guy might well be a dedicated and scientifically sound researcher into loading data, I wouldn't stake my well being on any presumed expertise with regard to metallurgical properties. I think the opinion I noted above of S&W toward the use of +P has much more authority than the author/magazine.
Click to expand...

You might want to recheck those SAAMI specs. .45 Colt MAP is 14,000 PSI, but .45 ACP is 21,000 PSI and .45 ACP +P is 23,000 PSI. This is direct from the SAAMI website.
 
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noylj said:
Is there some problem with the standard loading that this solves?
Did he do pressure testing?
I assume he used the +P pressure of the .45 Auto round, as I doubt SAAMI has a +P specification for the .45 Auto Rim...
So, unless you have pressure testing equipment, why risk your gun or hand or body to loads that are over standard pressure?
Click to expand...

Here we go again... :rolleyes:

You seem to fail to acknowledge that 45ACP rounds are also shot in revolvers that also chamber 45ARs.

45AR are 15K CUP (SAAMI). If you're happy with that level of performance from this round then this article is NOT for you.

Standard 45ACP is 18K CUP or 21K PSI (SAAMI).

(+P) 45ACP is 23K PSI.

45ACP cases have the same volume/capacity as 45AR cases; ~1.77cc/ml, or, ~27.3gr/H²O.

Any modern 45AR case can easily handle either of these 45ACP pressures, & more (S-L 45AR).

There's no reason you couldn't fire 21K PSI loads, either 45ACP or 45AR, in a 1917 in good repair.

All modern M25/625/325s are rated for (+P) loads, either in 45ACP or 45AR cases. No difference.

Much of the article's listed data is standard pressure, while the rest are +P, the same as listed by bullet & powder manufacturers.

As always, cross reference data between sources, if in doubt, but to say you shouldn't use a load if you/they don't have pressure testing equipment is silly, especially considering the nominal levels listed & how simply they can be corroborated.

Brian Pearce isn't known for being reckless, as far as I'm aware of.

.
 
You sure you read it right?
Sporting Arms and Ammunition Manufacturers' Institute PSI Recommendations

Handgun Max, psi
25 Auto 25,000
32 S&W Long 15,000
380 Auto 21,500
9mm Luger 35,000
9mm Luger +P 38,500
38 S&W 14,500
38 Auto 26,500
38 Special 17,000
38 Special +P 18,500
38 Super Auto +P 36,500
357 Sig 40,000
357 Magnum 35,000
357 Remington Max 40,000
40 S&W 35,000
10mm Auto 37,500
41 Remington Mag 35,000
44 Special 15,500
44 Remington Mag 36,000
45 Auto 21,000
45 Auto + P 23,000
45 Long Colt 14,000
454 Casull 65,000
480 Ruger 48,000
 
From this:
>Originally Posted by WR Moore
>So, from the list, .45 both ACP and Colt have a standard Maximum Average Pressure of 14, 000 psi. .45 ACP +P is listed with a MAP of 24,000 psi.
 
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