Warm .45 Auto Rim loads?


April 8, 2006, 01:00 AM
Okay, I've heard a few folks on here discussing the potency of .45 Auto Rim. I've heard some say they like to use warm .45AR reloads in a 625 revolver as a woods caliber.

So how hot can you go with it safely? I'm referring here to my gun, a 2004-5 production 5" 625. Obviously, you'll want to tone it down for pre-Second World War vintage guns, and possibly even guns that pre-date S&W's 1990s "endurance package" upgrades.

I know the modern 625 is a tough gun. They convert them to .460 Rowland, and I plan on running some .45 Super through mine one of these days. So what can you do with .45 Auto Rim?

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April 8, 2006, 01:09 AM
255-270 Keith SWC at 1000-1100fps.


April 8, 2006, 03:11 PM
I think a key consideration here is the case strength itself, less so than the revolver. In some loading manuals you'll find hot loads specifically listed for Ruger Blackhawks and Thomson/Center Contenders for that reason. The old .45 Colt, for example, can go WAY beyond what it was originally designed for, but the brass itself has to be respected. I don't think anybody makes a 'plus p' version of 45AR. I use a 625 myself, and yep, it's a stout firearm, but I stick with the high end of .45ACP to stay safe. The previous post indicates a beefy load I'd be comfortable with in mine, but I wouldn't want to push my luck much further. I just switch to my 629 when I desire more 'bang.'

April 8, 2006, 03:34 PM
You can safely use data for the .45 Super, .451 Detonic/460 Rowland, case strength is a MUTE point sice you are useing the revolver platform which fully supports the brass/gasket.

April 9, 2006, 06:53 AM
Moot not mute:what: :D

Johnny Guest
April 11, 2006, 10:23 AM
The .45 Auto Rim cartridge is SAAMI rated at 15000 c.u.p. max pressure. The .45 ACP is rated at 21000 p.s.i.

The ACP and AR cases are so nearly identical that I would certainly be comfortable in shooting any ACP load published in reputable manuals in a modern ACP revolver.

A post above mentioned, "[i]255-270 Keith SWC at 1000-1100fps" - - I'd be very cautious of seeking a load to reach that level, because of case volume limitations. If you feel it necessary to go this high, I strongly urge that you APPROACH FROM WELL BELOW and work up cautiously.

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road board, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

My heaviest load in .45 AR thus far: My old Lyman/Ideal #454424 mould is cut a bit long and drops fairly hard bullets at 276 gr. I load these over 6.0 gr. of Unique and they average 840 fps from a 1917 S&W with standard 5-1/2" barrel. This is where I gave up on trying to get any more from this near-90 year old revolver, and I don't feed it a steady diet of these loads. If I still owned a Model 25, I MIGHT oouch up a bit. Or not. This is about the velocity of a .45 ACP hardball load, with a 46 grain heavier bullet and a big flat meplat. I may one day take short range deer or small wild hog with this load. If I feel the need of any more power, I'll use a .41 mag, .45 Colt, or .44.

My 1917 is in excellent condition, very tight, and handles my heavy load nicely. It is the product of an elder day, though. I'm certain it cannot be as strong as a 21st Century M25. Your old 1917 may not tolerate the load well.


April 11, 2006, 11:10 AM
In Elmer Keith's book "Sixguns" he gives his load for the .45 AR as [REMOVED BY MODERATOR] of Unique behind a 250 grain bullet, sized .454. This was given with the caveat of its being used in S&W and Colt revolvers in good condition. I don't recommend its use in the Webley as the Webley isn't proofed for the pressures this load generates. I'm sure the modern Ruger sixguns would handle this load and more.

Carl N. Brown
April 11, 2006, 11:13 AM
Loading for a .455 Webley--.45 Auto Rim conversion,
I have found that .45 ACP brass tends to be more robust
than .45 AutoRim brass: cases swell more significantly
with .45 AutoRim than with .45 ACP with the same loads
and bullets, indicating to me that the .45 AutoRim case
walls are thinner or softer brass.

April 11, 2006, 12:19 PM

Bold experimenters over at handloads.com have demonstrated to their (and my) satisfaction that new production Starline .45 AR brass is stout stuff. I've gone as high as [REMOVED BY MODERATOR] under a 255 gr SWC for 1100 fps from a 4" 625, but only for experimentation and fun. As a more typical load, I like [REMOVED BY MODERATOR] under a 255 SWC for right at 900 fps from the same gun. If I need more than that, a bigbore mag is probly in order.

April 11, 2006, 06:24 PM
The CIP max. average pressure for the 45 Auto Rim is about 17,400psi. I would respect this as the absolute max for S&W 1917's in excellent condition. This gives up 875-900fps with a 260 grain Keith (454424).

Model 25's and 625's are made to take 45 ACP. The SAAMI max. average pressure for the 45 ACP is 21,000psi. If I don't mind feeding the revolver factory 45 ACP loads, then there is no reason not to load the 45 Auto Rim to that pressure. Depending on the exact bullet 950-975fps about where you hit this limit.

Increasing pressure to to the +P standard only gets another 25fps. What really helps is increasing effective case capacity by selecting proper bullets.
Longer, heavier nose with less bullet taking up powder room can buy you an addition 75-100fps at 23,000psi.

The Sierra Manual Fifth Ed. list loads for 45 ACP revolvers including the S&W's. I've never tested any of the loads from the book, but I don't doubt that some of them exceed 28,000psi. This is the area of 45 Super loads. I don't see a problem with pressures in this range for recent S&W's. Before I parted with my pre-endurance package 625, I put a few thousand 45 Super loads through it. With heavy bullets you run out of room for the slower powders at this point.

Nightcrawler mentioned the 460 Rowland conversion. This is way beyond my comfort zone, but it does show that 45 Super loads with 40% less peak pressure aren't going to damage the cylinder of a 625.


April 30, 2006, 04:26 PM
Found this thread on big boolits in .45 AR, and how high is maximum in this type.

I've toying with the idea of loading some .45 AR with 255 grain to 265 grain #452424 cast boolits. However, I'm not interested in maximum loads as I shoot most of this stuff in an old 1937 Brazilian S&W revolver.

Once read in Handloader magazine that Ross feller, (no longer associated with that pub.) had touted the .455 cartridge into being a nice old cartridge with modern powder used in a Triple lock and Webley. Something like 265 grain bullet with 3.9 or 4.1 grains of Titegroup powder giving a little over 620 fps velocity. Then he claims it shot to POA and made a 6 inch group at 100 yards. This feller been hanging around Elmer too long in his younger days. :D

Now I was wondering why not apply that loading in an .45 AR brass and have the bullet sized to .452 diameter instead of .454 or .455 diameter.

Titegroup has been a good powder in some of my loads and very accurate as it doesn't seem so case sensitive as others.

BTW, that #452424 265 grain bullet does not take up a lot of room in the brass.


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