45 ACP/45AR

jrplourde · Nov 12, 2009

I was reading the data in Spear #8 (1970) reloading manual and the question comes up re the strength of the acp re the ar. It has been stated in a recent post that they are identical.

The load data in Spear #8 is:
240gr lead/8.0 gr Unique max in the AR
230 gr lead/7.0 gr Unique max in the ACP
The manual mentions nothing about pressure.
Compare that with more recent manuals!!!!!

I rather suspect the difference is the application, revolver vs semi-auto rather than shell strength.

If you shoot an ACP revolver and want more poot this sure will put more lead in you pencil.

Bob

Dan Cash · Nov 12, 2009

7 or 8 grains of Unique with the bullets indicated would be quite a hand full. I find that 6-6.2 grains of Unique and a 225 grain cast bullet gives 875 +- fps from auto or 1917 with either cartridge case. Enough for me.

Jack Flash · Nov 12, 2009

Those loads are considerably higher than what is listed in Speer #14. I imagine the formulation for Unique may have changed over the years.

I think either case can handle the max pressure SAAMI gives for .45 ACP. Speer may have reduced these loads for lead bullets due to complaints about leading. I notice they have more powder in the loads they list for Unique/230 gr. jacketed bullets in #14, but still not up to the levels you quote from #8.

Gun 4 Fun · Nov 12, 2009

The ACP/AR issue does have a lot to do with if you are using the ACP in an auto, or a revo. Most 1911 platforms use throated barrels instead of ramped which support the entire case unlike the throated barrel.

Something that a lot of handloaders are not aware of is that alot of bullet manufacturers, who put out load data back then, did not have pressure guns for all, or even most of the calibers that they provided load data for. Some of the newer manuals that used pressure guns for the data, even mention that their new data supercedes all earlier data for that reason. An example is the Speer number 9 and 10. They state that while loads worked up in their Blackhawk for the .45 Colt were not pressure tested, they were safe in their test gun. It happened a lot back then. I know for a fact, that most companies didn't have, and most still don't have a pressure barrel for the .340 Weatherby, which is why the loads shown for it rarely look much better than the .338 Win.

Then too, we live in a law suit happy society now.....

Smithhound · Nov 12, 2009

Gun4Fun is dead on, most of the data published years ago relied on objective observations like flattened primers, sticky extractors etc. Modern electronics have changed alot of the load data. The M25 being a Target revolver, should be loaded with target loads, not driven to extreme.
A good substitute for it that you can push max with is the recent Ruger convertible .45acp/.45Colt, I have some really great loads with 185g JHP's that sizzle without any pressure signs. Of course the AR is a different fish but with the 625's it could be pushed upwards over what the old Target model would be comfortable with. Remember tho' that the case is the weak link in the mix not the firearm itself.
RD

Vulcan Bob · Nov 12, 2009

Yeah I tried some of the hot AR loads with a 255gr from the number eight. Holy recoil Batman and extraction was very hard and flattened primers as well. Needless to say I backed way off!

Tell Sackett · Nov 13, 2009

I have used loads from the Speer #8 in the 45AR for years. Are they stout? Yep! You don't have to shoot every round at maximum. As for the semi-auto/revolver comments, I'm not sure I want to beat my auto up with the recoil seeing as they are recoil operated. If you shoot those heavy loads in an auto you need to do some spring changing, in my opinion.

The M625 will take what you can dish out to it from just about any manual, even the Speer #8. It is the same frame/cylinder as the M629 with .009" thinner walls.

If you look at the Speer #6 manual though you will see that they had pressure testing equipment long before the #8. I would find it hard to believe that they didn't use it when they produced the latter manual. Didn't print it, I understand that, didn't use it, don't understand that.

p.s. I have use the SR4756 loads out of my 625. They clock out of my barrel at 1100fps with a 240gr bullet. Serious indeed!

Gun 4 Fun · Nov 13, 2009

As I posted, a lot of the bullet companies did not have pressure guns for a lot of the calibers they provided data for. Whether or not you want to believe it is up to you, but it's a fact, and that info has been published in various manuals over the years, not to mention countless handloading articles.
Tha various 25/625 designs are rated by S&W for +P loads that are running 23,000 PSI, which is a pretty stout load for sure.

I am curious as to where you came up with .009" difference. That is only half the difference in actuallity.

I measured several of my 25's and 29's at their thinnest point at the rear face of the cylinder. The .44 cylinder's average .075" outside wall thickness, with a stop notch depth of .035" ave. That leaves .040" at the thinnest point of the notch, and the weakest part of the cylinder.

Two of the 25, .45 cylinder's average .066" outside wall thickness at their thinnest point, with a stop notch depth of .040", while my 25-7 averages .045" stop notch depth. The first two leave a wall thickness of .026", and the other .021".

So if you average the three, at .024". That is .016" less steel over the case at the thinnest point in the 25 cylinder's than in the 29 cylinder's, and .018" less steel surrounding the case in the .45's than in the .44's, and that is a considerable difference. I agree that the rest of the guns are the same, but the cylinder is what contains the pressures.

Calaveras Slim · Nov 13, 2009

Tell Sackett and guns 4 fun are both way more knowledgeable than I am, for sure. I have never a big fan of bang to the wall handloads, so I can't comment on that kinda pressure.

Having sed that, I do like stout loads and for that reason, I am going to try a few loads out of #8 in 45AR and 44 special.

I let you know what happens when I get backfrom the hospital.

Gun 4 Fun · Nov 13, 2009

Cal Slim,

Don't misinterpret my post above. The 25/625 platform is a strong design, but we need to look at actual numbers when we are talking warmer loads than are listed in todays manuals. I regularly use 23,000 PSI loads in my 25's, and the cases pop right out. I just don't push them beyond that level to keep from causing excess wear to the guns, and to provide a large safety margin.

Tell Sackett · Nov 13, 2009

This seems to be a hot button issue for you. And I don't want to add fuel to an already burning fire but......................

As to the point of pressure equipment. While it may be true that some of the bullet manufacturersdidn't have pressure testing equipment, it isn't true for the company that produced the manual in question, Speer.
Here is a picture from their #8 that clearly shows their pressure testing equipment. It may not be "electronic", of that I'm not sure. Copper crusher stuff most likely. Nonetheless, they had it and it would be inconceivable that they wouldn't use a tool that they had so readily available. Take a look:

BBHFarm Gallery :: Speer #8, Speer Inc, 1970 :: aaj

As for the measurements, I just used the measurements of a SAAMI standard designed test barrel chamber. Case in point: 45ACP chamber measures .4796" at it's nominal measuring point. The 44Mag's chamber measures .4589" and if you subtract the two it gives you a .0207" difference. Of course you have to divide that by 2 to get how much material difference is left in a standard chamber, which gives you .01035", that's 10/1000". Sorry about the discrepency of .001" or so but I was looking at the test chamber of the 45AR round which measures .4789" thus giving the original measurement difference of .009". That is of course assuming that the centerline of the chambers is the same.

I think they are. Could be .001" wrong there too though.

Tell Sackett · Nov 13, 2009

Calvaras,

There are folks that have done 45WinMag conversions on M625's for years and the maximum pressure for that round is 40,000CUP according to SAAMI. I looked in their latest publication on the matter and they don't list a "PSI" rating for the 45WinMag so I can't tell you what that is. 40,000CUP though is the same rating for other magnum rounds, like the 44Mag. It's maximum "PSI" number is 36,000PSI. Does that mean that 40,000CUP = 36,000PSI? As far as the rating it does, in actuality, I don't think anyone is sure!

Gun 4 Fun · Nov 13, 2009

Tell,

It is not a hot button issue for me, and there is no need to get all worked up about this, but we do need to look at realistic numbers. I don't know anyone who uses a test barrel to shoot their loads. We all use production guns and that is what I use for determing the dimensions. The numbers you are using are from only one side of the chamber. The walls encompass the case in a complete circle. You have to consider that the steel is .009" thicker all the way around which is .018" in any two opposite directions.

As far as pressure guns being used in the manuals, re-read my post. They did not have them for all of the cartridges they provided data for. Of course they had them for some, but not all. There is no way to know for sure which loads were pressure tested and which weren't, without them actually saying so in the text.

Tell Sackett · Nov 13, 2009

Gun,
When measuring the "dangerous difference" in the cylinder, wouldn't it stand to reason that it would be the difference from the outside of the cylinder or the lug notch to the outside of the chamber since that is the thinest part of the cylinder? If a gun is going to blow because of an unsafe round, wouldn't it take the lines a least resistance? Towards the thinest area? That is what you said in your previous post. That measurement is only half the difference of the size of the chamber as the centerline of the cartridges is in the same line in both guns, right?

The difference in the two calibers of material from the chamber to the outside of the cylinders on the two firearms I have is .011". Yours maybe different, that's fine. Everything made by man has it's tolerances. Seems like .002" is well within that range.

Gun 4 Fun · Nov 13, 2009

This guy probably knows more about this than any of us. Anyone interested in trying warmer than normal loads for their 45/ 45AR should read is comments on the S&W 25/625's. The first article is on the .45 Colt, but the chamber walls are the exact same as the .45 ACP/AR guns

Gunnotes...Smith & Wesson Mod 25-5

Scroll down to the bottom of this article to find the notes on the S&W 25 platform.
Linebaugh's Custom Sixguns - Heavyweight Bullets

Gun 4 Fun · Nov 13, 2009

Tell -
re-read the post with the figures in it. You will see that their is a difference of .016" at the thinnest point, which is the bottom of the cylinder stop notch. That is where almost all guns will let loose first, and that figure is quite a difference. That was taken from measuring 5 different guns, 2 29's from different time frames, and 3 different 25's from different time frames. The factory has been pretty consistant over the years in dimensions, I'll give them that.

The difference in the two calibers of material from the chamber to the outside of the cylinders on the two firearms I have is .011". Yours maybe different, that's fine. Everything made by man has it's tolerances. Seems like .002" is well within that range.

I understand your logic, but in reality it doesn't work out that way the 5 guns checked. The stop notches are consistantly deeper on the 25's than on the 29's.

Gun 4 Fun · Nov 13, 2009

Just for the record-

I believe that the 25/625 will stand a bit more than 23,000 PSI, but that is still a very powerful load in a .45, and going beyond that just causes accelerated wear and tear. I just don't recommend it to anyone when there are more appropriate guns out there to do that. You can safely push 255 grain cast swc to 1,000 fps at 23,000 psi which is all that is needed for the lower 48. Why go further?

Tell Sackett · Nov 13, 2009

From the Smith area, and to this point I agree. The cylinders are designed to withstand about the same pressures. That is the only point I was speaking to:

In reality the Model 25-5 is about 80% as strong as the Model 29 in the cylinder area. The frames are the same and are designed for a 40,000 psi load

I like this part of the article too:

As with any gun and load data, work up carefully. I assume responsibility only for the ammo I myself assemble.

Gun 4 Fun · Nov 13, 2009

Tell-I don't think I understand your post above.

According to Linebaugh, the frames are the same strength, not the cylinders.

The 25 cylinders are about 80% as strong as the 29's, and I came out at 77% using my guns, so we are close.

I think the frames were what you were referring to and not the cylinders, no?

And yes, on working up a load, we agree wholeheartedly.

That is the sole responsibility of the person doing the loading, and shooting. It should be undertaken with a great deal of care, and a good working knowledge of proper procedures and techniques, along with using known and published data.

zeke · Nov 13, 2009

Sierra Manual # 5 has a seperate section for 45 acp revolvers, if anyone would care to check more current load information. It says the data is for the revolvers listed, but am unsure if they mean the revolvers referenced in the introduction section, or the one revolver used for the testing.

45 ACP/45AR

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