Loading 25 ACP

BC38 · Dec 16, 2020

I'm contemplating getting a set of dies and starting reloading for a couple of mouse guns. I have a question for those who have some experience reloading 25acp.

First, when I look at BBI it shows data for some standard 50gr RN ammo in the range of 15,000 - 16,000 PSI and 700-800 FPS.
Looking at my reloading data books and online sources the data for the 50gr RN bullets is all pretty much in those same ranges.

BUT, when I look on the SAAMI site it says that the max pressure for this round is 25,000 PSI. Seems to me that there ought to be some handloading recipes to could create some rounds with significantly more "zip" that would still be within the SAAMI pressure specs.

So just out of curiosity, why are all the published loads so anemic? What am I missing here?

nbedford · Dec 16, 2020

Most manuals indicate what they used as a platform to test the loads. Maybe most were using something like a Raven 25 auto. Blowback operated; so I expect the loads would be moderate.

BC38 · Dec 16, 2020

nbedford said:
Most manuals indicate what they used as a platform to test the loads. Maybe most were using something like a Raven 25 auto. Blowback operated; so I expect the loads would be moderate.

Yeah, that would make sense for some of them, maybe. But for ALL of them? I suppose they could all be developing and testing loads based on the lowest common denominator like that, but it would seem really odd - because there were a LOT of quality 25ACP guns around long before the Ravens and Lorcins were ever even thought of. Beretta Jet Fires, Colt Vest Pockets, Browning FNs, these are all quality firearms, not pot metal junk. I've been looking at load data from 25 and 30 years ago and am still only finding the whimpy 15k pressure loads. Its really weird.

crstrode · Dec 16, 2020

Lyman #49 says 1.4 grains of 231 yields 752 FPS at 17800 CUP from a 2-inch bbl.

The Hornady 3rd lists 1.6 of 231 as a maximum with no specific pressure listed. They show 850 FPS from a 2-inch bbl for that load.

I reload the 25ACP using 1.4 of 231. It has been years since I reloaded that one, and didn't have a chrono in those days.

It functions well, and is VERY loud out of a Baby Browning. Of course, even weenie loads are ear-splitting from those little pieces.

I should note, that reloading the 25ACP is a bit of a challenge, even with my smallish fingers. Finding components is harder - even in good times . . .

crstrode · Dec 16, 2020

By the way - I really like the 25 ACP. Pay no attention to those that blather it is weaker than a 22LR. Most ballistics data for the 22LR is from rifle barrels and not sub-2"-inch vest guns.

Most 25 ACP nay-sayers also fail to consider the 25 ACP sizzles along at about the same speed, but with a fatter and much heavier bullet.

The BBI data show that position as a valid one.

Qc Pistolero · Dec 16, 2020

I'd be glad to help with some info but I stopped at the .32acp;I could barely handle those tiny things.The .25 is a desperatly too small component item for my patience to handle!
But fun to shoot it is;kinda different of the .22.I just lowered my standards as a caster/reloader to buying factory ammo for that one.

BC38 · Dec 16, 2020

crstrode said:
Lyman #49 says 1.4 grains of 231 yields 752 FPS at 17800 CUP from a 2-inch bbl.

The Hornady 3rd lists 1.6 of 231 as a maximum with no specific pressure listed. They show 850 FPS from a 2-inch bbl for that load.

I reload the 25ACP using 1.4 of 231. It has been years since I reloaded that one, and didn't have a chrono in those days.

It functions well, and is VERY loud out of a Baby Browning. Of course, even weenie loads are ear-splitting from those little pieces.

I should note, that reloading the 25ACP is a bit of a challenge, even with my smallish fingers. Finding components is harder - even in good times . . .

Yeah, the only readily available source of 25 ACP bullets I have found so far is RimRock, and they ain't cheap either.

I found the same kind of numbers you did. Note that the Lyman W231 load was measured in CUP, not PSI. All of the CUP data I have found for the 25ACP round show higher CUP pressure numbers (17,000-18,000 CUP, vs 15,000-16,000 PSI) for approximately the same velocities.

From that it would seem to be a relatively safe assumption to extrapolate that the 17,800 CUP numbers for rounds that do 750-ish FPS are roughly equivalent to the 15,500-ish PSI numbers for rounds that also do 750-ish FPS.

So even though the numbers are higher when measured in CUP they should still be in the 15,000-16,000 PSI range which means they are still WAY below the SAAMI published max of 25,000 PSI.

If CUP and PSI scaled linearly (they don't), given that loads producing 15,500 or so PSI are roughly equal to loads producing 17,800 CUP or so (based on them having equivalent velocities), then the SAMMI spec of 25,000 would translate to around 28,800 CUP. Again, WAY higher than the published 17,800 CUP of that W231 load from your Lyman book.

BC38 · Dec 16, 2020

Qc Pistolero said:
I'd be glad to help with some info but I stopped at the .32acp;I could barely handle those tiny things.The .25 is a desperatly too small component item for my patience to handle!
But fun to shoot it is;kinda different of the .22.I just lowered my standards as a caster/reloader to buying factory ammo for that one.

I kinda wonder about that too, but then I realized I have no problem with handling the 55gr .224 bullets to load my 223/556 rounds, so why not 50gr .25s? How much harder can it be?

BC38 · Dec 16, 2020

crstrode said:
By the way - I really like the 25 ACP. Pay no attention to those that blather it is weaker than a 22LR. Most ballistics data for the 22LR is from rifle barrels and not sub-2"-inch vest guns.

Most 25 ACP nay-sayers also fail to consider the 25 ACP sizzles along at about the same speed, but with a fatter and much heavier bullet.

The BBI data show that position as a valid one.

Yeah, the BBI velocity data for the two rounds are very comparable, though they sure did test a lot more .22 loads than .25 loads. I like the reliability and reloadability of the .25, and with a quality gun by Beretta, Colt, FN, etc, I see no reason why loads in the 22,500 PSI range couldn't be developed. THEN the little .25 mouse gun might be quite a bit more viable in a last ditch SD scenario.

Using a ME calculator bumping the 50gr .25 cal pill from 750fps to 1250fps takes it from just under 70 ft-lbs ME up to just over 190 ft-lbs ME - almost triple the ME. Even taking it up to just 1,070fps raises the ME to just under 140 ft-lbs - effectively doubling the ME. You're not going to do that with a .22

The hard part is going to be getting there safely. Though with nearly 10,000 PSI difference between published loads and the max SAAMI spec, seems like working up to something in the 1,100 FPS range in a quality mouse gun should do-able.

noylj · Dec 16, 2020

25000 psi is the maximum AVERAGE pressure. SAAMI specifies three different pressure functions (maximum average pressure, maximum probable Lot Mean Pressure, and maximum probable sample mean pressure, along with maximum extreme variation) and the load has to be below all three.
So, for a 50gn .25 Auto load, max avg. pressure is 25000, maximum probable lot mean pressure is 25800, and maximum probable sample mean pressure is 27000. If the test load doesn't meet all three, it is rejected.
I could well see pressure spikes being something real common in that little case, where the average pressure is limited because going over just gives unsafe pressure spikes or other failures.

BC38 · Dec 16, 2020

noylj said:
25000 psi is the maximum AVERAGE pressure. SAAMI specifies three different pressure functions (maximum average pressure, maximum probable Lot Mean Pressure, and maximum probable sample mean pressure, along with maximum extreme variation) and the load has to be below all three.
So, for a 50gn .25 Auto load, max avg. pressure is 25000, maximum probable lot mean pressure is 25800, and maximum probable sample mean pressure is 27000. If the test load doesn't meet all three, it is rejected.
I could well see pressure spikes being something real common in that little case, where the average pressure is limited because going over just gives unsafe pressure spikes or other failures.

The max average pressure measure seems pretty self-explanatory.
The other "probable" "lot" and "sample" pressure measures, maybe not so much.
You seem well versed in this, care to explain those other two, and how even though they have higher max numbers how they could be exceeded without also exceeding the max average pressure?
And maybe how any of these three limits could be exceeded with loads listed at or around 15k-20k PSI - if that is even possible.

noylj · Dec 16, 2020

Go to SAAMI and learn.
You can have a load that produces just under 25000 average pressure, but that means that there were loads both higher and lower. Thus, a small standard deviation is needed to pass the two probable mean measures.
Then, you take the standard deviation and determine the probable lot and sample means and compare to what you got. Note that any load that has a pressure spike will almost certainly fail one, if not all three measures, and the load is rejected.
What this means for reloaders is that, ever since real time/pressure traces have existed, lots of old loads have been rejected and folks complain about data being lawyered down, when lawyers have nothing to do with, just statistics and finally actually getting some insight into what is happening in the chamber.

Krogen · Dec 16, 2020

One thing to consider is powder charging. I know it wasn't your question, however . . . With those tiny charges, the span between max and min may be 0.2 gr - 0.3 gr. Charging is going to be tricky. You may want to weigh each charge. Even then most scales only resolve 0.1 gr.

I load the 32 Long and face the same issue. I've wrestled with setting up my powder measure to throw charges. With fine grained power, it's pretty consistent. By weighing each charge, I can spot the outliers. To set up the measure I've taken to throwing 5 or 10 charges into the pan and figuring the average. Then when I go back to individual throws I have a better shot at hitting closer to the center of the error band - as best as I can measure.

Ivan the Butcher · Dec 16, 2020

BC38 said:
I kinda wonder about that too, but then I realized I have no problem with handling the 55gr .224 bullets to load my 223/556 rounds, so why not 50gr .25s? How much harder can it be?

The area to place you fist and fingers is so much smaller on a 25 ACP. You may want to consider using padded tweezers to place your bullets in the case mouth. I had plenty of problems with 32 Short and 32 ACP! I have about 75 cases, they are in boxes of range brass people give me and only keep them for fuse igniters for simulators/training munitions.

Last 25 I owned was a Raven in the Mid 90's. After replacing the firing pin, I sold it with 20 rounds of Hornady for $25.

Ivan

505Gibbs · Dec 17, 2020

Krogen said:
One thing to consider is powder charging. I know it wasn't your question, however . . . With those tiny charges, the span between max and min may be 0.2 gr - 0.3 gr. Charging is going to be tricky. You may want to weigh each charge. Even then most scales only resolve 0.1 gr.

I load the 32 Long and face the same issue. I've wrestled with setting up my powder measure to throw charges. With fine grained power, it's pretty consistent. By weighing each charge, I can spot the outliers. To set up the measure I've taken to throwing 5 or 10 charges into the pan and figuring the average. Then when I go back to individual throws I have a better shot at hitting closer to the center of the error band - as best as I can measure.

I agree with this comment. When you get this small the consistency can be an issue & you don't have a lot of wiggle room because of the small case capacity.
Loading 1.9g in a 32 long with HBWC wasn't enjoyable for consistency in my experience.

BC38 · Dec 17, 2020

noylj said:
Go to SAAMI and learn.
You can have a load that produces just under 25000 average pressure, but that means that there were loads both higher and lower. Thus, a small standard deviation is needed to pass the two probable mean measures.
Then, you take the standard deviation and determine the probable lot and sample means and compare to what you got. Note that any load that has a pressure spike will almost certainly fail one, if not all three measures, and the load is rejected.
What this means for reloaders is that, ever since real time/pressure traces have existed, lots of old loads have been rejected and folks complain about data being lawyered down, when lawyers have nothing to do with, just statistics and finally actually getting some insight into what is happening in the chamber.

Thank you for the explanation of the terms. They make much more sense with your clarification.

So basically you're saying that the deviation from load to load is the reason for "downloading" the pressures of this particular cartridge by 60% of the established standard? I'm not saying you're wrong, but if that it the reason, doesn't that seem like it would have to be due to some pretty drastic amounts of variation? Certainly far more than I've seen in the data for any other cartridge. I know the case and the charges are really small, and that has an effect. But 9mm cases are small relative to the powder charge too, and they don't get downloaded anywhere near that far.

I'm thinking that the idea of weighing each charge is probably a good plan, especially if I'm going to try to push the envelope a bit.

nbedford · Dec 17, 2020

crstrode said:
By the way - I really like the 25 ACP. Pay no attention to those that blather it is weaker than a 22LR. Most ballistics data for the 22LR is from rifle barrels and not sub-2"-inch vest guns.

Most 25 ACP nay-sayers also fail to consider the 25 ACP sizzles along at about the same speed, but with a fatter and much heavier bullet.

The BBI data show that position as a valid one.

Probably stating the obvious, but all 25 acp factory ammo I've seen is full patch, and I really don't ever recall seeing full patch 22 LR.

BC38 · Dec 17, 2020

nbedford said:
Probably stating the obvious, but all 25 acp factory ammo I've seen is full patch, and I really don't ever recall seeing full patch 22 LR.

"Full patch" is a term I'm unfamiliar with. Am I correct in thinking that is just a different way of saying FMJ?

bmcgilvray · Dec 17, 2020

1.6 grains of Unique behind a 51 grain FMJ .25 bullet gives more velocity by quite a bit than the maximum charge weight of Bulls Eye. I can and have loaded for the .25 ACP and have components laid in.

nbedford · Dec 17, 2020

BC38 said:
"Full patch" is a term I'm unfamiliar with. Am I correct in thinking that is just a different way of saying FMJ?

Yes. Older way of describing it, I reckon.
BTW, out of curiosity I looked up the factory load for it in Hatcher's Textbook of Pistols and Revolvers, pub. 1935. He called it "Metal Jacketed" and indicated the factory load with a 50 grain bullet was 1.4 grains of Bullseye = 751 fps, and the pressure was 15,000 lbs.

Loading 25 ACP

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