Black Powder Handgun PSI

Lyman’s 1st Edition handbook is the only place I know of showing pressures in revolvers. Unfortunately I only have the 2nd Edition which does not show this. However a fellow on another forum posted the Goex 4F loads showing pressures with a .451” ball:



4F was used in the Hazard’s paper cartridges, as well as in many of the BP cartridges, including larger calibers. The pressures shown in the above load is well below the threshold of what’s claimed, though I’d never recommend using it to anyone, and don’t myself as the performance I get from 3F Olde E and T7 are plenty for my needs. If these powders weren’t available I would begin testing it though.

I just searched to find a table which converts lead pressure units to PSIA or CUP, and no such thing exists. This pressure measuring system depends of the deformation of a pellet, be it copper or lead. Lead is used in very low pressure devices. A static load is applied to a pellet, the deformation measured and the reasoning was, chamber pressure that gave that much deformation was the same. Unfortunately the deformation of the pellets in real time was always slower, and thus the crusher method provides a number that is smaller than the actual pressure peak.

But, you can safely assume any black powder pistol was designed and built for loads under 10,000 psia. There is no reason to use alloy steels, or high alloy steels, or heat treat them in a black powder application. Original muskets used wrought iron barrels, I think Colt used plain carbon steels, "crucible steels" for the cylinders of his revolvers, but these period steels are weak compared to what comes out of a modern foundry.

SAAMI MAP for 45LC is 14,000 psi, and extremely conservative number based on its standardization at a time when there were lots black powder era SAA out and about. So, “less than 14,000 psi” is one data point. Italian reproductions are proofed under the CIP and should bear a proof mark. I seem to recall 1 Bar, which is about 14,500 psi.

Doc, your decimal is in the wrong zip code.

.38 Special said:

Doc, your decimal is in the wrong zip code.

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Correct. Should be "1K bar"

Slamfire said:

I think Colt used plain carbon steels, "crucible steels" for the cylinders of his revolvers, but these period steels are weak compared to what comes out of a modern foundry.

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Howdy

Colt used iron for their first frames and barrels. Iron similar to what we would call today Malleable Iron.

That includes all the old Cap & Ball revolvers. They used iron for the cylinder and frame of the Single Action Army from 1873 up until approximately serial number 96,000 in mid 1883. From that time up until about serial number 180,000, mid 1898, cylinders and frames were made of transitional low/medium carbon type steels. After mid 1898 they began using medium carbon steels for frames and cylinders. Later versions of this material were heat treated. By 1900 Colt improved the heat treatment of these steels so that in 1900 they felt confident factory guaranteeing the frames and cylinder for standard factory load Smokeless powder cartridges. 1st Gen 357 Magnum cylinders (1935) were made from fine grain, higher tensile strength ordnance quality steel.

This information is from Jerry Kuhnhausen's The Colt Single Action Revolvers, a Shop Manual, Volumes 1 & 2.

DocRock said:

Italian reproductions are proofed under the CIP and should bear a proof mark. I seem to recall 1 Bar, which is about 14,500 psi.

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BEWARE!

While there are CIP specifications for .45 Colt because it is a cartridge, Italian reproduction Cap-n-Ball revolvers, while proofed in a CIP house do not necessarily match the specifications for what we might call a similar cartridge. Each CIP house matches the next when it comes to pressures in cartridges that have transitioned into smokeless offerings, but there is NO standardization for proofing of muzzle loading barrels NOR of Cap-n-ball cylinders, It's up each proofing house to set their own standards when it comes to those type firearms. The German and English proofing houses, for example, have a much higher standard than their Italian counterpart.

FYI for folks who want to hand load for a conversion cylinder, look at your ammo recommendations. Mine when I bought it years ago said black powder/black powder substitute cartridges or ammunition loaded for CAS competition. They didn't want folks handloading if it wasn't black powder, or a black powder substitute, handloads....but it was ok to use "factory" ammo for CAS. Well I looked at the Hodgdon Manual, at the loads for pyrodex and the pressures, and the max pressure they listed. So then I looked up a smokeless recipe in the same manual that came in well under the max pressure for the pyrodex. I used that. Worked fine, except that due to the low case volume of the powder I'd get some powder particles not completely consumed, until I switched to hotter primers.

I'm not recommending this for anybody; just relating what I did.

LD

Loyalist Dave, I hear (see ?) what you're saying and I follow what my conversion (45C) instructions said which is smokless powder 1000 fps or less. That pretty much (except for the lightest weight bullets) says I'm safe with any 1st tier loads (no matter what bullet weight) but even the light weight bullets don't exceed 1st tier (14000 psi) loads.

I've got to think that unless I'm a total moron that I wouldn't offer a product that would be dangerous at 15,000 psi but fine with 14,000 psi ! I would want a MUCH bigger "cushion" than that (so Murphy could show up) !! So even those that want to say "fps" doesn't mean anything as far as pressure, I would say "they" wouldn't tell you that if it meant their demise as a company!!

Mike

Howdy Again

I too have 45 Colt conversion cylinders for a pair of 1858 Remingtons.






The instructions that came with the cylinders concerning ammunition are pretty useless. Notice what I circled in red. 750 fps to 850 fps. No mention of bullet weight, no mention of pressure. I have said this a bazillion times. it is pressure that blows up cylinders, not velocity. Even if the bullet weight were defined, that would still not define a safe cartridge for these cylinders adequately. Any one who has perused reloading manuals knows that widely different pressures can be achieved for the same bullet weight and velocity by varying the type of powder used. Without a specific reference to pressure, this information is useless. Luckily I don't care, I only shoot my Remmies with cartridges loaded with Black Powder. By the way, the other side of the instructions states these cylinders are made with 4150 arsenal grade steel, and the caps are made with 4140 steel, which is pretty good stuff.

Which is, again, apples and oranges! The instructions for my "Kirst gated" conversions says plainly 1,000 fps or less! If you look at reloading tables, you can see clearly that none of the 250 -255 gr bullets exceed 1000 fps (which is less than 14,000 psi)! And only a few " light weight " bullets do exceed 1,000 fps but are still under 14,000 psi. I'm not even sure that you can get the really "light weight" bullets from "commercial" offerings . . . !

Besides that, each manufacturer of conversion cyls has their own "warnings" and should be followed.
The "end cap" conversion cyls (such as the cyls for Remingtons such as DJ has (non gated!) are less "robust" than those with a full conversion ring. The "cap" version has maybe a 1/3 of the support that a full " conversion ring" has (like a Kirst has). So, LOOK at the instructions for your cyl. and keep everybody happy!! I know I do!!

I am close to offering the first "gated conversion" for the ROA (hopefully this summer) which will allow "Ruger only" loads as well!! If I weren't EXTREMELY sure of this, I would just say "anything off the shelf" but that's not me!!

Mike

Velocity and pressure do not have a linear relationship. A cartridge overfull and compressed of Trail Boss will deliver sub 1000 fps velocity with virtually any bullet weight. It will also deliver violent pressure spikes. As DJ notes above, a velocity maximum is largely useless. Happily, we have reloading manuals that give us approximate pressures for various loads and, if one insists on loading smokeless cartridges in black powder revolvers, it would behoove one to stay below 14,000 psi or the maximum proofed by the frame manufacturer, given that the conversion cylinder manufacturers do not give useful guidance.

Oh, I thought I pointed out that none of the loads given in a loading manual show a velocity over 1,000 fps (except for some of the lighter bullets which I don't think are offered by most manufacturers) which means all the loads that one would make under 1,000 fps would automatically be under 14,000 psi. Therefore, the cylinder company makes it fairly simple to cover itself by simply stating no loads over 1,000 fps.! That automatically means a load won't be over max pressure.

It's a simple way for the "non-loader" to understand not to get any "hotrod loads" that would be of higher pressure (such as the Buffalo Bore brand or any other "boutique" hotter than tier 1 loads).

This keeps the cylinder manufacturer from having to get into a lecture about reloading and pressures not being linear with velocities . . . something the average Joe (or Jane) doesn't necessarily know or care about. But an easy way to keep the customer safe is easily done by letting them know not to shoot any ammo over 1,000 fps.
(As an aside, I've never seen a 45C load listed in a loading manual that suggests a compressed, over full case of Trail Boss for a tier 1 load . . . maybe I need to update my manuals . . . )

For those of us that "insist" on shooting smokless ammo in "black powder" guns, I'm pretty sure the frames don't care! I know I didn't tell mine! After years of the same diet in all my 45s (Dragoons, '60 Army, El Patron, Remington conversions ), not one problem has come from it.
I'm quite sure the conversion manufacturers know "what we're up to".

Mike

45 Dragoon said:

Oh, I thought I pointed out that none of the loads given in a loading manual show a velocity over 1,000 fps (except for some of the lighter bullets which I don't think are offered by most manufacturers) which means all the loads that one would make under 1,000 fps would automatically be under 14,000 psi. Therefore, the cylinder company makes it fairly simple to cover itself by simply stating no loads over 1,000 fps.! That automatically means a load won't be over max pressure.

It's a simple way for the "non-loader" to understand not to get any "hotrod loads" that would be of higher pressure (such as the Buffalo Bore brand or any other "boutique" hotter than tier 1 loads).

This keeps the cylinder manufacturer from having to get into a lecture about reloading and pressures not being linear with velocities . . . something the average Joe (or Jane) doesn't necessarily know or care about. But an easy way to keep the customer safe is easily done by letting them know not to shoot any ammo over 1,000 fps.
(As an aside, I've never seen a 45C load listed in a loading manual that suggests a compressed, over full case of Trail Boss for a tier 1 load . . . maybe I need to update my manuals . . . )

For those of us that "insist" on shooting smokless ammo in "black powder" guns, I'm pretty sure the frames don't care! I know I didn't tell mine! After years of the same diet in all my 45s (Dragoons, '60 Army, El Patron, Remington conversions ), not one problem has come from it.
I'm quite sure the conversion manufacturers know "what we're up to".

Mike

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It's remarkable that people allow you to work on their firearms. Really.

DocRock said:

It's remarkable that people allow you to work on their firearms. Really.

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Ok, I'll play.

I just checked my manual and found 1 max load for a 230gr. cast L RNFP (out of 8 powders) that listed a max vel. of 1003 fps. with a 13,200 psi .
As for 250gr. cast LRNFP there was 1 max load listed at 1014 fps at 13000 psi. This was from a list of 12 powders. All the other loads for 230grs and up were less than 1000 fps (43 listed loads)

So, since this is from a reloading manual, it is up to the individual to be responsible for the ammo they build. Even though 2 examples were found right at the 1000 fps threshold, guess what?? All 43 maximum loads listed were "safe" . So, using the 1000 fps max warning from the conversion cyl company, the shooter would be safe with even the max loads listed in the manual. I don't really see what makes this so difficult for some people.

As far as off the shelf ammo, I'm pretty sure 230gr. 250gr. and 255gr 45Colt standard ammo is all less than 1000 fps . . . I could be wrong but last time I checked what was available there were none. I've been loading since about 1985. The only loads I buy are SD loads.

And as for the snide remark, my guns are winning state championships and don't break. That's why they let me tune their revolvers, Really!!

Mike

45 Dragoon said:

I've got to think that unless I'm a total moron that I wouldn't offer a product that would be dangerous at 15,000 psi but fine with 14,000 psi ! I would want a MUCH bigger "cushion" than that (so Murphy could show up) !! So even those that want to say "fps" doesn't mean anything as far as pressure, I would say "they" wouldn't tell you that if it meant their demise as a company!!

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No doubts about folks who go in for such revolvers and their conversion, would likely be diligent. My comment was merely pointing out that when one mentions CIP and Proofing, and then starts talking about black powder revolvers, folks should know that the CIP and BP Proofing are not required to be compatible.

Obviously, in a manufactured product, there will be a safety limit set, which will be below the actual known failure level. They are trying to mitigate their liability from the not quite so diligent fellow who screws up his handloads, and drops a double charge, or simply uses the wrong powder. The fact that even with cap-n-ball revolvers you can find folks who will use smokeless powder and blow up the piece, is enough evidence that they need to warn the operator about using smokeless powder, because they know they cannot control what happens when you get "User Error".





LD

Thanks LD! I definitely agree!!

The "cya" part is what i was trying to point out. If a manufacturer gives a "fps" limit, there must be some bearing they base that on. They also don't want to have to give an "education " to the public (which may in fact make them even more culpable). With a little investigation, one can see that according to reloading manuals, you could understand why the company would draw a line at 1000 fps. Going over that would almost surly get you into trouble and it makes that clear without having to give an education to the public at large.
Thanks for the video!! Hope that's the only way any of us ever see something like that!!
(Wow! That Remington broke all the way in two!!!)

Mike

In C.I.P. countries there are different proof marks for proofing with nitro and for proofing with blackpowder. If it is proofed for nitro then it wont get proofed for blackpowder for obvious reasons.

The new proofmarks look like

CIP
N .... nitro


CIP
PN .... blackpowder

walterelm said:

In C.I.P. countries there are different proof marks for proofing with nitro and for proofing with blackpowder. If it is proofed for nitro then it wont get proofed for blackpowder for obvious reasons.

The new proofmarks look like

CIP
N .... nitro


CIP
PN .... blackpowder

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Yes but the actual pressure level where the CIP house deems it satisfactory to place that Black Powder proof mark upon the barrel or the cylinder differs from nation to nation. Not so with the smokeless cartridges OR with black powder cartridges that are now loaded with smokeless powder, such as the .45 Colt.

LD

@Loyalist Dave
We agree on prooving for smokeless

I just looked up the data on proofing blackpowder barrels in germany: if proofed, a rifled barrel may be loaded with up to 6 grams (92 grains). If you need loads beyond that, it can be proof tested, the max load will be stamped on the barrel.

There is no mentioning of pressure, speed .... the ball weight is mentioned.

A slightly compressed load of BP with a ball seated such that it is almost slush with the front of the cylinder is usually viewed as a maximum working load in a cap and ball revolver.
OK, now how are you going to proof it? Since a working load has filled the chamber? I researched CIP and the British proof systems and found specifications for rifle proof loads, but never for a cap an ball revolver. I've always wondered how they did it.

I dunno, but everything I have ever read is the Italians proof everything, including Cap & Ball revolvers.

The thing I have always wondered about is who cleans them after they have been proofed?

DJ, I have wondered the same thing, but now I wonder if I've actually loaded a "slush" ball and didn't know it!!!! (Just teasing unsellable!)
Hmmmmmm . . .

Mike

Proofing c&b revolver. ..

I have seen an info regarding bp proofing in ulm but cant find it anymore ... therefor ...

They put as much swiss powder no1 as possible in each chamber of the cylinder, seat the bullet, fire it ... thats it

Oh ... this is the proofmark from ulm .... just in case you have a walther ppk and wonder

Every Italian made cap and ball revolver I've handled has had proof marks.