Nitro in a BP revolver.

[Turnup]

A friend of mine has obtained some nipple replacements which with small modification to the hammer allow the use of shotgun primers in his .45 Cattleman repro . He has been told that he can put up to 3 grains of nitro in it, which he has been using with no ill effects (so far). The gun is clearly marked "BP only". It has not been re-proofed for nitro.

Unfortunately he has now obtained a Chrono and is finding MV to be far too low with ball and (naturally) even lower with the much heavier bullets he has started casting. He wants to up the load. I have expressed some concerns at this (both the starting point and his ambitions to up the load) since I believe that the pressure curve with nitro is much shorter and steeper than with BP.


Anyone admit to doing this?

Anyone know what BP vs nitro proof load pressures are?

Short of re-proofing it is there any way to safely explore this whole idea?

How can you determine if safe limits are being reached?

Would it be feasible to assume that if MVs are kept within reason (he wants to get to 750fps) then peak pressures are not excessive?

He is shooting on land he owns and AFAIK there is no legality problem with this.

[tacfoley]

A friend of mine has obtained some nipple replacements which with small modification to the hammer allow the use of shotgun primers in his .45 Cattleman repro . He has been told that he can put up to 3 grains of nitro in it, which he has been using with no ill effects (so far). The gun is clearly marked "BP only". It has not been re-proofed for nitro.

Unfortunately he has now obtained a Chrono and is finding MV to be far too low with ball and (naturally) even lower with the much heavier bullets he has started casting. He wants to up the load. I have expressed some concerns at this (both the starting point and his ambitions to up the load) since I believe that the pressure curve with nitro is much shorter and steeper than with BP.


Anyone admit to doing this?

Anyone know what BP vs nitro proof load pressures are?

Short of re-proofing it is there any way to safely explore this whole idea?

How can you determine if safe limits are being reached?

Would it be feasible to assume that if MVs are kept within reason (he wants to get to 750fps) then peak pressures are not excessive?

He is shooting on land he owns and AFAIK there is no legality problem with this.

There is one VERY good reason why BP loads and nitro loads are not usually interchangeable. The material from which BP handguns are made is NOT of the same grade as that used to make nitro-firing guns. The elastic limits of a cylinder designed for 18-20 kpsi maximum are reached much quicker when you are shooting loads with pressures double that.

Your friend might find that out the hard way.

He can do what he likes on his own land. So long as he has someone who'll know where he is to go look for him.

[loiner1965]

as tac says bp only.
i would like to know how strong the pietta bp pistols are though as they supposed to be made of modern steel etc.
just to make sure.......i am only curious and would never use smokeless in any bp pistol.
on a side note......uberti make nice .44 russian revolvers that use smokeless loads....are these made of different steel ?

[tacfoley]

as tac says bp only.
i would like to know how strong the pietta bp pistols are though as they supposed to be made of modern steel etc.
just to make sure.......i am only curious and would never use smokeless in any bp pistol.
on a side note......uberti make nice .44 russian revolvers that use smokeless loads....are these made of different steel ?

Must be so. Although the original was a BP load. Remember that over in the US the Ruger Old Army has a following of people who regularly swap out the BP cylinder for a .45 lead bullet only Long Colt cartridge-firing version. You'll recall that ALL ROAs are made of high-grade stainless steel in any case. But even so, the Nitro cylinder is entirely a new one and must have different heat treatment to increase its mechanical performance.

[enfield2band]

I would not use nitro in a BP revolver, or any BP gun.
I don't think the steel is good enough to stand the higher pressures. I suspect that many reproductions use the minimum grade steel and are case hardened to reduce wear.
The quality of the steel on originals, locks, triggers etc. is harder than modern reproductions. And the steel on some original barrels seems better too.

I have not tested the hardness of the metal but how a file or oil stone cuts the surface is a fairly good guide.

The priming compound in a shotgun primer is probably 2-3 times more than an ordinary N0.11 cap. That extra brissance from the shotgun primer will help to increase the pressures with the nitro. It is like using a magnum primer!

He should try the shotgun primers with BP and work a load up.

[sclg]

Short of re-proofing it is there any way to safely explore this whole idea?
Not unless you are attracted to the idea of possible maiming.

How can you determine if safe limits are being reached?
It's safe until it isn't.

Would it be feasible to assume that if MVs are kept within reason (he wants to get to 750fps) then peak pressures are not excessive?
No!
Standard ballistics curves show you the chamber pressure against distance travelled down the barrel. The area under that curve is the bullet velocity. Hence if you want more velocity you need a longer barrel or a higher chamber pressure. The problem is that a) he has no idea what peak pressure he's generating and b) he has no idea what peak pressure is excessive.

There are far too many unknowns.
S

[tacfoley]

He should try the shotgun primers with BP and work a load up.

Quite. The rest of your post is therefore unnecessary - you've said ALL that is needed.