Max black powder load?

[AbitNutz]

Can you overload a 45/70 or 45/100 cartridge using black powder? If I were to just fill the cases with 2F or 3F and compress it with the bullet....could I get an over pressure situation?

[sharpsguy]

No. But if you compress a full case of powder with the bullet, chances are very good that the amount of pressure required to compress the powder will be enough to swell the nose of the bullet enough that it won't chamber. The answer is to use a separate compression die to pre-compress the powder enough to seat the bullet, thus avoiding deformation of the bullet nose. This is common and accepted loading practice in BPCR, and is done routinely.

[BRUCE MOULDS]

not only can the bullet upset and increase diameter if used for compressing, but there comes a level of compression that will bulge the case, also making chambering difficult or impossible, even when using a compression plug.
experience will teach you how much is too much.
if you are using bore diameter pp bullets you will only be seating them about 1/8" in the case.
compressing powder that much probably will not bulge a case.
keep safe,
bruce.

[rfd]

you can never overfill with black powder, but as mentioned above, you really never wanna use the bullet as a device for compressing the powder. always use a separate device, even if it's just a hand pushed dowel, to compress the powder before seating the bullet - typically with an over powder wad, and not directly on the powder.

[Ballistics in Scotland]

WW Greener illustrates one of his big game rifles, I believe on the Field action, which he claims was blown up by the use of an excessively fine-grained foreign powder. Mind you, I am very doubtful about that. It seems more likely that it was one of the semi-smokeless powders which were in use at that time. That could have contained smokeless, and yet looked and smelt like just black powder had been used.

Just the same, I would beware of using excessively fine grained black powder in a weaker action. I don't think the .45-70 can be overloaded with black powder for any sound rifle, if really coarse grains are used.

[Ballistics in Scotland]

No. But if you compress a full case of powder with the bullet, chances are very good that the amount of pressure required to compress the powder will be enough to swell the nose of the bullet enough that it won't chamber. The answer is to use a separate compression die to pre-compress the powder enough to seat the bullet, thus avoiding deformation of the bullet nose. This is common and accepted loading practice in BPCR, and is done routinely.

Not only that but black powder is irregular, gritty stuff, and the compression will tend not to be equal all the way down to the case-head. Sometimes the compressed part of the charge will go further down than others. My inclination would be to not compress. But if I did, I think high pressure, more than even the optimistic would want to give with the bullet, would produce the best consistency.

[AbitNutz]

I wasn't thinking of using the bullet as a powder ram, so I apologize if I was unclear on that. I just wanted to know if I fill the case to it's normal capacity, could I over fill it and blow up the rifle. I have a 450 Nitro Express on a Modern 1878 Sharps action with a stainless steel barrel. The case is gigantic, about the same as a 45-120 or so. I have a range of 458 bullet molds I can use, from 300 grains up to 480 grains....but I have never shot black powder in this rifle.

[montana_charlie]

For some reason, you are asking this question on a paper patching forum.
If you plan to use paper patched bullets, you probably know that it is a very common practice to set the bullet only a tenth of an inch into the case mouth.

Loaded this way, you could probably get enough compression of the charge using only finger pressure.

[kokomokid]

Agree with Charlie, I have no problem getting 81 grains of 1 1/2 swiss in a starline 45-70 with very little compression but anyone using 4f or null-b (american size) might have a pipe bomb. Dont know what the pressure spike would look like.

[AbitNutz]

Yeah, that was my mistake...I should ask the mod to move this to the correct forum.

[Oyeboten]

Agree with Charlie, I have no problem getting 81 grains of 1 1/2 swiss in a starline 45-70 with very little compression but anyone using 4f or null-b (american size) might have a pipe bomb. Dont know what the pressure spike would look like.

Post # 10 in the thread for which I have posted the link below, quotes some figures for 4F in contrast to 3 F in an 1851 Colt 'Navy' anyway.

http://castboolits.gunloads.com/showthread.php?315680-Questions-about-4-F-Powder