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Large case reloading, Pack or not
I have 2 large case rifles, a 1876 Martini and 1873 Beaumont. I have been shooting the MH with a 485 Gn cast, with 47 gns of 3031, packing the case with kapock, and a disc to keep all the powder down by the primer pocket. So far so good. When I purchased the Beaumont a couple of weeks ago the shop owner/gun smith advised me against using the packing as he said it would create a shock wave of some type that had the potential to bulge the barrel. He further advised that he had run across a number of rifles where this happened. He recomended that I switch to 5744 as a slow burning alternative and forget the stuffing. How is this problem approached by others on this forum. I am hesitant on filling such a large case with so little powder and sort of having it lay about all over the case, not necessarily by the primer.
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06-01-2010 08:52 AM
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Garra, I have no experince with large volumes cases, although I know some lads who have used trailboss to great success in a variety of applications.
IMR Powder Profiles: Trail Boss is the link
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Advisory Panel
Feed your BPCR rifles with BP, and life is a little less hazardous! The Martini-Henry case is awkward enough with a black powder load. Putting nitro into that huge case is adding an extra challenge.
There are two major worries: 1) Ignition, when the charge is (volumetrically) so small, compared with the case volume, that the powder is lying on the bottom (which is why a filler is almost unavoidable). The general opinion seems to be that it is a good idea to use magnum primers to make sure of powder ignition. As I once had a bad experience with a commercial nitro load for a 45-70, where the primer simply pushed the bullet into the throat without igniting the powder, I go along with that principle.
2) The second worry is the theory of a shock wave caused by igniting a very low charge that fails to drive the bullet out of the case. I confess that in this case, I am only repeating hearsay, according to which in most cases where something went catastrophically bang, the cause was probably a double load (but who likes to admit mistakes?).
The best answer is: load your black powder cases with black powder. That way, you will always have a better than 50% filling (no possibility of double-charging) and will not be worried about overloading a system that is at least 120 years old. Most people use a bit of filler with the M-H case, in the interest of saving their shoulders ( a full case would require about 85 grains of powder, but more than 70 is just painful, without improving accuracy) but the best M-H shooter I know doesn't even bother with that, following the principle of "the fewer variables the better". And cleaning a BPCR rifle is a lot simpler than cleaning a muzzle-loader.
Just to provoke a bit of comment: would you put dragster fuel into a vintage car? No? Then why try the equivalent with a rifle that is much older than any automobile?
Patrick
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Use Dacron fiber and don't worry. Kapok doesn't get consumed by the flash the same way Dacron fiber does.
When they tell you to behave, they always forget to specify whether to behave well or badly!

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The cover of the Cast bullet book looks real familiar, hate to think I may already have it. I have never done BP loading before, so I am kind of hesitant. Isn't there a powder that is a replacement that fills the case, but is low pressure. Of course that would be too easy. May have to bite the bullet and get started, it sure would make firing these old beauties a bit easier. I am going to look at an old Italian
rifle tomorrow, another possible BP user.
thanks all,
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There's several black powder substitutes, but the original propellant works VERY well. Run hotter primers, use a home made copper drop tube, SPG lube, and a cardboard wad (waxed is best).
MV variations are less (sometimes in the single digits over a ten shot string!) when BP is used and your loading technique is uniform. Ask what the long range BPCR shooters have done as regards accuracy- it's pretty amazing!
Clean up is really easy, except for the added chore of washing the cases, less likelihood of leading, and it's what the firearm was designed around.
You are going to have to cast your own bullets for these rifles for best results regardless of powder used, so why not not go all the way, it's very little extra trouble once you've sorted out the few extra steps.
Don't worry about ruining your barrel by using BP, after all, the VAST majority of rounds that have been through it were just that, and it survived until now...
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Well I checked and I did have the book. Something on Ed's comments with the reloading chart is interesting. The amount of gns of powder using Unique vs 3031 or others. Almost as high as a pressure is attained with a lot less powder percentage wise. They share the Dacron pad, so is the higher pressure just attained because that burns so much faster?
Didn't get the Italian
one, but got a Swiss
M81 Vetterli instead, another BP rifle.....
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Advisory Panel
Dear Edward,
as interesting and amusing as your contribution is, it seems to be slightly missing the point and may be confusing to the original contributor.
1) The 303 cartridge was one of the many responses to the shock effect of the introduction of the Lebel cartridge with smokeless powder in 1886. As the British
had not yet got an acceptable smokeless powder, the loading of the 303 case with black powder was a stopgap measure, and they had to use some tricks to force enough powder in to the case! In other words, the 303 was not designed as a BP cartridge, and your comment "If the .303 British can make the change over from black powder to smokeless powder other cartridges can also take advantage of “smokeless powder” " - is therefore an incorrect interpretation of the historical development.
In the "Handloaders Manual of Cartridge Conversions" it says:
303 case capacity = 55.65 gns of water
577-450 case capacity = 123.20 gns of water
Which means that the 20 gns of powder in the 303 case in your picture would look very meagre in the 577-450 case, which is 2.2 times larger.
Furthermore, the loading on P.234 of the "Cast Bullet Handbook" which you present shows pressures that are specified for the Ruger #1 and #3, but are NOT acceptable for original BP rifles. Loads for original rifles are shown on P.232-234, and have considerably lower pressures.
As to the relative burn rates of BP and nitro powder - it surely depends a lot on the packing density. The 16" sharges for the Iowa class battleships use (used?) a black powder starter charge, as it appears that BP does indeed ignite faster than smokeless under pressure.
Which leads me to the final point, on which I hope you have some info in your capacious store of information. And that is, the mysterious "shock wave" supposedly caused by minimum loads of smokeless powder. Often heard of, but I have never seen any proper documentation, rather some comments to the effect that in most (all?) properly analyzed cases, the cause was erroneous double charging. I suspect there may be a certain mythological content in the shock wave story, and would be grateful if you could dig up any properly researched reports.
Whether or not the cheap gentlemen of doubtful parentage have more fun I cannot say - I leave that to your personal expertise - but it is the stupid ones who worry me!
Patrick
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