black powder nitro mix

[hilliard]

Hi Folks,

I shoot mainly antique black powder rifles. 45-70, 44-40, .41 swiss, .303 british (yes that originated as BP). The problem is it gives an awfull mess. I have reloaded reduced loads nitro VV110 and xmp 5477. But is not the real thing.
It must be possible to mix BP and nitro and still have no safety issues. But where to start?
BP substitutes are not available where I live in Europe.
Any ideas (other than warnings not to try)?

[Unclenick]

Other than duplex loads where a small amount of black powder is placed over the flashhole to increase the priming flame for slow smokeless powders, I don't know of any mixing currently being done? Even duplex loads are considered potentially hazardous to experiment with. I seem to recall reading some old data for pistol cartridges that mixes of up to around 50% BP don't leave the corrosive reside that pure BP does, but I'm not sure what the advantage over pure smokeless is? The hotter smokeless powder will tend to burn off a lot of the BP smoke and residue, so the result would be closer to that of smokeless powder than to that of BP, though you would still get more smoke than pure smokeless makes.

Frankly, I personally would not mess with mixing for a couple of reasons. One is that the grains of the BP and smokeless have different shapes and densities. So, even if you make the mixture perfectly homogeneous when you charge the cases, you may well find there is a tendency for one powder to migrate toward the top of the mix during transport, changing the burning characteristics. You would likely have the same problem using a powder measure; stratification in the hopper during metering. So, even if the loads are at safe pressures, they may not be very good on accuracy if some have more of the BP toward one end than the other.

The other is finding out the safe pressures? If you don't have pressure test equipment that lets you test your mix (homogenous) and test your powder combination stratified (all BP at the top of the charge and all BP at the bottom of the charge and all BP laying along one side), I'm not sure how a really safe load could be developed? Very gradually, I suppose.

[Luciano]

Find a suitable smokeless powder, Trail Boss maybe(?) or improve your cleaning method.

[Hawg]

BP and smokeless powders have drastically different burn rates. You're not going to be satisfied with the results and bp residue is not the same as smokeless residue. The smokeless is not going to burn out the bp and make cleaning any easier. To me bp cleans easier than smokeless but some people use smokeless bullet lubes and petroleum based oils or they try to clean bp with smokeless cleaners and all any of that does is make an easy job tough.

[Dingoboyx]

The smallish flash from the cap failed to light the TB enough on some shots, resulting in actually being able to see the ball go and only a dull pop, not a bang there was several FTF's and some shots sounded nearly ok, but too lite. I had thought of putting a little black on top of the cap (cap, then a little black in the cylinder, top up with TB) but wasn't sure if it was safe to mix? This way the black would see to it the TB gets lit

I will be interested in the outcome of this thread, well thunk up, OP

[darkgael]

There is info on duplex loads in Paul Matthews' "Forty Years with the .45-70". With care, duplex loads are safe. The choice of smokeless "kicker" is important. Matthews was fond of SR 4759 as a priming charge. He used a ratio of 10-15% of the BP charge - about eight grains in his 45/70 loads. He also used 2400 and H4227.
Lyman's Cast Bullet Handbook listed SR4759 as the primer in BP duplex loads. They were at about 10-11% (6.5 grains 4759 and 63 grains FFg).
Using BP in a bottlenecked case like the .303 presents you with the issue of compression. The old military loads had a factory to handle the assembly (and for the old 577-450). You and I don't have that luxury. If you can get a look at a cartridge drawing from the LOC, you can get a sense of how it was done. The original .303 BP load was a compressed pellet of 71.5 grains weight.
Pete

[Dingoboyx]

And thanks OP for bringing it up I might have to give it a go, I was thinking along the lines of just covering the cap end of the cylinder (less than a grain) the rest TB, just enough black to ensure the TB gets lit

[B.L.E.]

I have tried Trail Boss in my ROA

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The smallish flash from the cap failed to light the TB enough on some shots, resulting in actually being able to see the ball go and only a dull pop, not a bang there was several FTF's and some shots sounded nearly ok, but too lite. I had thought of putting a little black on top of the cap (cap, then a little black in the cylinder, top up with TB) but wasn't sure if it was safe to mix? This way the black would see to it the TB gets lit

I tried a similar experiment in my ROA figuring that that gun is just as strong as Ruger's cartriage revolvers. A round ball smokeless load known to be safe in a .45 cartriage revolver loaded in the ROA either failed to fire or would just be a blooper. I did try a very small amount, .22 short case of FFFg as a kicker for the smokeless powder and sucess, it went bang every time and the power was normal.
Black powder only needs to be set on fire to go off, a spark from a flint on steel is as good as a magnum primer.
I feel that smokeless, on the other hand, relies on the primer to establish the initial pressure in the cartriage to get the powder in it's fast burning stage. If you just set smokeless on fire, it fizzles.

This I feel is where the real danger of smokeless in muzzleloaders lies. It's not that modern muzzleloaders are too weak to stand target load smokeless pressure, it's that a percussion cap only sets the powder on fire. Then someone will think that he has an underload because it bloops and add more powder until the smokeless burns up to it's fast burning pressure and detonates, destroying the gun.
Weak primers have also been linked to detonations of slow burning smokeless loads in big cartriages.

I understand that 16 inch guns used in battleships are loaded with about 600 pounds of smokeless but the last bag of powder is a bag of black powder right next to the primer to act as a kicker to get the initial chamber pressure into the smokeless powder's fast burning rate pressure.

I discontinued experimenting with smokeless in the ROA, if you have to have that black powder kicker in the chamber anyway, there's no point in it, you still have that cleanup to do. Maybe if someone made a cylinder that used sealed 209 shotgun primers instead of caps it would be worth doing but you still don't have the cartriage's crimp.

[darkgael]

I like that idea - duplexing with FFFg as opposed to a smokeless propellant. I suppose that one could even use 10-15% FFFFg without a problem.
In an effort to use up some Pyrodex that I had on hand, I shot duplexed loads of BP and Pyrodex in my flintlocks. I used 10 grains of BP (ffg) behind 80 grains (volume) of Pyrodex. Went bang every time the rock hit.
Pete

[kraigwy]

It must be possible to mix BP and nitro and still have no safety issues. But where to start?

I know you asked for anything BUT "not to try it"

But I still have to add:

I was LE EOD, part of my bomb squad duties was the policing up of fingers and other assorted body parts from people trying to make their own powder, explosives and fireworks.

Its not a pleasant job.

[hilliard]

Hi Folks,

Thanks for all the reply.

@Kraigwy: Yes I will be very carefull and try not to shoot any bodyparts off.

@Unklenick: I am fully aware grain size has to match or mix will unmix. I think by packing charge tight (use filler). Unmixing can be prevented. Problem with that is you usually do not fill up nitro loads.

@darkgael. I managed to get 71 grains BP in the case. It is not to difficult. Just use a long droptube and compress. The original .303 has a central canal however. It is possible to drill the canal when you first load an unprimed case and put the primer in after that. But driling BP and priming afterwards does not sound like a good idea to me.

@luciano. Cleaning BP faulling begins with flushing with water. Then soap. I tried all the formulas available. No one is 100%. One gun takes at least 3/4 of an hour to clean. If bore already has some pitting even longer. Next day patches come out black again. Leveractions are not easy to clean. But if you have some good advice I would like to hear it.