45-70 newbie

[Sando]

Hi all, I'm taking my first crack at loading 45-70. I'm using
R-P cases, 405 grain hollow base cast bullets, and home-made blackpowder (75/15/10). For starting loads I'm putting 60 grains in the case, which completely fills the case. I can easily compress the powder and seat the bullet but it makes me wonder. If it's a 45-70, shouldn't it easily hold 70 grains without compressing? For grins, I poured 60 grains of Hogdon BP substitute into a case. That too filled the case to the top. Are 45-70s always going to require compressing the powder? I'll be shooting these with a new Uberti Trapdoor Springfield and don't want to create a $1400 shrapnel grenade. Appreciate your comments.

[NickSS]

BP substitute powders are measured by volume not weight as they weigh less than BP does by volume. You do not say if you measured your BP by weight or Volume so I will assume weight. First if you just pour the powder in it will fill the case fuller than if you use a Drop Tube. BP that is poured in direct from a measure or pan needs settling. Pouring it through a drop tube of 24 to 30 inches in length settles the powder or you can put a tray of charged cartridges on a vibrating tumbler for five to 10 seconds to settle the powder. This makes BP burn better and contributes to accuracy. The average RP case when loaded with 70 gr of BP by weight and dropped through a 30 inch drop tube will fill the case almost to the top but not quite but to seat the bullet you are using will require compressing the powder at least 3/10 inch which is not bad with GOEX FFG. I generally load that bullet with 65 gr of BP Which compresses the powder around 1/18 inch. When loading BP you do not want any air space and some compression. You need to experiment to determine what compression works best in your rifle with the bullet, powder and primer you are using. I generally start by loading a bunch of cartridges with varying compressions. Generally I load 0 with the bullet just touching the powder, 10 with 1/16" Compression, and so on up to around4/10 inch compression. I then shoot them cleaning between each set of 10 rounds and using a blow tube between shots. The amount of compression that gives me the best accuracy is what I use for future loadings.

[Sando]

I measured my BP by weight, not volume. Didn't use a drop tube, just a funnel.

[NickSS]

then use a drop tube or vibrate the loaded shell before seating the bullet with the hollow base bullet I do not use a card wad but with a flat base bullet I do use a card wad under the bullet. If you weighed the substitute BP you got way more bang in the case than 70 gr of BP would have and it might be dangerous to shoot in your TD if you want to use that stuff measure it by volume only.

[Sando]

I don't plan on shooting the BP substitute in my TD. That was just a reality check on case volume, powder volume, etc.

[onondaga]

80-13-7 is the basic firearm formula. 75-15-10 is a low power high stink fireworks mortar blowing charge formula.. Mixing the portions and not binding and kerneling the mixture is a very bad idea. The unkerneled mix is extremely static sensitive and has unpredictable power and stability. I have mixed and kerneled black powder many times. If you were related to me, I would restrain you from attempting it.

Kerneling is completed by placing the mix in a wooden tumbler with copper balls and tumbling for 24 hours or more to reduce particle sizes to minimum and blend them. The mix is transferred to a spark proof container and water is added to make a very firm dough like mix that is pressed into cakes. When the cakes are nearly dry, they are fractured into grains with something like a wooden rolling pin. If you fracture the pieces to exactly FF grain size it will fill a 45-70 case to the brim and the powder will weigh 70 grains.

A disposable out building located far from people and dwellings is required for minimum safety and most explosions occur during mixing, tumbling or when the tumbler door is opened. Remote tumbler door openers and site evacuation are currently in use by manufacturers, plus a myriad of other safety codes.

Pyrodex FF or Goex FF is much less fatal to load with and much more consistent for accuracy.

[Sando]

I'll try 80/13/7 on my next batch 1/4 pound batch. I'm using isopropyl alcohol to make a stiff dough and squeezing the dough through a fine strainer.

[onondaga]

Well if you insist. The other secret ingredient for the batch size you mention is potato dextrin added to the alcohol ( or added to the water ) and then after kernels dry mix in 1/2 teaspoon powdered graphite. You will have stronger kernels that don't clump. If you can't get the dextrin, use wood glue dissolved in solution with the alcohol before mixing. Drugstore rubbing alcohol is usually 30% water and will work but it is the water that binds the ingredients not the alcohol. Pure water actually works better to give you stronger kernels. Alcohol will make the kernels dry faster but it also makes kernels airy and weak for handling and more prone to separation. With very pure alcohol the kernels will break down and ingredients readily separate because no water binder has been used for the necessary binding of ingredients.

You will find applying water with a spray bottle very effective for bowl size batches. The dextrin or glue amounts are based on a one cup volume for your spray bottle and mixed in advance. 1/4 teaspoon dexrin or 1/2 teaspoon wood glue per 1 cup water works well . Just spray only what you need to get the dough consistency and mix thoroughly before using your screen to rice the mix. You may consider removing an equal volume of powdered charcoal from your from the 13 part portion of it in the mix and then the powdered graphite replaces the amount later. Don't use lamp black carbon unless it is oil free ballistic grade, oil will weaken your powder considerably.

[Sando]

Onondaga, How do you grind your KNO3? Mine comes in prill (pellet) form, quite hard granules. My ball mill with lead balls did nothing so I ran it through my grain grinder. That worked perfect, but I'm not keen the KNO3 getting mixed even slighlty with my wheat flour. Also, you mentioned powdered graphite in lieu of part of the charcoal. When do you add that? After the big three are thouroughly milled?

[cajun shooter]

It seems to me that you may remain a newbie for quite a while if you understand my drift. You have never loaded a BP 45-70 but insist on saving $15 to try out your new $1400 rifle. I see that you are also a newbie to the forum with 5 post to your credit. I hope you make #6 You might win the cupie doll for shortest time on forum.

[onondaga]

I am not mixing any more. When I finally found a supplier that provided ball milled KN03, ball milled Sulfur and Air Float Charcoal they were what I used. Ball milling the white stuff takes a lot of time--5 to 10 days. I used a dozen 2 inch glass balls in a tilted 2 cubic foot hexagon wooden tumbler. This would tumble 5 pounds KN03 nicely in one week at 60 RPM. Brass or copper balls are better but elusive.

When all three powders are good to mix, I remove a portion of the Charcoal equal to the graphite portion. After mixing the three, caking and kerneling, last, the graphite is mixed in to the completed and dried kernels.

If you really want good powder either get ball milled KN03 or ball mill it after you grind it. It should be as fine as air float charcoal and so should the sulfur. extremely fine powders are important so that water will bind them during the caking. Don't know why you mentioned Wheat Flour, I have never used that in gunpowder. Perhaps it was a typo for Flowers of Sulfur.

It is good you gave a grinder, I have used prill and hammered it in heavy canvas bags before ball milling.

Pyrotechnics was a hobby of mine for many years, but I gave up the hobby about 10 years ago when I moved to an apartment. The most scary thing I ever made was Fulminate of Silver. My best accomplishment was rocket engines with 1.5 pound thrust. These far outperformed anything you could buy.

[missionary5155]

Good morning
Powder compression is good. And using homemade Black P I do not think you will have to worry about destructive dissasembly of a new Uberti Trapdoor.
Generally Homemade BP is a few steps lower in power than Goex and certainly much less than Swiss.
A good real test would be to load by measure 65 grains of 2F Goex with a 300 grain boolit (or whatever boolit and compressed BP charge) against an equal charge of your homemade BP fired through a Cronograph... then you would have an idea what energy your homemade BP is giving compared to an industry standard.

[Sando]

Wheat flour as in bread making. Totally different subject. Thanks all for your input.

[Freebore]

Posts like this fascinate me. I don't know if I would start one myself, but I really like to read them!