Shooting BP (TripleSeven propellent, actually) in various .44 mag Blackhawks (4&5/8" and 5.5" bbl lengths) recently, the rounds were hitting about 6" high from point of aim at 25 yards.

But factory Rem and Federal full tilt rounds shoot to the sight's point of aim with both BH's(well, generally anyway).:rolleyes:

This is the first time I've tried something besides smokeless in my BH's, but have shot cap&ball with Pyrodex, Goex, etc.

Is my theory correct that smokeless rounds have the bullet away before recoil affects (or induces much) muzzle flip?

My grip seems consistent to me. This was all in one session a couple afternoons ago.

The whole discussion of the effect of recoil on POA is a hot and heavy topic on many forums. Basically, though, recoil effects start at the moment of ignition and have affected the shooter long before he or she notices anything at all.
BP burn rates are determined by grain size - your question is a good one. I wish that I had an answer for you.
Pete

Welcome to the forum Steve. Rules are simple, be nice and join in.

Like Pete I'm not a black powder guy, but powders like Triple 7 are not black powders they are modern substitutes with simular, but different characteristics. I'm hoping that some of our black powder guys will chime in here and educate both of us.

Thanks for welcomes and advancedly for info.

I have enjoyed BP and like propellents before, but never before had a chance to observe the difference in cartridge form in an otherwise "modern" piece where I could A/B the results. Kinda surprised me!

The really strange thing during that session the other day was how much better my carbine did with BP type propellent, vs smokeless commercial "Cowboy" loads. I can account for that because I believe bullet size was different, so the carbine seemed to group well and close to POA with the handloads (.429 vs possibly .427 for the factory stuff). I guess my old Navy Arms '83 replica "trapper" likes 'em bigger.

Maybe it's time to invest in better calipers (or new glasses). I can't quite tell whether the .44-40 Blackhills are .426, 427, or 428. The handloads are definitely .429-.430. Oh well.
Lots to learn, now that my learning curve has got more obtuse with age.

I always used to think that black powder was a much quicker burning propellant than smokeless, simply because if you throw a match into a pile of black it just explodes in a cloud of white smoke. Smokeless burns quite slowly.

I could never figure out therefore why pressures were always lower with black, and it's generally safe to "just fill the cases up". That seemed to be the reverse of everything I knew about pressure curves compared to burning rates in smokeless.

Apparantly, and this is what I was missing out on, when black is ignited under pressure, as is the case in a gun, it burns much slower than smokeless. I think slower than just about any smokeless powder, actually. I believe smokeless powder also burns a lot quicker under pressure than it does when lit out in the open air. That's why BP cartridge shooters sometimes use duplex loads, with a small charge of smokeless sitting on top of the primer to help burn the black more cleanly.

So BP loads should definitely be going a fair bit slower than full house factory loads in a .44 mag, and perhaps the muzzle flip does have more of an effect on shot placement?

Just my 2c

What I do know is that BP is classified as a "low explosive" and smokeless propellants are not. Despite the fact that they both go BANG when ignited in a firearm, technically, smokeless doesn't explode at all but burns at an extremely rapid rate. The rate of burn is controlled in a variety of ways - discussed fairly thoroughly in manuals - producing many different propellants (remember that they are all based on nitroglycerine or its cousin nitrocellulose). The propellants are different enough that they cannot be interchanged in many(even most) cases.
BP is, for the most part undifferentiated; the formula for it is basically the same (75% potassium nitrate, 15% Charcoal, 10% sulfur) for any grade. As mentioned, the only differentiation within a particular brand, like Goex, is grain size which, since BP is surface burning, controls burn rate. ML shooters commonly substitute BP grades in cartridges and MLers. If I don't have FFFg for my pistol, I can use FFg; it may not shoot quite as well but it will work and be safe. I can use Fg if I want, but with each move to coarser grain the gun will be less efficient.
BP deflagrates so rapidly that it explodes, even when unconfined, yet the explosion is of such a low order that relatively small amounts of energy are released (compared to smokless). Does that mean that it burns faster than smokeless? In the open air, I'd say "yes" BP burns faster but that's not the point. What happens inside a cartridge or a ML chamber is very different. The burning characteristics of smokeless are radically different under pressure. If I had to guess, I'd say that smokeless propellants, confined in a gun, burn faster than BP. Then, again, would a 100gr charge of a heavily retarded smokeless propellant like H870 burn faster than 100grs of FFg BP? That's one of the things that I don't know.
Pete

Good discussion so far. Fascinatin' in fact.

My intuition says BP is slower because I remember the slow "push" of recoil and lower report from ball&cap revolvers, vs the snappy recoil with a modern handgun and smokeless.

Yeah, I remember putting a a tiny amount of smokeless in first against the nipple helped ignite Pyrodex P. Lots less misfires. Eventually I started putting some FFFF Goex instead of a tiny bit of W231 near the nipple.
I bought the 4F Goex to try in the frizzen of a flintlock because BP was getting hard to find, but it sucked as frizzen powder.

In years past I used to shoot a flintlock a fair amount when Pyrodex first came out. I found that about 10 grains of 3F in bore before you added pyrodex P worked nicely and had no ignition problems. Personally I have never mixed/duplex loaded smokeless and BP or Pyrodex and I have no desire to try it either

One word of caution; FFFg Triple 7 is not to be used in cartridges. If you are using that granualation you may be getting a dangerous pressure spike.

Pressure tests show black powder creates higher initial pressure but smokeless has a longer duration giving it more pressure toward the end of the burn. Normally, we think of BP making 15-20,000 PSI. But under some circumstances can generate upward to 65,000 PSI.
Empty space in a cartdidge is fine for smokeless, but not in Black Powder.
The open-air burning of powder really does little to show what's going to happen inside a cartridge or barrel.

One word of caution; FFFg Triple 7 is not to be used in cartridges. If you are using that granualation you may be getting a dangerous pressure spike.

Nah. FFg. 'Bout 1/16" compression when mounting a bullet to a full case. Shoots well, feels right on recoil. Just throws high verticle strings from POA ( 4 - 6" at 25 yards).
The smokeless (H110 and w231) loads drill the target center (POA) and group much closer.