Factors Affecting Accuracy With Modern Replacements For Traditional BPs

Retrieved: 12/12/2014
Last Post: 04/07/2006

With this topic I am hoping to learn the most important factors, inherent to the powder itself, that affect group size when using one of the modern replacement for traditional BPs. As you will see, this thread builds on previous ones concerning the need for "no air space" in BP cartridges. Uniformity in burn rate is the factor I emphasis initially. Are there other major factors?

Hopefully, this discussion will keep separate the "subs" that are basically altered traditional BPs, that is Pyrodex and 777, from those that are based on quite different chemical componds and reactions, that is, APP and APP Gold/Goex Pinnacle. I only have personal experience with Pyrodex and 777 because the APP powders are not sold where I buy powders.

I will start with a quote from a recent post by Dutch Bill. I have bolded the part that seems most important.

"The bp subs rely more on chemical reaction rates than does black powder. With the subs you simply have ground ingredients being agglomerated into what passes for powder grains. No densification, graining and polishing as with black powder. How reactive the ingredients are with each other plays a major role in combustion rates and how uniform the combustion will be."

The first thing that struck me when I opened by first cans of Pyrodex and 777 was that the powder is in "fluffy" lumps rather than the nicely polished and glazed grains of premium BPs or the well defined grains of nitro powders. The second is that the powder really does look like it has had its density "fluffed" so that it can be closely loaded "volume-for-volume" for a standardized, hypothetical traditional BP.

QUESTION: Could the performance of either of these powders be improved (more uniform burning) if the ground and mixed chemicals were pressed/formed into uniformly shaped and sized grains? That is, if Hodgdon would produce the powder in regular grains.

Hodgdon already does this with their pelletized Pyrodex and 777 and APP also sells pelletized powder. So, it seems on first glance that production of finer grained, pelletized 777 and APP is technically sound.

This would, of course, eleminate the "volume-for-volume" loading. For many of us this would not seem to cause a serious problem, especially if the powder volume need not rise to the base of the bullet. It seems to me that the large volume of air now trapped within the "fluffed" grains would now be largely (but not entirely) dispersed as with nitro powder loads filling the same volume (assuming same grain sizes, shapes, etc.).

Dick Dastardly
April 06, 2006

I'll add another question. When loading heathen smokeyless fad powder I do it by weight, not volume. Might it not be a similar situation with replica powders? Then those "pellets" and other compressed forms could be easier to recon with. Maybe not a stand alone answer, but one that might assist in finding a good beginning load.

Lars
April 06, 2006

Nearly all of us that value small groups, total reliability, totally consistancy, etc. over everything else weigh ALL powders, no exceptions. I started reloading with a powder scale, am sure I will end my reloading days with a powder scale.

Powder measures and dippers are a convenience, no more, no less. When I use them they are checked often against a scales, often on every round of ammunition. My scales are checked against standard weights. SOP.

w44wcf
April 06, 2006

As you know, I have used Pyrodex, 777 and APP in my .44-40 '73 Win circa 1882. My favorite is Pyrodex in this rifle for two reasons, 1.) It smalls more like b.p. and 2.) I get throat leading with 777 and APP and none with Pyrodex. My alloy is W.W. + 2% tin which may or may not be a factor.

I used compression with Pyrodex and APP and a capacity load with 777.

Accuracy with all three was good at 50 yards with 10 shot groups in the 2 to 2 1/2" range which is pretty good from my rifle which has a rough bore.

I found that primers were a factor, at least in my rifle. With Pyrodex, Magnum pistol primers gave the best groups, with 777 and APP, standard primers worked the best.

The biggest factor was the bullet. The tried and true .44-40 bullet 427098 shot the best. The Magma 200 gr.RNFP that shoots very well with smokeless, for whatever reason, produced groups that were 2 to 3 times larger.

Regarding your question, "Could the performance of either of these powders be improved (more uniform burning) if the ground and mixed chemicals were pressed/formed into uniformly shaped and sized grains?". Pyrodex Select is a fairly even grained powder. In shooting it against Pyrodex RS, I did not see any difference in group size, at least in my .44-40.

I have not tried the pellets in my cases, but I remember reading that Mike Venturino (I Think) tested a 30 gr. Pyrodex pellet in the .44-40 and, as I recall, it shot just as well as a case full of powder, even though the pellet was rattling around inside the case.

Lars
April 06, 2006

I too get throat leading with 777 FFg, however, I only see it when I run the first patch down the muzzle and out the chamber -- it does not remain stuck to the bore, presumably because it was deposited on the powder fouling rather than the metal. The amount does not seem to increase much with greater numbers of rounds fired. Like you, I don't see much, if any, effect on group size, even at the end of the day. The bullets have been Meister hardcast, hardwax lubed. Never see that with softer bullets, especially with pure lead bullets.

I got best groups with Pyrodex when using Select, but, only very slightly better than with Pyrodex-P. Since I was shooting C&Bs a lot, I just bought Pyrodex-P for everything. Never tried RS in that 44-40 rifle. Bullets were 427098 and a 240 grain SWC from Mid-Kansas Cast Bullets, both with SPG lube. Both loads were among the best I ever got from that rifle, right up there with the Swiss powder loads from Republic Metallic Cartridge, Co.

I too found mag primers (CCI350) best with Pyrodex and have used them for years with all powders in 44-40 and 45 Colt. Will try some regular primers with 777 FFg when I do my next careful load testing this fall -- probably need to get some high quality 427098 bullets for that test.

Yea, I was impressed with the uniformity of the "grains" of Pyrodex select, but, not much more than with those in Pyrodex-P and 777 FFg. Since I went to heavy compression with Pyrodex early on, I quit being impressed with the uniformity of the grains, they were all gonna get some extensive fracturing. Since I am not compressing 777 FFg much at all, sometimes absolutely none, the uniformity of those "fluff" balls could be important to the excellent groups I get from most loads.

Yea, I recall Mike V. having done that. In addition to your previous threads, THAT kinda knocks the "no air space" mantra in the head for Pyrodex. Perhaps for other BPs?

I may give the 777 pellets a try for group size. They are way too expensive for monthly matches but, might offer an advantage for important matches having small targets at longish distances (about the only major matches I go too anymore). I am always shooting for "clean" matches and really hate to waste even a single shot on misses.

TAKAHO KID
April 07, 2006

Can't help you with this thread. I started many, many years ago with a kit built Muzzle loader shooting real BP. I did use Pyrodex for a while but only in C&B's and that old muzzle loader when I lost a convienent source of the real stuff. Unfortunatly , at the time I wasn't into percision - just making noise and smoke and collecting a little game for the table.

I am going to sit back and listen and learn on this one.

Lars
April 07, 2006

Most everyone benefits from watching and learning, for some of us it is a constant activity. Sure beats being one of those "I know it all already" folks, with heads firmly "ostriched" into the sand!!

What has been really nice here recently is the wealth of solid technical information from very insightful tests done back during the late 1800s when technology and manufacturing were already highly advanced. Today we have the facinating mixture of preserved late 1800s high BP technology (Swiss) still in use and diverse modern formulations of smokey, bulk powders (modern BPs) giving high quality performance (777). Must be rather like in the late 1800s.

Perhaps only one aspect of the technology for manufacturing and testing smokey bulk powders has improved since the late 1800s, that is the peisometric methods of measuring chamber pressures.

Major advances in design and manufacturing of firearms, powders, bullets happened in the latter decades of the 1800s and are still with us today. Just about all modern firearms designs have their roots in those decades. The old world of the muzzle loaders was surplanted by the diverse world of the cartridge guns and their much more diverse and advanced technologies. I am always facinated and educated by the many technical advances in firearms acheived then, things we still use and rely on today.

My reloading and BP shooting started with a 32-20 Winchester Low Wall, a late 1800s all-purpose loading tool (everthing from depriming to bullet mould). The rifle was used for small game, including foxes, out to the limits of group size for first shots (about 150 yards). Precision was everything. The one-shot kill was the standard. Still is for me.