Is a 100 grn load of 777, under a PRB, safe in a .54 cal Lyman Great Plains Rifle? Thanks-

Give Lyman's tech a call, 1-800-22-lyman. In Lymans "Black Powder Handbook & Loading Manual" they list loads for black powder, pyrodex, and clear shot. I would not want to assume that any of these loads are interchangeable with 777 without giving them a call.

While you've got them on the phone, order a copy of the above book. You will be glad that you did.

If it is ok, you will most likely want to use the 3Fg. T7 is harder to ignite than most powders.;)

Thanks 8iowa, I called them and they stated that they dont recommend 777 because it is a "synthetic powder", and frequent misfires occur with it. They did tell me that they recommend Pyrodex, and the rifle's max load is 100 grns FFF or 120 grns FF. I've been shooting 60-70 grn loads of FFF777 out of it and had no misfires, (about 40 shots) but I know 777 is a little more potent than BP/Pyrodex, so I want to be cautious. I think I'll consider 75grns the max. Normally I'm not concerned with "how much powder can I stuff in this", but my POI needs to come down, and I've been adjusting speed to bring it down.

Just keep in mind that the folks that make 777 recommend downloading 10 percent from recommended black powder loads with 777. If your shooting it I would recommend going to the musket caps instead of the standard caps. I always got consistent ignition by doing that in several muzzle loaders.

fatelvis:

If there is potential for mis-fire, and the Lyman technicians should know, as they have done more testing in this field than anyone, I would not use 777. Let me tell you, having a load down the barrel that won't fire is a problem that you don't want to have. This happened to me once and I had to take the rifle to a gunsmith to have the breech plug removed, as I did not have a barrel vise.

Personally, I would stay with loose powder in 2F, either the real stuff or pyrodex.

i have a question about the GPR. are they different than say T/C hawkins or the many other b/p`s out there that can shoot loose777. i`m not being sarcastic but i don`t have experience with the GPR. I`ve shot many different synthetic powders out of traditional and inline rifle`s . had my share of misfires which were usually cured by as faucettb stated "going to hotter ignition". on the misfires i`ve had could usually pull nipple and prime flashhole with powder, re-inst. nipple and fire. there have been those times when i had a brainfart and forgot the powder all-together. used a ball puller or compressed air to extract ball. as faucettb stated "if you use loose 777 reduce by 10 percent". again i`m not familiar with GPR:confused: