Is 777 safe to shoot out of a kentuckey long rifle? I know people do but is it safe even with the 15% reduction in the measurement?

If the rifle is a flintlock, don't waste your time. You would have to duplex the load.

Out of a percussion cap rifle, I shoot Triple Se7en all the time. And you're right, cut the charge 15% from normal. If you're shooting patch and ball and find the patches are burning up... put a wonder wad between the powder and patch and it will solve the problem.

Triple Se7en 2f will work just fine.

When you say duplex the load, are you talking about it would have to be 'primed' with real black powder that would ignite the T7?

Yes.. when I was testing different powders in my flintlocks, I had a terrible time getting them to ignite. If you dump even 10 grains of Goex 3f down the barrel first, then tap the butt of the rifle on your shoe to level the load, you can then load the other powders and they are much more dependable with ignition.

I'll second that, for 777 to go off in my Lyman flintlockI found it necessary to drop 10 grains of 4f down first (ideally 3f would be better but that's what I had)and then load the remainderof the chargewith 777. Worked reliably when done so, forget it if not. I will add I've since gone to 2f BP and can tell you that 777 is a helluva lotcleaner, I cannot believe how filthy the bore is with BP. To me the extra couple seconds to load vs. cleaning every shot was worth it. Maybe I should try 3f BP?

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SDure, it's safe enough. But I've had difficulty shooting PRB with it-the stuff blows patches even with substantially REDUCED charges.

But it shoots GREAT in my .45 Hawken caplock when used with a Maxiball and a WonderWad!

If you're shooting Triple Se7en and getting blown patches, try adding a bore button between the powder and the patch. The bore button will take the brunt of the explosion when the Triple Se7en ignites and your patch will look almost good as new. Also it should not effect the accuracy, but you would have to shoot it to make sure it has the same POI.

Another method you can do if you have no bore buttons, a.k.a wonder wads.. is to add 20 grains of corn meal on top of the powder charge, and then seat the patch and ball on that. Before you drop the corn meal down the barrel, tap the rifle on your shoe to level the load, then dump the corn meal. It actually works very good and the corn meal seems to have a cleansing effect of sorts on the barrel.