A question about powder choices


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napp
January 10, 2011, 10:01 PM
Having just bought my first BP rifle, I'm trying to gather up everything I will need before the first range trip.

Most (but not all) of the recommendations I read for BP in a rifle are FFG. I have a supply of Triple 7 FFFG for use in my revolvers. Do I really need to buy a different powder for the rifle? What are the ramifications of using Triple 7 FFFG in my Lyman Great Plains Rifle (.50 cal)?

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mykeal
January 10, 2011, 11:02 PM
No safety issues; you'll just have to adjust your loads if you ever want to compare them to other powders.

First, granulation: a .50 cal rifle will use fffg without much effect when compared to ffg. fffg will have a faster pressure rise, and a slightly higher one, but the amount of energy released will be the same. Muzzle velocity will be slightly higher than with ffg.

Second, 777: the normal adjustment for 777 is to reduce the load by 15% to get a load equivalent to black powder; that is, 70 grains by volume of real black powder is equivalent to 60 grains by volume of 777 (round up to the next grain).

Third, fffg 777 vs ffg real black: I'd add about another 5% to the adjustment to get the real black equivalent. Thus 70 grains of ffg real black powder is equivalent to 55 grains of fffg 777 (I rounded down this time).

That's all pretty approximate. Things like the thickness of your patch material and the type and size of the projectile will come into play, so don't take any of that as precise and absolute.

In terms of maximum load in a GPR, it should handle anything up to 90 grains by volume of fffg 777 (110 grains of ffg real black); after that you're toying with damaging the stock at the wrist. I also strongly suspect that you'll have nothing approaching reliable accuracy at that load; .50 cal GPR's like more reasonable loads.

moose owner
January 11, 2011, 12:41 PM
Hodgdon's website originally stated that you should use Triple Seven only in a 209 primer ignition system. However, they have removed that warning now. I have used Triple Seven in a percussion shotgun without any problems. It does seem that the ignition times are slower with Triple 7, but that may be more imagined than real. However, you do need to adjust the amount of powder (by volume) down as indicated in the prior post.

Conventional wisdom suggests that FFFg is a little course for the larger caliber guns. However, I know lots of people who prefer FFFg over FFg in their shotguns. Give it a try, you might be pleasantly surprised.

45-70 Ranger
January 11, 2011, 02:17 PM
Like your self, I had some 777 in 3f handy. Tried it in my T/C Hawken I built years ago. This weapon was sighted in at 100 yds. with 2f BP and Pyrodex RS both loads were 70 gr. with a patched RB. Used 60 gr. setting with the 777 and it printed in the same spot. Went to 70 of the 777 and it was just a tad lower. That told me it was a bit faster.

After shooting BP weapons for well over 45 years I feel the loads were more than safe. And the plus side was a super easy cleanup! I'm sure that you'll have a good time with this. Shucks, I even load 777 3f in my .45-70 and it shoot great!

Eade

napp
January 11, 2011, 06:24 PM
Thanks for the replies. I picked up a jug of Triple 7 FFG today. When UPS gets the rifle here and the weather permits, I will try both types to see what kind of results I get.

robhof
January 11, 2011, 08:13 PM
T 7 is picky about compression, you're just supposed to seat the projectile firmly on the charge, the 1st time I used T 7 in my ROA I got slow ignitions and reread the instructions. I was pressure seating the same as with real b/p. When just snugged up, they shot faster and hotter than before with the same loads.

andrewstorm
January 12, 2011, 04:26 AM
I read on the 777 website that the only 777 you should use in cartridges is ffg you should never use fffg in cartridges.:eek:

bp_cowboy
January 12, 2011, 01:54 PM
I use FFg on rifles and revolvers, but I used BP exclusively.

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