pyrodex to 777 whats the change?

[old fart]

i have decided to change from pyrodex powder to 777 powder, i now use 80 grains of pyrodex. if i use 80 grains of 777 how will my bullet impact change?, i don't want to use too many shots as powder and bullets are getting higher all the time. i now have my optima shooting dead on at 100 yds with pyrodex, i checked with hodgen and they reccomend dropping the charge down to 65 with 777 to make bullet impact the same. i would like to know from ya'll that have made the switch to 777 and how ya'll did, it seems 65 is a little light and besides my measure only goes in 10 grain increasements so i could drop to 70 if thats true. thanks for any help.

 

[mykeal]

I have switched from real black to 777 and back again using the Hodgdon recommendation of 15% less 777 to get the equivalent velocity of Pyrodex or real black powder. At 50 yards I found no appreciable difference in POI with patched round balls from a .50 sidelock.

70 gr of 777 would be a good approximation of 80 gr of Pyrodex, assuming the equivalent grain size also. (fffg=P, ffg=RS). I doubt you could tell the difference in POI at 100 yards.

 

[Mark whiz]

The 15 gr drop in volume when going to 777 from Pyro seems to be right on the money. I've found in my Knight that 80gr 777 cuts the same hole as 95gr of loose Pyro RS and 90gr 777 does the same as 105gr of RS.