starting load for drilling

[fffffg]

does 21 grains of 4198 sound right for a drilling starting load with 200 grain bullet,20-1 lead /tin,with gas check.... .360 bore, 8.7x72r.. nitro barrels, the case capacity is 60 grains black powder. and 10 grains of unique shoots ok in it.. maybe chrographing the unique load would tell me something?? the unique shoots 2-3 inches high at 105 yards, in about a 4 3/4 inch group with .361 bullets with 30-1 lead.. .. dave.

[John Traveler]

That case capacity of 60 grains black powder and the .360 bore size brings your cartridge close to .38-55 Winchester capacity.

Per previous postings, I would start with and stay with starting loads for the .38-55 using that 200 grain bullet.

Since that 10 grains Unique is a safe, light load, the 21 grains IMR 4198 would be safe as well.  Since you are starting with light loads, it's best to avoid using ball-type powders for this initial testing.

[fffffg]

Thanks traveler..   i just got a post from another site, and he said ross sayfreid gave loads of  4198 that would be  40 percent of black powder loads.. that would be 24 grains of 4198. and my gunsmith gave the ok to 21 grains, it seems everyone is agreeing on this and that is a big point to me.. no use blowing up a gun that took someone a year to build in  1926..  thanks.. dave..