Originally posted by Markwhiz
Well, I finally got back to the range to do some more extensive testing with my can of BM3.
Overall, out of my 22" Knight USAK, I can say I am unimpressed.
The stuff is VERY clean, but at least in my circumstances - that is the best compliment I can give it.
Testing a full range of sabots, conicals, and patched ball I found:
1. It takes 15gr more BM3 powder to equal the velocity the identical bullet gets with 777 powder. Dropping a load just 5gr below that mark drops the speed approx 100fps and about 3" on a target set at 75 yards.
2. My groups with BM3 are over double the size of my best groups with 777 at 75 yds. The BEST group shot today with BM3 was 2.2 inches, with most of them between 3 and 4 inches - while my 777 loads would cut .85" groups with the same bullets.
3. Also I found that it did very wierd things to the powercheck cups on Powerbelt bullets. Even though I lube the bullet posts and make sure the cups are loose on the bullets, on about 1/3 of my powerbelt shots the cups failed to disengage from the bullets - ripping huge holes in the target and really putting a whammy on accuracy. And several of the cups I found after firing showed that the skirts were cut pretty badly and the center hole the post goes thru were expanded to over twice the size of the original hole. I have had problems with the skirts not dropping off when trying them with 3fg 777, but I've never seen the cups damaged so much with 777, Pyro, or Clean Shot.
I to summarize my findngs, I think BM3 is pretty powerful, but shorter barrels like mine can't take advantage of it's burn rate unless you push the powder charge to levels that affect accuracy. So for now, 777 will remain my powder of choice for this rifle - I think I'll use the rest of my BM3 to teach my future stepson how to shoot...............the cleaner shooting will make it easier for him to get the hang of operating the rifle.
