So i wanted to try out some 50 gr sierra blitz kings in my 22-250rem 1-14 twist, a buddy gave me some to try. my best group was .2" of 4 shots and my worst was .5" 4 shots out of 7 diffrent charges. Loaded with H380 and CCI BR2 and lapua brass. The .2" group was with 38.5grs and a average velocity of 3580 fps out of a 20 inch barrel. The other node was at 40-40.5 bit is to hot for my liking. Not to shabby. Heres where i am confused, this is a polyomer tipped boat tail BC of .248 and length of .77" and every stability calculator i used said it had a stability of .92 and expect keyholes and terrible groups, optimal twist of 1-11". These are by far the most acvurate bullet this gun has ever shot. Did i miss something?
I think bearing length affects stability. It probably isn't in the calculator.
The Sierra manual gives the following.
They tested 40-60 gr bullets with a 14 twist
63 & 65 gr requires a 10 twist or faster
80 gr requires a 7 or 8 twist
Sounds like you have the correct twist. The results tell the story.