Kevin Cram just finished a 22-250 for me, and (so far) I have expended well over 300 rounds in my testing. The gun has a nice 26” Krieger 1-12” twist heavy varmint barrel on it. This is my second 22-250, and it doesn’t seem to like anything that worked well in my previous 22-250. At this point I have found a solid load for the 40gr. Sierra HP (bullet No. 1385). The best group was 5-shots in .41” (at 100 yards) with IMR-4895, at 4120fps (with an SD of 17.5). 200-yard groups are running around 1.1”. I hope these 200-yard groups will improve when I replace the fixed 12-power scope with a 6.5-20x variable. Yeh, I know… not one of those powders you normally think of for the 22-250, but I have the target to prove it works. I got to this load after trying Varget (terrible), H-414 (great with loads around 3700 fps), H-380, IMR-3031, IMR-4064, and the IMR-4895. I also tried WLR, Rem. 9-1/2, and Fed-210M primers. This gun, with its Anschutz trigger and Tubb’s titanium firing pin, gives me much lower SD’s when I use 210M primers.
I could not find any 50gr bullets that could do as well as the 40 and 45gr bullets until I tried (since it is listed in the Hodgdon data and I had some) IMR-4320. The first group I tried gave me a 5-shot 100-yard group of .64” with the Sierra 50gr Blitz bullet, at 3850fps. That was promising. Prior to this, the best I could do was about .8” using the 53gr MatchKing with IMR-3031. So far this barrel shows a definite preference for short flat-base bullets, although the 50gr Hornady V-Max came close to the 53gr MatchKing. All of the longer boat tail bullets have shown me groups around 1” at 100-yards.
My next batch of 50gr test rounds will have 50gr Sierra Blitz and Hornady V-Max bullets over IMR-4320 (37gr, 37.5gr and 38gr charges, 5 of each). I’ll be trying these at 200-yards on the first nice day.