Screwed on a new 1:8 pbb, 22" barrel on my Tikka CTR last night and loaded some alpha srp brass with superformance from 38.0-42.0 in .5 grain increments with 77 tmk and cci 450 primers. It's sprinkling rain today and about 40 degrees. I experienced delayed ignition on every shot. I have some h1000, h4350, imr 4350, retumbo, and a handful of other powders in hand but no 4831. Any suggestions on what to try, or should I just order up some lrp brass? My srp collection is heavier than my lrp but I'm not about to run out of either.
Edit: I switched to h4350 which eliminated the delayed ignition. I started at 38.0 and went to 42 grains in .5 grain increments. Midway through I started getting slight primer cratering and faint intermittent swipe.
I then loaded 5 at 39.5 grains and threw them in the freezer for a while, no problems, with a sub moa group. I'm going to run with this load and swap my thermal over to this rifle.