Well, I had about given up on the Sierra 70 HPBT MK. But, my very 1st group with 43.5 grns of H414 netted me a 5/8" group. Went back today and my 1st 3 shots with 44.0 grns of same netted me a 1-1/4" group???!! The next set of 3, at 44.5 grns, gave me a 7/16" group! Go figure.
It seems the rifle likes this powder/bullet combo. Not the best groups, but, it does appear its capable of shooting this bullet and these were all with new, FL-sized brass. I'll repeat these after running them through my Lee collet die.
One stupid question - I've been reading this book, "Precision Reloading and Shooting", by Sinclair. It suggests starting a range session with a couple of "fouler" rounds. What's the deal and could that be a possible reason why my 1st three shots gave me a bad group (I didn't shoot any foulers)?