Re: 22-250 remington
I have tried every powder suitable for the 22-250 in the last 35 years and I keep coming back to H-380. My rifle is near 8000 rounds and still shoots .250" MOA. I use CCI-250 magnum primers. H-380 needs a magnum primer for consistent ignition. The power is temp sensitive but never minute by minute. If it starts shredding bullets or showing signs of pressure I just back it down a grain or 2. With 50 grain bullets I use 38 to 42 grains depending on the weather.
Try 50 grain V-Max's, SPSX's, Sierra Blitz Kings, Nosler B-Tips or any other non target 50 grain bullet. I never have had good luck with Berger's, Speer HP Match or SMK's in the 22-250.
My Ruger 77V 22-250 is one of my most favorite rifles. I could build myself any custom creation I want for shooting digger squirrels but I just love this Ruger. It doesn't like bi-pods either. I just shoot over a bag or stump, a hood, out the window, over the bed and kill squirrels like a guided missile.
Build a man a fire and you heat him for a day.
Set him on fire and you heat him for life.
Only accurate rifles are interesting.
Gordy and Brady.