I just shot a 3rds group in my 338LM (with an 28inch barel) using the Black hills 300MK ammo.My crono gave me 2975,3007 and 3042 fps
12 feet from the barel(factory gives the velosity for that roond at 2800fps)
and i had stikey extraction (the bolt neaded some good efort to open in the last 1/4rth of the travel) is that normal?
thanks for any responses.

Given that the factory velocities were from a 26" barrel, and that about 25 fps would be gained per inch for 2850 fps out of a 28" barrel, you are 150 fps over the factory (presumed maximum) load, and that suggests an overpressure, unsafe load, confirmed by your sticky bolt lift. I suggest you call Black Hills and report your problem.

I have had trouble getting data with my chronograph that close to my .338-.378. Apparently the muzzle blast bothers the chronograph.

That is a very VERY hot load. I have not gone beyond 2840fps in my 31.5" barrel due to first signs of sticky bolt. It�s time, not to walk away, but to run! AKI