Originally Posted by 300stw
all loads were shot in a 1.5 hour time frame this afternoon, chrony and shooting bench stayed in same exact spots, overcast the whole time, no acces to anothe chronograph,,,, ,
Then you are screwed...
I have 3 chrony's I can say with confidence all 3 give different readings and all 3 are wrong.
Also I learned, especially with a Chrony, it needs to be at least 18' from the muzzle or the blast rattles the screens and give erratic readings.
Another thought is if you are confident you are only getting 2860 from 73 gr of H-1000 and a 180, I would check my scales.
I have built 3 of these rifles and all were shot with 180 Bergers. I started in the 72 ~73 gr charge with H-1000. In RWS brass, which will require a lesser charge weight due to the redued case volume, 73 gr was well over 3000 in a 29" tube at 4100' asl.
My advice is forget the Chrony, go work up an accurate load at 200 yards. Then take it out to 800 to 1000 yards and find the spot on drops. Ten let the ballistic program tell you the velocity.