Re: What are your cold bore POI shifts?
Hootie,
If my barrels are fouled but cold, I have zero cold bore variance vs. follow up shots all the way up to when mirage from my barrel heat starts blurring my view through the scope.
If my barrels are clean, the clean/cold bore shot is almost always slower by roughly 75fps. My cold bores inside 200 yards are in the follow up group as you just don't see the velocity drop on paper at close range. 200 and out will almost always let me drop the cold bore low at 6 o'clock. Shot 2 will be very close and #3 to infinity will be at normal velocities and P.O.I.
My experience is that the more rough a barrel is and the more stress it holds, the more picky it is during all of this. Factory barrels, even on the high dollar rifles almost alwasy move as they warm and cool. Luck of the draw will also determine how rough that bore is. A clean bore that has rough spots will have significant P.O.I. changes between the first 5 shots after a good cleaning even if the barrel cools completely between shots.
Capt. Huskey prolly can share a ton on this topic as he has done more statistically valid record keeping on such issues.
