^^ What he said, especially #3 & #4
Edit: I will also a little experience I've had with high velocity loads. Many years ago I bought a 30-378 Weatherby. I remember reading about it and couldn't wait for it to come out. I bought it first year. Factory installed muzzle break, "high tech" synthetic stock, blah, blah, blah. I thought I was the [bleep] walking out of the store with it.
I can't remember how many loadings I made for it but it was a lot, always max or close to max of course. I kept having the same problem: 2-3 shots were good (maybe 1.5"-2" MOA at best) then the 4-5th shots were fliers, sometimes HUGE fliers of 6" or more. At first I thought it could be the scope but for giggles I loaded up some reduced rounds ~30-06/300WM velocities. The results were dramatic. The '06 velocities held zero far longer and cold barrel shots were perfect. It became clearly evident that the 28" non-fluted "sporter contour" barrel of the Weatherby was the problem. The high velocity of that round simply turned the barrel into spaghetti subsequently throwing rounds all over the place when it got hot. I won't even get into the "grenading" Sierra and Remington pills that couldn't stay together. I promptly sold that rifle. It ushered in a new way of thinking for me regarding the "need" for ultra high velocity rounds. The overall point may be this: if you know that the first two shots are spot on do you care about the third or fourth being off? For me it mattered a lot. However, you may not care. Most game drops on the first shot anyway.
Last edited by Fifth; 08/09/11.
