Re: cold bore shot, how long ...
Ok, obviously there are "some" rifles out there with cold bore shifts... what could they be:
1.) mechanical cold bore issues
2.) clean bore issues
3.) heat effects of the chamber/ammo
With some powders, I think we should all agree that hot cartridges impact higher than cold ones so, with older powder leaving a round in the chamber will absolutely impact different than your cold bore shot.
Also, a clean bore is physically different than a fouled one so, that's not a hard sell for me either.
Now, the big debate is all about mechanical changes or the possibility of them. In my own rifle I have a trued action etc. I also have a poi shift from first shot of the day to the second and it is now .5 moa low and .5 moa right with amax bullets... it's .5 moa high and .5 moa left with smk bullets.
I'm going to throw out a theory... what if it's because I am currently using a button rifled barrel that can not be as stress relieved as say, a cut rifled barrel. A cut rifle barrel does not have to be stress relieved in the first place so, could that be the issue? I personally think it probably is. After all, this would be a mechanical shift in where the barrel would be pointed downrange... a small one but, I believe it is possible. My new barrel won't be button rifling so, I'll know in the next couple of months if that is the issue with my rifle. Hell, I may be overcompensating by buying a #10 MTU contour for my next barrel.
And, before anybody says it's me causing the impact shift... I know how to shoot a rifle and, I've been doing it a long time... if I can make the president's 100 with a 4.5lb trigger shooting service rifle, I can shoot off a bipod with a 1lb trigger with a muzzle brake.
There is an undenyable poi shift in the very first round downrange in my rifle and, I do believe it is caused by a button rifled barrel that must move just a tiny bit after the first round of the day.
Honestly, it's not that big of a deal since it's very predictable in where the first round will go every time and honestly, .5moa isn't that big of a shift in the first place but, it's there.
I'd put money that it's the barrel. It's a lothar walther 26" 1:10 spin barrel. I put about 1200 rounds down range with it last year and it's beginning to open up a bit... it's not always shooting .35" groups anymore... Can't wait to post what I find with the Kreiger.
Of course, as with anything as complex as building a rifle, I'm sure it could be several things. I'm having my gunsmith have a look over the rifle when he gets it... he'll have to re-bed the rifle with the new barrel... at least the part in front of the recoil lug anyway.
