Cold Bore Shift

[fredhorace77]

What causes the cold bore shot to hit in a different area than the group does?

I have 2 hunting rifles that do this constantly. One is a Rem700 BDL in .243, the other is a Win M70 Post 64 in .308
At 100yrds the cold bore shot on these rifles are at least 1.5-2" high and right. The next shots land right in the spot I last sighted it into. Both of these guns are wood stock with sporter taper barrels.

I also have a Rem700 LVSF in 223 that has never had a problem with this. Is it just a difference in stocks, bedding, barrel and or barrel stiffness? Or a combination of any or all of the above?

 

[LHSmith]

IME, mostly fouling. A freshly shot bore lays down carbon that is still soft and acts like a lube. If the rifle was put away dirty, that carbon has hardened and affects the bullet differently. Also, heat to some extent in some rifles. However, in my bench guns I've had barrels shoot very close to POA on the first shot, but I always "throw" the first shot away because close is not good enough in BR. Find the right lube regimen to apply to your bore between matches and your number of foulers will be diminished.

 

[pahoghunter]

What causes the cold bore shot to hit in a different area than the group does?

I have 2 hunting rifles that do this constantly. One is a Rem700 BDL in .243, the other is a Win M70 Post 64 in .308
At 100yrds the cold bore shot on these rifles are at least 1.5-2" high and right. The next shots land right in the spot I last sighted it into. Both of these guns are wood stock with sporter taper barrels.

I also have a Rem700 LVSF in 223 that has never had a problem with this. Is it just a difference in stocks, bedding, barrel and or barrel stiffness? Or a combination of any or all of the above?

I shoot in groundhog shooting matches and I can assure you its not always just the the first shot, its not unusual to see guys shooting 5 or more shots until the rifle settles in, some people swear by LOCK-EASE many people that treat there barrels with this claim first shot always in. Good luck

 

[fredhorace77]

IME, mostly fouling. A freshly shot bore lays down carbon that is still soft and acts like a lube. If the rifle was put away dirty, that carbon has hardened and affects the bullet differently. Also, heat to some extent in some rifles. However, in my bench guns I've had barrels shoot very close to POA on the first shot, but I always "throw" the first shot away because close is not good enough in BR. Find the right lube regimen to apply to your bore between matches and your number of foulers will be diminished.

I think you might have just figured it out for me. The 2 hunting rifles that have this problem very rarely get shot, and they always get put up with a dirty dry bore. The lvsf gets shot all year around, though I don't ever treat it with any type of lube I do shoot it at least once a week at some type of critter.

 

[mac37]

Lock-ease... I thought it was Marvel Mystery Oil?

 

[Jose_Luis_G]

What causes the cold bore shot to hit in a different area than the group does?

I have 2 hunting rifles that do this constantly. One is a Rem700 BDL in .243, the other is a Win M70 Post 64 in .308
At 100yrds the cold bore shot on these rifles are at least 1.5-2" high and right. The next shots land right in the spot I last sighted it into. Both of these guns are wood stock with sporter taper barrels.

I also have a Rem700 LVSF in 223 that has never had a problem with this. Is it just a difference in stocks, bedding, barrel and or barrel stiffness? Or a combination of any or all of the above?

If we take for granted that you have cleaned the bore after the last shooting session, I can tell you that the way to avoid it is to do the last stroke with Ballistol Kleber oil, to soak the barrel.
After that, you must run a clean patch -only once, back to forth- to eliminate the excess of oil, and leave the rifle until the next session.
DO NOT CLEAN THE RESIDUAL OIL BEFORE SHOOTING. Just start shooting and you will realize that shots go to the same place where you hit the last time.
Don't care about the mínimum residual oil in the barrel. Ballistol is one of the very few oils that can stand in the barrel when shooting, without making any harm. Of course I am talking about traces, not a soaked, dripping barrel.