Why A question for the technical guys.

I't's my practice to take all the hunting rifles to the range tshortly beforeo shoot one more 'confidence builder' group a few days before the season. At 100 yards I shot six rounds from the .270 to warm up, the one group from the stainless M70 in 7mm Mag, one from the 700 Ti in 7mm 08 and finally one from the stainless M70 .270. I couldn't see the holes from clearly until I measured the groups. The 7mm Mag and 7mm08 both shot >1/2" groups cold and clean. But, as I've noticed in years past the first six shot group from the .270 was about 2" but the second group <1/2". So why, technically speaking, do some guns need more copper to shoot well?

I caught multiple errors in this posting when I reread it this PM. So here are the corrections.


I't's my practice to take all the hunting rifles to the range shortly before the season to shoot one more 'confidence builder' group. At 100 yards I shot six rounds from the .270 to warm up, the one group from the stainless M70 in 7mm Mag, one from the 700 Ti in 7mm 08 and finally one from the stainless M70 .270. I couldn't see the holes from clearly until I measured the groups. The 7mm Mag and 7mm08 both shot <1/2" groups cold and clean. But, as I've noticed in years past The .270 shot better after fouling shots. The first six shot warm-up group from the .270 was about 2" (five shots in 1.5") but the second group about 1/2". I've done better with the gun a few times but @1/2" is average when it's slightly fouled.

So why, technically speaking, do some guns need more copper or whatever in the barrel to shoot really well while others don't?

Not sure, but I do know that competitve shooters let a few "foulers" and "sighters" go downrange before they shoot for record. Sounds like a good question to ask on the benchrest and long-range forums.