7-08 140 grain Nosler Solid Base Mystery

[vtmarmot]

I have two rifles in 7mm-08 that have been shot very little and cleaned properly. The Remington M700 Stainless Synthetic Mountain Rifle averages a little over an inch for 3 shot groups at 100 yards with a variety of ammo (.6 to 1.6 inches). The M700 CDL has always been under an inch for three shots with everything. There is one exception - neither will shoot the Federal Premium Vital-Shok with Nosler 140 grain Solid Base into anything under 3.2 inches. This is not a problem with the scope, the rest, the bedding or the shooter. It is very clearly the ammo.

I bought two boxes of this for a good price. Perhaps the performance explains the price. The bullets mike out correctly. Velocity is as expected. I have practically unlimited reloading possibilities for these rifles, so using what's left of these two boxes for offhand practice is not going to kill me. Still, it rankles. I'm wondering if anyone else has had a similar experience with this ammo?

 

[glp]

Paul,

why get wrankled? I have a Rem 722 .308...you ought to see the variation in both POI and grouping with different bullets....Hornady SST 150 and 165, Nosler BT 150s and some old Nosler solid base with the exposed lead tip. The rifle has a 22" really light taper barrel(whippy I guess). I can dial the scope to POI and we all know that different rifles have different bullet, load likings. The best grouping were the old Nosler SBs.

The thing that wrankles me about this rifle is the amount of coppering. It is massive and it takes a lot of effort to get it reasonably clean. It shoots much better clean than coppered up. --Greg

 

[vtmarmot]

More than likely, the copper fouling is due to roughness in the leade from machining marks. A bore scope would show that. Tubb Final Finish bullets would take care of that, as would hand lapping or fire lapping. If the roughness is "alligator skin" from repeated firing of hot loads, then only an extreme amount of lapping would get rid of it completely. John Barsness said he did that once, but I don't have that much time and energy.

Roughness in the leade causes copper to go into suspension in the gases, and it precipitates out further down the bore.

 

[glp]

I may

give the TUBBS barrel conditioning system a shot with this rifle. Its a nice handy little 722 but shooting deteriorates quickly due to the amount of coppering. I have borescoped it in the past and its just about what you would expect with a factory barrel. Not fire cracked but moderately rough.