Xxtavixx
Lil-Rokslider
allow me to elaborate. maybe i can get some help here.
257 weatherby mag. the MarkV. fairly low bullet count. always accurate. i was shooting bread/butter norma bullets into a 3/8th group. got home, quick bore snake. waited for my hunting bullets to arrive from MIDWAY. they got to me fast!! back to the range.. 100gr Barnes TTSX. first shot went right where i expected...then things got wild. 2-3" groups. less of a group, more shotgun pattern IMHO .
i took out the norma lead ammo..WOW..also a wild group!! i packed up. range guy thinks my barrel was dirty to begin with ,but the lead ammo is super forgiving. first copper round fouled the barrel bad. that is his theory. he said copper bullets need a clean barrel to start with.
thoughts?
Once you cleaned the barrel, you might have changed how it reacts to certain bullets. That's exactly why I clean as much as I do, I want the barrel to pattern under it's "normal" state which is pretty clean. I'd suggest a copper foul remover, as well.
FWIW, I had a Mark V and it was super sensitive to being clean, being too hot, what ammunition it had in it and the wind direction. It eroded my confidence in the firearm and I sold it. It was a gorgeous rifle.