How do you know it's a barrel issue?

[dsbw]

Started shooting my 6 x 47 Lapua last week, 1 in 8 twist, Border barrel, 28". Barrel had 360 shots through it, was re-chambered. I am shooting two or three shocking groups, then a hummer,6 to 8mm) or better, then it goes bad again.

Question? Seating depth, load, pilot error, barrel, where should I start looking? I'm shooting 107 SMK's.This very same barrel was, and still is capable of very satisfactory groups, so where's the problem?

 

[Forum Boss]

Did you check the flash-holes on the brass before loading. The first lots of brass had some % of cases with a little quarter-moon sliver of brass that occluded the flash hole.

What powder are you using and what's your velocity?

 

[dsbw]

I did not check flash holes, I usually do not spend time on them with Lapua brass.Speed is in the 3100"s, average right on 3120.

I am simply dumbfounded that it can do a really good 6 - 7mm group, and then go completely of boil??

More help would be appreciated!

 

[Spotcheck_Billy]

Scope?

 

[steveyrock]

check the flasholes with a jewelers loop or magnifying glass.I got 300 6.5x47 cases and most had to be reamed.