counterboring

[kjeff50cal]

I have a rearsenaled Mosin Nagant M38, (1944 vin) that was crowned and counterbored. The counterbore is not 1/4", nor 1/2" but 1 1/8"!!! It shoots Hungarian Yellow Tip (heavy ball, 180 grn.) well (2- 2 1/2" @ 100 yards) but groups get larger (4-6") with anything else, even 180 grain yugo. soft points. How much counterbore is too much? And on another vein how do you releave possible pressure points (say that fast 3 times) in the barrel channel of a stock (w/o going totally bubba with Acuraglass). I think part of my problem is barrel heating/stock warping (or maybe a loose nut behind the stock  :lol:  ).

Kjeff50cal

[gunnut69]

Wow!!  That's a bunch of counter bore!!  Still if the rifle shoots well with any ammo the barrel is working OK and you just need to tune a bit to get some other brands-weights of ammo to shoot.  There are a bunch of ways to rmove the high spots in the barrel channel that can cause problems.  Sandpaper wrapped around a dowel, the barrel channel scrapers sold by Brownells and even carefull use of incannel carving chisels.  I really belive the careful use of sandpaper wrapped around a form of some kind is likely the best choice.  I use some neet little rubber sanding forms I bought from a woodworkers supply house years ago.  There are various shapes and several sizes of tubular, all with flat handles protruding along one side.  The abrasive paper is simply wrapped around the proper sized tube and grasped firmly along with the tab being used as the handle.  A size just a bit small will allow high spot removal with no gaping of the wood to metal fit along the barrel channel..