My point is, does anyone know of this being tried on a gun in good condition to see the results. Does anyone know of test being done. I suppose it could be like adding a compinsator without th holes.
There really isn't any good reason to counterbore a non-military rifle. If for some reason the rifling gets banged up or wore down, its easier to just cut a 1/2" off a barrel and recrown, this is somethign that can be easily done at home with satisfactory results.
Military rifles were usually counterbored in order that the sights wouldn't have to be moved and reregulated and the last inch or so of a barrel was usually where a bayonet was mounted, except in the case of the M38 MN.
I've tried to counterbore a badly worn M44 once, but ended up botching the job. I ended up cutting about 1/2" off the barrel and cutting a new crown which did improve it a bit.
Another thing to think about- if a barrel has had enough use to necessitate a counterbore, the rest of the barrel is probably chewed up by corrosive ammo and the lands are more than likely rounded off at that point also. I also have a counterbored M38 which I currently consider a wallhanger- it won't hit a sheet of typing paper at 50 yards consistantly, 3 out fo the 4 mosin nagants I curretnly own don't shoot much better, but I have non-counterbored 91/30 that shoots respectably well.