[QUOTE=bkbville;691802]Dromia - I've sort of been down this road.
When I try to slug this rifle the progressive twist takes it's toll on the engraving - the changing pitch removing the engraving - so by the time I get the slug out the other end I have no indication of the actual groove side.
QUOTE]
..............JUst drive a slug part way into the breech. Enough to guarantee engraving. Then drive one into the muzzle.
..............Buckshot