Just passing along a recent experience. A while back I picked up a Lithgow(Aussie) .303 Enfield. I did what I thought was a good cleaning before taking it to the range. My first shot at fifty yards was centered well and high.but the bullet made a keyhole. This raised some concern. I tried out at 200yds. figuring I would hit paper and make some slight adjustments. WRONG No matter what adjustments I made I could not hit the 3'x3' backer sheet, let alone the target. I thought I had finally got a real clunker. Decided to do a super duty cleaning on the barrel even though it looked good after the initial cleaning. Let it soak over night with Hoppes and patched it dry, then used shooters choice with superfine bronze wool and JB paste seeral times with patches in between an amazing amount of crud came out. Did some more lighter duty final clean up until patches were clean. Shot it this weekend and it is doing about 2-1/2" at 200yds. If you get a rifle you like at a good price and it does not shoot well sometimes a little extreme care is called for. I figure the grooves had an accumulation of dried on grease or severe carbon buildupthat normal cleaning could not take care of.