I got my barrel in today to start on my Chambersburg School Rifle. I am building a flint 45 cal. It is a GMB with. I had them install the breech plug and match mark it and then take it out. A couple of questions about this as to starting this rifle. 1) The breech plug when screwed in finger tight, is only one flat off from the match mark. Doesn't this sound a little off? 2) While making this gun, what do you us to treat the inside of the barrel while working on the rifle through it building process? 3) I also notice that the lug on the breech plug is almost perfectly square, and by looking at guns during building, all I have seen seem to be tapered toward the bottom. Is this something that has to be done, or inlet it in as it is?