I got the tools in and tore it down. and gave most certainly not a target crown . It was washed out and not well polished. I no longer have access to a lathe so I sent it home with a gunsmith buddy I trust to recut it and polish. Bore scope did not reveal any problems but he was concerned because his range rod seated deeper than normal.
I purchased a lapping tool. The Dpms match upper was square and true. I had torque the barrel nut to all I could muster using a cheater bar old school style. I will glue in at roughly 30 lbs as the new logic dictates.
I will go a step further though in set up. In the past. I had ar 15 that would shoot bug hole groups if feed one round a time in the chamber. Proving a good barrel and load. When feed from a magazine groups would open greatly. I suspected bullet runout caused by the feeding process.
I need to make up some dummies any way to speed up testing at the range. One I had the upper receiver lapped in with out installing the gas block or hand guard. I placed a dummy in a magazine drew a line with a marker to index it , released the bolt and let it slam home. I careful ejected the dummy into my hand . The deep dents in the shoulder were numerous, there was also some additional bullet run out.
Out came the dremel for some throating it took quite a bite to eliminate the dents to the shoulders. Those dents can not have a postive influence on headspace therefore accuracy. The drag can not have a positive impact on feeding and reliability . Bullet run out alway is detrimental to accuracy.
I will report back after testing. I dont know if the work will over come a possible out of spec bore. I cant find who the maker was.
I dont see how to post photos . I hope my description is clear and helpful
I purchased a lapping tool. The Dpms match upper was square and true. I had torque the barrel nut to all I could muster using a cheater bar old school style. I will glue in at roughly 30 lbs as the new logic dictates.
I will go a step further though in set up. In the past. I had ar 15 that would shoot bug hole groups if feed one round a time in the chamber. Proving a good barrel and load. When feed from a magazine groups would open greatly. I suspected bullet runout caused by the feeding process.
I need to make up some dummies any way to speed up testing at the range. One I had the upper receiver lapped in with out installing the gas block or hand guard. I placed a dummy in a magazine drew a line with a marker to index it , released the bolt and let it slam home. I careful ejected the dummy into my hand . The deep dents in the shoulder were numerous, there was also some additional bullet run out.
Out came the dremel for some throating it took quite a bite to eliminate the dents to the shoulders. Those dents can not have a postive influence on headspace therefore accuracy. The drag can not have a positive impact on feeding and reliability . Bullet run out alway is detrimental to accuracy.
I will report back after testing. I dont know if the work will over come a possible out of spec bore. I cant find who the maker was.
I dont see how to post photos . I hope my description is clear and helpful