Replaced the iron sights with a 4x30 scope, got everything tuned in for final adjustments at the range. Ok everythings working fine grouping are decent I'm happy. That's on trip #1. Gun is cleaned put away ready for the next trip. Trip # 2 the next week starts out great grouping are good. Then I start getting wild shots all over the target, so I check that everything is tight and hasn't moved, all good so adjust to bring it back on target, everything is good. Again the wild shots start. One of the RO's mentioned that the top rail being "plastic" or composite might be flexing causing the inconsistency in the shots and I might want to change it to aluminum and eliminate the problem. My question is, is this a possibility and can the top rail be replaced with a aluminium rail.