LL - Roger all. Thanks for "getting right on it". The LaRue is about as solid as anything I've seen short of an AR-10/SR-25 or SPR with a full length top rail. We've got several members with current professional experience that will be along later. They've faced the same problems you've got and can give you the run-down on what/why and will either reply here or in a PM. Meantime, do a search, we've discussed the problem before. Try:
http://www.professionalsoldiers.com/...ghlight=McCann
Peregrino