Check the inside of the gas key as well.
Ive had a few that had tool marks,more accurately described as ridges,on the key internal surafces.Easily seen with white light and can be felt easily on a new tube prior to assembly.I had one BCG I missed this on and the gas tube bulb was effectively filed down rather quickly.
Have also had one that the bore of the gas key was not fully drilled to same I.D. and got tight in the rear of the gas key on the gas tube.This also caused premature/deformation wear on gas tube bulb.
One thing I really like about the hated MIM gas keys that LMT uses is the bores are smooth as glass and very consistent I.D..Personally think these keys will wear the gas tube less than the hard chrome standard models....but speculation on my part.

