We have not had any function problems really with the bushmasters other than the following.
A2 match sights not tracking correctly in windage and in some rifles at the wrong time.
two stage triggers going south and not being able to fix them.
We have like 15 bushmasters in our club we issue to members who qualify and to use for our junior programs and clinics.
Out of the 15 rifles we have had to do sight work on 2 rifles and trigger work on 9 of them. all of these weapons have less than 1,500 rounds threw them and are well taken care of and some with less than 700 rounds threw them.
We were able to adjust 6 of the triggers and the other 3 lowers I took back to camp perry with me to the bushmaster rep. as they do great service work and he said he worked on them for hours eliminating what parts were defective. one was just the trigger, one was hammer and trigger and the other was the complete trigger assembly. It was explained to me they had a few issues but have since corrected that problem and the lowers I got back from them fixed the next day are working very well.
Would I buy from bushmaster again, yes I would.