Originally Posted By: dan158How should they slide into the receiver?? Should they be snug or loose fit? And if loose fit does that affect accuracy?? Thanks.. Dan
it should be relatively snug.
all the upper/barrel combo's i have are pretty tight, but dont need any special handling to insert the barrel extension into the receiver.
as you guessed, you dont want it floppy in there - it should be snug. the barrel nut will force the receiver extension to mate up with the receiver, but you still wouldnt want any extra play than necessary to insert it.
an interference fit (the heat/cold trick) is probably a bit too snug, but close enough that it shouldnt hurt anything.
hth