Can someone please explain this to me. It seems with the lip on the barrel against the upper, and the nipple in its slot there is really no “adjustment” to make. I have seen the go and no go gauges, but how do you adjust it if neccessary?
Essentially, you don’t adjust it. It’s set when the barrel extension is installed and the chamber cut by the manufacturer.
To an extent you can play around with many different bolts to adjust it up/down a thousandth or two, but if you assume bolt QC is held tightly, there’s not much to be gained there.
The best you can do is measure what you’ve got and determine whether or not to rebarrel. This is an action that’s probably more appropriate on a used carbine that has had several thousand rounds down the ube rather than on a a new barrel. The idea is to see if locking lug wear is occurring and HS is increasing from the brand new dimension. But still, you don’t need to start thinking about it until you are into the NO GO/FIELD realm.
I wouldn’t sweat it, this is one area where just about everyone has things sorted out pretty well.
If the chamber is unchromed and short (sub GO) then you can use a chamber reamer to deepen the headspace but if it’s too long then the fix is much more complicated. If it’s short and chromed then swapping bolts is the only reasonable remedy but there isn’t a lot of latitude between bolts.
Ok, thanks guys. Eases my mind.