I'm not going to try to predict how various ammos will chamber or extract. The usual test would be you don't want the stripped bolt to close on a field but it's OK to close on no go. Surplus military and loaded commercial ammo vary too much to try to achieve a benchrest chamber unless you're strictly shooting your own matched loads. Everything that experiences friction wears a little, but it's heat that accelerates the rate of erosion. So the throat-leade of the barrel will wear out long before anything behind it. As we're seeing, some folks seem to be getting some gas cutting up at the piston, but it may be a maintenance issue.

 

From what I have gleaned around here the bolts are the weak link. Some people even change them out with USGI or aftermarket versions. Clint McKee's book "The M14 Complete Assembly Guide" talks about this subject on pages 75-85 and he shows how to do a refitting with pictures.
Most of what I hear the receivers are as good as any. Fitting a USGI bolt may require grinding the receiver and McKee warns about possibly ruining the receiver.
I have no first hand knowlegde of these, this is just passed on info.
Edit: I thought qustion was about Chinese receivers and my answer pertaines to them.

 

if your dealing with good quality american made components, your headspace should not measurably change during the life of a barrel. if you can see the headspace change using only a go, and no-go guage, you have big problems.

 

I checked the headspace with the 7,62nato field gauge first and it passed then i read on the under side of the barrel it says 308cal in fine print. Being its a norinco sporter i'm thinkiing now its in 308win so i took out my 308win field headspace gauge and it passed on that one too. The bolt won't close on either field gauge. Of course now it has my curosity on wether it will pass on the 308win go and no-go gauges now too. I want to see exactly were the headspace is at this time before i start shooting it. Since i hear and read alot about the m1a's and m14's having headspace problems its making me over zealous about keeping an eye on the headspace and probably going to check it more often than it needs to be checked. Maybe i'm over reacting to this??? Does the headspace change that often?

I just want to learn about this wether its a problem or not and put it to bed and move on. But all this talk about bad chambers/barrels with headspace problems has me worried. Thanks, bill