Thinking of buying another upper. Is it OK to switch the bolt and charging handle between the two?

I have read of headspace problems after awhile.

Technically this is a bad idea. The bolt wears to match the locking lugs of the barrel extension. Switching the same bolt back and forth between the two is a bad thing as it will excellerate wear.

You can however switch bolt carriers and charging handles - a new bolt will run you $50 for your rifle.

If you do swap I would get the gun head spaced before you shoot it again.

Yes don't switch back and forth. Installing is fine. Any product meeting Military Specs will be headspaced.

BrassEaster
Now just tell my how you are going to headspace it. Do you even understand the process involved?

To headspace the rifle you would have to take it to a custom gun smith who can remove the barrel extension from the barrel set it back and re-index it so the site tower is top dead center. Any just why would you do this since every bolt is made to military specs and virtually every barrel comes from the factory with the barrel ext. already indexed and installed and headspaced to accept the military spec. bolt

I think he means to check headspace between bolt swaps.

But why risk a kaboom when for $50 you can get a dedicated bolt?

Remember the bolt shortage of 1999? I've still got some put away for the next

The "gage, headspace, field" sells for between $10 and $30 still sealed in the USGI aluminum/mylar bag with gage card sealed inside.

Takes longer to type this than confirm the headspace is OK.

Swapping bolts WILL result in more wear on the bolt, but wear to the point of failing the gage check will take a long time.

-- Chuck

Just takes a second (or two) to check.

Sorry DH  Have it CHECKED for headspace.

I never really looked into this headspace stuff. Am I correct in thinking that if there is a headspace problem, the cartridge case has more room to expand and thus rupture and cause a major blowup.

A headspace problem will NOT cause a major blowup in the AR-15.  I have personally tested this and you will end up having an immediate case seperation in the middle of the case, but nothing comes apart in the gun.  If you have not personally tested this, don't spout your mouth here.  I am tired of hearing second hand BS on the subject.