Does AR gas tube ever wear out?

[Bushmaster-M4A3]

I'm about to rebarrel a carbine upper and I'm wondering if I could reuse the gas tube, or should get a brand new one while I'm at it?

[Robb Jensen]

I replace them every 5-10K rounds. When ever I sear the end of if wear down so that it's the same size as the rest of the tube. A new one has a bulb like end which is larger than the tube itself.

[99HMC4]

The gas key wears too....

[skyugo]

any erosion inside the tube? or just the frictional wear from the gas key really?

[Robb Jensen]

The gas key wears too....

I've had quality chrome lined keys go beyond 40K rounds. That was with a Colt carrier key over a few year period. I have no doubt a BCM key would do it too.

[MadcapMagician]

A good idea for re-barreling is to replace the gas tube and bolt as well.

[Robb Jensen]

A good idea for re-barreling is to replace the gas tube and bolt as well.

Not a bad idea but there's a very easy way to check it:
If a new gas tube or the gas tube alignment gauge fits snugly into the carrier key then your carrier key is GTG.