What is the estimated service life of these in a CAR AR? I have an old SGW that the tube looks as if it never had the little lip on the end of it it is so worn.

Will this contribute to ftf or ftEj issues at some point or does the CAR gas system send a strong enough pulse through to make this a non issue?

I didn't notice this before as it was my first AR. Since then I built an M4gery on a MEGA lower and when putting it together noticed the difference with the tubes.

One other thing I noticed was that the tube seems to have worn the inside of the carrier key to one side more than the other. I should replace both and will but I still wonder about the estimated service life of the tube in case it is one of those parts that are good to have an extra sitting around.

Thanks guys I appreciate any input.