The life of a barrel is significantly reduced by not having a chrome-lined barrel. I've heard estimates range from half to 2/3 the life a CHF/CL barrel.

The twist rate is 1:8 on the newer Tantals. That twist rate is close enough to the original twist rate, which is 1:7.68.

A CHF/CL barrel has the life of about 30k. I've seen estimates in the 10k-15k for non-chrome, depending on how many rounds you put through it in a relatively short amount of time. These newer barrels don't keyhole, but they almost swallow the 7n6 bullets in a bullet test. I doubt there's much life in those Tantal barrels.

I recently picked up a CAI tantal, 10/11 production date with the 1:8 Barrel and I have just finished putting 1200 rounds through it and it has never once keyholed with 60gr Monarch or Tuammo. It doesnt 'swallow' the bullet, but at first glance it looks like it does because the way its crowned the rifling is cut back some the bullet goes in pretty far. But if you push it and rock it around you can see the rifling hits the bullet about 1/8" from the case. I used Century's e-mail tech support and they got back to me the next day with the year made and barrel twist rate.

I do not doubt there are some CAI Tantals out there with bad barrels, but I also think there are many with decent barrels. As far as barrel life I have a non chrome AR-15 barrel with 30,000 or more rounds through it (it was a low end DPMS range gun that was well used), the barrel was melonite or whatever it was coated I think but there is almost no rifling left and it will swallow a 5.56 round to the case. But that thing shoots pretty well, my 12 year old can put 30 rounds in 4" at 50 yards with a cheap 4moa red dot. It will keyhole once in a while and all those keyholes are in the same group, not going to win any accuracy or beauty contests with it but its still a good blaster/training gun.

That being said if you can get one with a chrome US or original barrel even for a couple hundred more I would get one. If you already have a decent shooting Tantal with a non-chrome barrel shoot it until accuracy goes to crap or it it has major keyhole problems and replace the barrel. Myself I like the Tantal, the CAI I have has been flawless and is fun to shoot, but any 74 would be the same to me, mine has all non-matching numbers and the bolt was well used, gas tube pretty rusted inside before they reparked it but everything else looks great. I bought the Tantal not knowing about the problems they had, I just ASSumed it had a chrome barrel. Honestly I've had my fun with it now and most likely it wont see 500 rounds a year from now on so I'm not worried about wearing it out. Even if I do someone will probably pay nearly what I paid for it a few years down the road with a shot out barrel.

I was going to sell the CAI Tantal off because I was worried about it at first, but then I figured if I sold it I would not not be able to find one with a chrome barrel and if I did it would have other issues. Sometimes its best not to fix what isnt broke.