Are you talking about a TCR (Thompson Center Rifle)? They made it originally as the TCR-83. It had a set trigger, and a forearm that had a lever that flipped down and released the forearm. Then open the action and the barrel comes off. Easy to change barrels. Barrels ranged from 22 hornet, to 7MM Mag. Then they changed it in the late 80s to a single trigger, and I think they called that model the TCR-Hunter. Then in the early 90s they brought back the set trigger and called it the Aristocrate. At that time they also added the Magnum Conversion. You had to send your reciever back for the conversion. Then they also came out with the run of magnum caliber barrels. I own a TCR-83, with .22-250, .243, 7MM Mag, 30-06, .35 Whelen, .338 Win Mag, and a 12Ga with 3 1/2" chamber with removable chokes. I have been carrying this gun in .338 for the last three years during hunting season. The only thing I don't like about the gun is that it is hammerless.