In Catalog No. 17 they show these for Custom Shop barrel calibers...
.17 Mach IV, .17 Rem, .22 Hornet, .22 K Hornet, .222 Rem, .22 PPC, .223 Rem, .222 Rem Mag, .22-250, .220 Swift, 6MM PPC, 6MM TCU, .243 Win, .257 TCU, .257 Roberts, .25-06, 6.5 TCU, 6.5X55, .264 Win Mag, .270 Win, 7MM TCU, 7MM-08, .284 Win, 7MM Rem Mag, 7X57, 7.62X39, .280 Rem, 308 Win, .30-06, .300 Win Mag, .35 Whelen, .375 Win, .38/55 Win, .416 Rem Mag and .45-70. It looks like the standard barrel length was 24 inches but there was also a 20-inch option and a "bull barrel" option. My .22 CCM is a "bull barrel" with a muzzle dia of .75 but that only makes about an 8-pound rifle. It also says they would make other lengths and one time when I called they said that they could make a 26-inch barrel. Barrels could be in a matte or high luster finish and there was the option of Mag-na-Porting, and the .416 Barrels came with a T/C Muzzle Tamer.
Catalog No. 9 showed buttstocks and forends of select walnut and checkering on grips and forends not already having checkering. There was and option to refinish shiny finish barrels or receiver in matte finish or vise versa. The put a matte finish on my TCR-83 and also did the Magnum Conversion on it.
Wish the Thompson-Center Custom Shop was still around!!!