You're welcome. There were three different versions of it a Mark V TRR, Mark V Magnum TRR, and a Vanguard TRR. I Mark V came in .223 Remington and .308 Winchester while the Mark V Magnum TRRs came in .300 Weatherby Magnum, .30-378 Weatherby Magnum, and .338-378 Weatherby Magnum. The Vanguard TRR came in .223 Remington and .308 Winchester. I'm not sure what order they came out in and as best as I can remember now these are the calibers that were available but there may have been one or two other calibers available.