 All but the XP-100R model were single-shot designs, while the XP-100R had a small internal magazine (holding four rounds), similar to most bolt-action rifles.The R model - for "repeater" - was made 1991-1997 in .223 Rem., .250 Savage, 7mm-08 Rem., .308 Win., .35 Rem., and 350 Rem.Mag.