The RX Helix form Merkel of Germany has a universal action length that covers calibers from .222 Rem to .300 Win Mag. Changing calibers (or chamberings) takes less than a minute with the appropriate barrel, bolt-head and magazine. Weaver rails are integrated into the action, and iron sights with three-dot rear and one-dot front fiber-optic inserts are standard. It is also a straight pull bolt and is very popular in parts of Europe.See video HERE