Receiver Mandrels - Trues action to bolt raceway rather than threads, which may not be aligned to action. Two sizes (.701" and .703") to fit actions with nominal .700" diameter raceways. Spare .703" mandrels available separately. Instructions included. Mfg: La Bounty SPECS: Receiver Mandrels - Steel, hardened to Rc 45, in-the-white, 10" (25.4cm) long. .701" (17.80mm) and .703" (17.86mm) diameter. Fits nominal .700" diameter bolt action receivers.