Backcountry Xtreme Actions, specifically designed for cartridges 3.985″ length with a .585″ rim diameter such as the .416 Rigby, the 338 Lapua Magnum or the 378 Weatherby based cartridges. The TAC338 is also larger than the standard TAC action. It is 0.050 larger in diameter at 1.400″and 0.465 longer. That is needed to accommodate the 0.750 diameter bolt that is necessary for these cartridges. 3.985″ length is used with a 338 Lapua magnum bolt face, and uses a modified M16 type extractor; Wyatt center feed box, and follower. TAC338 actions are designed for tactical, long range hunting and competition shooting platforms. The TAC338 actions use a straight bolt handle. All tactical actions feature a screw-on bolt knob. The bolts have a new proprietary coating that makes them as smooth as glass. They are bead blasted 416R stainless steel. The .300″ recoil lugs, combined with stiller quality standards leave little to be desired when building your dream rifle. Receiver can be ordered with an added dual pinned rail with #8×40 screws for scope base mounting, 20 MOA Picatinny Rail – *or add the optional 40 MOA Picatinny Rail, both available in our products tab for purchase.