Rimfire action specs: mounts, screws, torque and barrels

Scope-mount interface, action screw torque and barrel attachment for popular rimfire actions. Every value comes from the maker's manual or spec page, or a named rail or chassis maker. Where nothing is published, we say so rather than guess.

Safety: follow your stock or chassis maker's torque spec. Factory values below apply to the factory stock; an aftermarket chassis may call for a different number. Over-tightening can damage parts.

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Action	Receiver base / dovetail	Stock footprint	Action screw thread	Action screw torque: factory stock	Action screw torque: chassis	Barrel attachment
Tikka T1x	11 mm dovetail machined into the receiver, which is also drilled and tapped. Rail hole pattern is T1x-specific: 2.508 in between the center holes, vs 3.245 in on the T3/T3x, so T3x rails don't fit.^[1]^[2]	Stock footprint is the same as the centerfire T3x (Sako).^[3]	Not published by Tikka	7 Nm (62 in-lb) with a metal trigger guard; max 5 Nm (44 in-lb) with a plastic guard. Fit the recoil block and push the action rearward first.^[4]	Not published – check your stock/chassis maker	Not published by Tikka. American Rifleman saw three set screws plus bedding compound (not threaded); Tikka's general series copy says "sturdy thread". Sources conflict.^[1]
CZ 457	Integral 11 mm dovetail; not drilled and tapped for bases. Use 11 mm rings or a clamp-on rail.^[5]^[6]	Not published by CZ (457-specific; check stock maker fitment)	Not published by CZ	3.5 Nm (about 31 in-lb) for the two stock screws (pos. 73 and 74).^[6]	Not published – check your stock/chassis maker	Clamp: the barrel slides into the receiver and is held by two barrel screws, 5.5 Nm (about 49 in-lb). Tighten the magazine-housing screw before the barrel screws.^[7]
Bergara B-14R	Drilled and tapped in the Remington 700 short-action rail pattern (3.627 in center spread). Bergara: 3 Nm (25 in-lb) for 6-48 and 8-40 base screws.^[8]^[9]	Bergara says most of its rifles are based on the Remington 700 footprint; it doesn't single out the B-14R stock inletting.^[9]	Not published by Bergara	6.2 Nm (55 in-lb); front screw first, then rear.^[9]	Not published – check your stock/chassis maker	Not published by Bergara (the manual shows no barrel-change procedure).^[10]
Ruger 10/22	Some receivers are drilled and tapped and ship with a scope base adapter: four screws, max 12–15 in-lb.^[11]	10/22 pattern (single takedown screw).^[11]	Not published by Ruger	Takedown screw: "hand tighten" with a 5/32 in Allen wrench; Ruger warns not to over-tighten. No number given.^[11]	Not published – check your stock/chassis maker	V-block: a barrel retainer V-block and two screws, hand tightened (no number given).^[11]
Zermatt RimX	Sold with a rail; 0, 20, 30 or 40 MOA options.^[12]	"True to scale Remington 700 footprint" (Zermatt).^[12]	Not published by Zermatt	Not applicable (sold as an action)	Not published – check your stock/chassis maker	Threaded tenon (Zermatt publishes tenon prints for barrel makers).^[12]