First introduced at the 2025 edition of SHOT Show, the Mossberg 590R and 590RM pump-action tactical shotguns get refreshed for 2026 with a new stock interface that makes them even more versatile.

On both models, the original M4-style extendable stock has been ditched in favor of a 8-position extendable stock with an interchangeable pad, installed on a side-folding buffer tube provided by Chisel Machining that allows the stock to be folded to one side to make the shotgun easier to store, transport, or maneuver in confined spaces. The Chisel Machining stock is installed on a vertical Picatinny rail, meaning it can be easily removed and replaced with any Picatinny-compatible stock at the shooter's will.

The Mossberg 590R Chisel pump-action shotgun is chambered for 12-gauge, 76mm / 3" shotshells and features a 6-shots magazine tube, enlarged and beveled loading port with exposed follower, a 18.½-inch barrel with integrated heat shield, and a set of folding MagPul MBUS-3 sights; the 590RM Chisel model feeds through detachable 10-shot magazines, features an 11.½-inch barrel with bead front sight, and an M-LOK handguard.

Both models are built on a Cerakote polymer-ceramic finished aluminum alloy receiver for superior abrasion and wear resistance and added anti-corrosion protection, and feature a rotary AR-15 style safety switch.

MSRP for the US market is set at $1,330.00 for the 590R Chisel shotgun and $1,435.00 for the 590RM Chisel shotgun. The 590RM Chisel shotgun is an NFA item, and all NFA rules apply.