Magpul SGA Stock (Mossberg 500/590/590A1)

The Magpul SGA Stock for the Mossberg 500/590 family (model MAG490) is the most popular aftermarket stock for these platforms because it solves the two biggest factory problems at once: fixed length-of-pull and a comb height that doesn't co-witness with a red dot. The stock ships with multiple 0.5-inch spacers that adjust LOP from approximately 12.5 to 14.5 inches, letting shooters tune fit for body armor, heavy clothing, or different shooters in a household. The included comb risers raise cheek weld geometry to align the eye with mounted optics on the receiver rail, which the factory plastic stock cannot do.

Installation is true drop-in: remove the factory stock bolt, slip the SGA on, torque the bolt back down, and the gun is ready. No fitting, no gunsmithing. The stock is compatible with the Mossberg 500, 500 ATI, 590, 590A1, 590S Tactical, and Maverick 88 (any 12 or 20 gauge variant using the standard Mossberg stock interface). It is NOT compatible with the Mossberg Shockwave (no stock) or the 590 Shockwave variants without a stock interface.

Sling attachment is the other strong point. The SGA includes ambidextrous QD sling cup positions plus traditional sling loops front and rear, so any sling system the user already runs (single-point, two-point, QD adapters) works without an additional purchase. Reinforced polymer construction holds up to standard 12-gauge recoil indefinitely; the angled rubber buttpad cuts felt recoil noticeably compared to the hard polymer factory pad.

For shooters running an optic on the 590A1's factory top rail, the SGA's adjustable comb is functionally mandatory. The factory stock's fixed comb forces a chin weld with most red dots, which destroys consistency. The SGA fixes that for under $120.