Best Glock 20 & 21 Accessories 2026: 10mm & .45 Upgrades

Buy in this order: magazines first, then a chest holster, then a light, then a match barrel, and only then optics and a trigger. The large-frame Glock is a backcountry tool before it is a range toy, so the spend that keeps it running and on your body in the field comes before the spend that makes it shoot marginally better.

Key insight: The Glock 20 and Glock 21 share the same frame, so the holster, light, sights, and trigger on this list fit both. Only the barrel and magazine are caliber-specific. If you run a MOS-cut G20, the optic-ready slide already accepts an RMR-footprint red dot through the plate system, so put that budget toward the optic and light rather than a slide swap.

The GunfightersINC Kenai chest holster (from $159) is the best woods-carry option for the Glock 20 and 21. A chest rig keeps the pistol clear of a pack hip-belt and accessible with a slung rifle, which is exactly where a hip holster fails on a hunt. The Kenai uses passive Kydex retention, so the draw is clean with no straps to unsnap, and the Kydex-and-nylon build sheds rain, snow, and brush. The light-bearing version (from $189) clears a TLR-1, so the holster and the light below work together. GunfightersINC molds Kenai fits for the Glock 20, 21, and long-slide 40; pick your generation and light configuration when you order, since the Gen5 10mm uses its own shell.

This is a chest rig, not a concealment holster. If you also want to carry the same large-frame Glock in town, pair the Kenai with a separate appendix or OWB setup; the picks in our best .45 ACP pistols guide cover concealment for the G21 in detail.

The Brownells BRN match-grade threaded barrel ($121.93) is the barrel to run if you shoot hard-cast 10mm. The factory polygonal barrel is not rated for hard-cast lead, which is the load most hunters and bear-defense carriers choose for deep penetration. The BRN uses conventional land-and-groove rifling that is rated for the non-jacketed cast bullets the factory barrel discourages, with a button-rifled 1-10 twist. The 9/16-24 muzzle threads accept a 10mm suppressor or compensator, and the 416R stainless with a Black Nitride finish stands up to backcountry weather. For the loads that earn the G20 its reputation, see our best 10mm ammo guide, which breaks down hard-cast and hunting loads in detail.

This SKU fits the Glock 20 Gen 3/4, not the Gen5 MOS, so confirm your generation before ordering; Gen5 owners need a Gen5-specific barrel. The threaded muzzle adds a suppressor option without an NFA tax under current law, but the barrel itself is not a regulated item. Note the 5.20-inch length extends past the slide and changes holster fit, and the threaded muzzle needs a thread protector or a device installed. This is the .45 ACP divergence point: the Glock 21 takes its own .45-caliber barrel, not this one.

The Trijicon RMR Type 2 ($558.99) is the most durable red dot for a MOS-cut Glock 20, and the Holosun 507COMP ($369.99) is the best value. The RMR earns the top slot on durability: Type 2 electronics eliminate recoil-induced flickering under the snappy 10mm impulse, battery life runs up to four years for set-and- forget carry, and the industry-standard RMR footprint drops onto the G20 Gen5 MOS plate system. The 507COMP trades some ruggedness for a much larger window that keeps both eyes engaged, plus a multi-reticle system that covers a precise dot and a circle-dot for close work, and a side battery tray that swaps the CR1632 without losing zero.

Both optics use the RMR footprint, which the G20 Gen5 MOS supports through its plate system. Run the right MOS plate for the footprint and pair either dot with the suppressor-height sights below for a co-witness. Drop either red dot into our pistol builder to see how it layers onto the Glock 20 alongside the rest of this list.

The Glock 20 in 10mm Auto is one of the most common semi-autos chosen for bear country because it pairs deep-penetrating hard-cast loads with high capacity. A 200-grain hard-cast bullet at 1,200-plus fps drives straight through heavy muscle and bone, and a 15-round magazine carries more total penetrating shots than a six-shot revolver, with faster follow-ups and quicker reloads. The Brownells BRN barrel above is rated for those non-jacketed hard-cast loads, which the factory polygonal barrel discourages.

A heavy-framed revolver is still the traditional answer, and for some carriers it is the right one. If you want to weigh the wheelgun, our best .44 Magnum revolver guide covers the revolver alternative for bear defense head-to-head. The .45 ACP Glock 21 throws a heavier bullet at lower velocity and energy, so it is a capable defensive pistol but not the hunting and bear-defense tool the 10mm G20 is.