Mech Tech Systems CCU Basic Carbine Conversion, .45 ACP, 16-inch Threaded Barrel, Glock 21 SF Compatible
This Mech Tech Systems Carbine Conversion Unit (CCU) turns a Glock 21 SF Gen 3 lower into a full-size, 16-inch barreled carbine that feeds from standard Glock double-stack .45 ACP magazines. Its quick-swap, tool-free upper installs in under a minute and preserves the familiar Safe-Action trigger feel. The matte-black tubular steel receiver, stainless button-rifled barrel, and 3-port muzzle brake add practical durability and recoil control in a lightweight package.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Specific Condition Notes: The exterior displays a few shallow scratches and minor blemishes from normal range handling. The bore is clean and shiny throughout.
Bore Condition: Good - Clean, well-maintained, minor wear marks.
Bore Rifling: Good Rifling - Intact, well-defined lands and grooves.
What’s Included
- Owner's manual
- One Glock OEM 13-round magazine
- Two aftermarket 27-round magazines
The straight-blow-back action uses a massive telescoping bolt housed in the tubular upper, contributing to reliable cycling with standard .45 ACP loads. The 16-inch stainless barrel provides an 80–150 fps velocity gain over pistol length barrels, and its threaded muzzle with a 3-port brake is ready for suppressors or other devices.
A right-side knurled charging handle and matching ejection port keep spent cases clear of right-handed shooters while allowing rapid manipulations. The ribbed polymer fore-end offers a solid grip and integrates rail mounting points for lights, lasers, or vertical grips.
The black polymer lower and collapsible M4-style stock give a 6-position length of pull adjustment, settling at 15 inches when fully extended. Compatibility with Glock 21-pattern magazines from 9 to 30 rounds ensures plentiful and widely available feeding options.
Because the upper is not serialized, it can ship directly to consumers in most jurisdictions, simplifying acquisition for shooters seeking a pistol-caliber carbine that keeps the Glock manual of arms intact.