CMMG AR-15 Lower Parts Kit — No Grip/Fire Control Group (55CA601)

Description

Building an AR-15 lower usually means buying a full parts kit and then throwing half of it in a drawer once you drop in a nicer trigger or a grip you actually like. CMMG built this Gunbuilder's kit to fix that. It hands you all the small mil-spec guts for a stripped lower, then leaves out the pistol grip and fire control group so your money goes toward the upgrades you already have in mind.

Inside you get the takedown pin, pivot pin, and their detents and springs, the bolt catch with its plunger, spring and roll pin, the magazine catch with button and spring, the safety selector and detent, the buffer retainer and spring, plus the trigger and hammer pins. What's left out is intentional: no trigger, hammer, disconnector or their springs, no trigger guard, and no grip. That covers everything commonly swapped for aftermarket parts, which is exactly the point.

Where the CMMG Gunbuilder's Kit Earns Its Keep

This kit shines for anyone running a match trigger, a drop-in cassette, or an ergonomic grip that isn't the old A2. Builders who've run it alongside other brands tend to rank the CMMG machining and finish near the top, and plenty keep a spare on the shelf for future builds and repairs. The parts are labeled and organized in the package, which makes a real difference if this is your first lower.

Fitment and Compatibility for the CMMG AR-15 Lower Parts Kit

Everything here meets or exceeds mil-spec and drops into standard AR-15 lower receivers. Because the fire control group and grip are missing, plan to source those separately along with a trigger guard and roll pin if your build needs one. Pair it with your favorite trigger and grip and you've got a clean, no-waste path to a finished lower.