The CMMG AR-15 Bolt Catch Kit (CMMG part no. 55AFF34) packages the bolt catch with the small parts that go with it, so you can replace or rebuild the catch in one purchase. The kit is made for AR-15 lower receivers and for CMMG Mk4, MkGs, MkG, Mk17 and Mk57 lowers. It includes the bolt catch itself, the plunger and spring that go with it, and the roll pin. That makes it a convenient parts-bin fix when a catch is worn or a small part has gone missing during a build.

Key Specifications

• The kit fits AR-15 lower receivers, covering the common AR-15 pattern lower.
• It also fits CMMG Mk4, MkGs, MkG, Mk17 and Mk57 lower receivers, the CMMG platforms CMMG lists for it.
• The kit includes the bolt catch, the part that holds the bolt open after the last round.
• It includes the bolt catch plunger, part of the catch assembly that goes in the lower.
• It includes the bolt catch spring, which pairs with the plunger.
• It includes the bolt catch roll pin, so the retaining hardware comes in the same kit.

Frequently Asked Questions

What comes in the CMMG bolt catch kit? The kit includes the bolt catch, bolt catch plunger, bolt catch spring and bolt catch roll pin.

Which lowers does it fit? CMMG lists it for AR-15 lowers and for CMMG Mk4, MkGs, MkG, Mk17 and Mk57 lower receivers.

Is this the same as the CMMG bolt catch by itself? No. This is the complete kit with the plunger, spring and roll pin as well as the bolt catch.

Buy the CMMG AR-15 Bolt Catch Kit

When a bolt catch wears out or a small part disappears, you want the whole set on hand rather than a single piece. This kit covers it. Browse more AR bolt catch and release parts and order from our Lubbock, Texas gun shop for fast, direct shipping.