CMMG Matte Black MK4 Receiver Extension Castle Nut

Gun Parts Cmmg UPC 815835017426

$8.79

at Palmetto State Armory

Price last checked Aug 17, 2026

Shipping calculated in cart

10 retailers · $17.99 to $20.60 shipped

Firearm Data Lab may earn a commission when you buy through this retailer link. Commissions never change a price or move a cheaper listing below a pricier one. When two retailers tie exactly, the one that pays us a commission is listed first.

Offers

Shipping estimate for one item to the lower 48 from the retailer's published policy or feed; the retailer's cart is final.

Price history

Lowest price across retailers each day.

Lowest seen: $8.46
Typical price: $8.75
Tracked since: Apr 10, 2026

Today's best price is $0.33 above the 212-day low and about typical.

Offers

Price history

Price alert