Precision machined from forged 7075 T6 aluminum, the CMMG Mk4 AR15 lower receiver is the quality mil-spec lower ready to be the foundation for your next build. The Mk4 stripped lower comes standard in your choice of seven Cerakote finishes and can be assembled using any mil-specLower Parts Kit. If you want to add some customization to your next AR build, consider upgrading to one of 10 different cerakote color options and pairing the Mk4 stripped lower with ourGunbuilder's Lower Parts Kit and picking out theTrigger Guard,Pistol Grip, andFire Control Group to make your project whatever you imagine.Don't forget to check out CMMG'sRifle Stock Kits andPistol Brace Kits to round off the parts for the AR15 Mk4 stripped lower.Lifetime Quality GuaranteeWe aim to please, that's why every CMMG product is backed by our Lifetime Quality Guarantee against material and workmanship defects.Learn More.