Quick Helpful Answers

The Modular End Cap System will fit any AR Style Lower Receiver as long as it follows Mil-Spec dimensioning & tolerancing.

No, the Modular End Cap System is designed to only work with compact action style systems be it drop-in uppers or drop-in kits that do not extend into the threaded section of the lower receiver. Examples are 22LR Dedicated & Conversion kits, or compact upper receivers like the BRN-180 & BRN-180S.

Our QD End Plate is made of 8620 steel so if you trust aluminum you will have no problem trusting our stronger version.

As long as the brace/stock is designed to fit a standard picatinny pattern mount then you will have no problem attaching to our Vertical Picatinny End Cap.