I received my LMT lower half today, and I noticed that the receiver extension nut seems to be staked in place (pictures to come later if needed). Sections of the receiver plate are jammed in the little notches of the nut, somewhat like how LMT secures their carrier keys.

My initial impression (and I am rather new to AR's), is that this seems rather shortsighted. What if the user wants to change the buttstock system? It's no big deal for me, since I really like LMT's SOPMOD stock. However, how am I supposed to change out the plate for a sling loop? I know I can probably just use a punch and hammer to free the nut, but still, if I wanted a lower half that I had to modify, I could have just gotten an MT6400C lower.

(Of course, I can understand if LMT meant for their products to go straight into the field and wanted to take preventive measures.)

Colt does this as well. Its to keep the nut in place.

They are staked in place because they are properly installed.

Thanks for clearing that up. I didn't realize it was normal practice.

As stated, it's the proper way to install it.  It'll still come off easily enough with the proper wrench ($5) if you need it to.

If you install a sling plate, torque the nut to spec (or "snug"), then re-stake with a hammer and punch. It keeps the nut from turning, and is better than locktight since there's no messy threads when you remove, and it actually may be easier to remove than locktight.

rvb