Are M-15A4 uppers compatible with AR-15 lowers?

The short answer is no, they are not. There really is no such thing as an M15A4.

The classic M15 is a squad automatic weapon variant of the M14 rifle. The catch here is that neither the M14 or the M15 has a split receiver, it’s a single piece. 

So in other words, it’s not compatible at all with an AR-15.

If you’re looking for compatibility, the closest you may get is the following list of Ar-15 and/or Ar-10 parts:

  • Buttstock assemblies
  • Triggers and trigger springs
  • Bolt catch roll pin (Armalite Style only)
  • Hammers and hammer springs
  • Pistol grips (a spacer may be needed for certain models)
  • Receiver extension (Buffer Tube)
  • Disconnector and disconnector spring
  • Buffer detent
  • Magazine release buttons and springs
  • Safety selectors

Leave a Reply

Your email address will not be published. Required fields are marked *