Colt AR15/M4 Mil-Spec Lower Parts Kit

(32 reviews)
Current Stock:

Factory Colt lower parts for AR15/M4 type rifles.


  • 1. Grip
  • 2. Grip Screw Washer
  • 3. Grip Screw
  • 4. Bolt Catch
  • 5. Bolt Catch Plunger
  • 6. Bolt Catch Spring
  • 7. Bolt Catch Roll Pin
  • 8. Mag Release
  • 9. Mag Release Button
  • 10. Mag Release Spring
  • 11. Buffer Retainer Spring
  • 12. Safety
  • 13. Buffer Retainer
  • 14. Safety Detent Spring
  • 15. Safety Detent
  • 16. Trigger Guard
  • 17. Trigger Guard Roll Pin
  • 18. Takedown Detent Springs
  • 19. Takedown Detents
  • 20. Takedown Pins


  • 5

    Posted by Clarke Thrower on 17th Nov 2022

    Fast shipping! Great product!!

  • 5
    Colt lower parts kit

    Posted by KM88 on 29th Sep 2022

    Very satisfied with this company prompt processing/shipping times product came as described genuine colt parts will continue to do business highly recommend

  • 5
    High quality Colt kit

    Posted by Unknown on 10th Sep 2022

    I’m an admitted LPK snob but these Colt kits are fantastic. It includes a chalky A2 grip but they have moved away from the hotdog selector and the colt catch is now black instead of grey park.

  • 5
    Colt AR15/M4 Mil-Spec Lower Parts Kit

    Posted by Brent on 29th Aug 2022

    Item was exactly as described at a good price. Shipping was fast!

  • 5
    Colt Parts & Products

    Posted by We The People Tactical on 30th Jul 2022

    AU has always been a great company to purchase from. As a dealer, not retail client, AU has always taken good care of us and has been a backup when my distributors have ZERO of what I need. I have been purchasing from AU a long time and I will continue to use them as a main backup for our shop.

  • 5
    Colt is great

    Posted by Happy Customer on 30th Jul 2022

    Waited to find a genuine Colt LPK since most of the others I have tried have been junk. Goes together tight and looks great. I will probably 20 lowers and Colt is the best.

  • 5
    Outstanding Company

    Posted by Matthew Bromwell on 29th Jul 2022

    Parts as described. Each transaction has been excellent.

  • 5
    As Advertised

    Posted by Unknown on 4th Jan 2022

    GTG, no issues. Just be aware this is a "spares" (partial) LPK. So, no fire-control group.

  • 5
    Colt AR15/M4 Mil-Spec Lower Parts Kit

    Posted by Marty on 22nd Sep 2018

    I was working on completing an Mk12 Mod 1 (M16A1 profile) lower receiver and needed the Colt LPK to complete the assembly. This is a genuine Colt LPK that includes every piece required to complete the assembly. AU has the best price, fastest shipping and no tax. They are hard to beat and that's is why I turn to them for Colt products. I am a repeat customer and have purchased complete Colt rifles, lower receivers, bolts, weapons lights, optics and accessories.