View Full Version : Colt ar15 upper fit on off list lower?

01-28-2010, 2:40 PM
Hey i was wondering if the Colt uppers fit on a off list lower? ive heard that they have different takedown pins.. is this true?



01-28-2010, 2:46 PM
Yes, just make sure you order the right size holes for your upper. Some older ones wont fit.

01-28-2010, 2:54 PM
Yes they will fit. Some of the older ones as stated have an oversized front pivot hole so you can buy an adapter for a few bucks.

01-28-2010, 3:00 PM
thanks! do u know were you can find a adapter?

Barney Gumble
01-28-2010, 3:06 PM
^^^ Correct it is the pivot pin not the takedown pin.

Milspec is .250". For a little while in the early '90s Colt civilian rifles were produced with a larger takedown pin. Unless you have an upper from that period it's unlikely you have a big hole upper.

As others have said, if it turns out you do, just have to get the adapter for the standard-size pin.

More info: Go to the link below and scroll down to "Small hole vs. big hole".


Barney Gumble
01-28-2010, 3:08 PM
thanks! do u know were you can find a adapter?

1. Go to google
2. click on "shopping"
3. type in "colt pivot pin adapter"