Hello all,

I have just received an almost new Colt Hbar 1/7 20 inch upper. My receiver was an 80% and I used to have a DPMS 16 inch carbine upper on it. It fit great and tight. The Colt upper is a little odd?

The front pin hole is fine with a hairs worth of play if any. The rear hole in the Colt upper probably has .75 of a mm of play, sorry maybe I should have measured. It also has a little side to side play.

Like I said my DPMS 16 inch was great and tight. I assume I need to get one of those pin adapters for the rear of my lower/upper. What exactly am I looking for and where is the best palce to buy one? Any links would be great too!

I'm not opposed to drilling out the hole in the lower or upper either if I have too.

Also, who has a good price on a decent bolt carrier group?


Thanks!

Quoted:   Hello all, I have just received an almost new Colt Hbar 1/7 20 inch upper. My receiver was an 80% and I used to have a DPMS 16 inch carbine upper on it. It fit great and tight. The Colt upper is a little odd? The front pin hole is fine with a hairs worth of play if any. The rear hole in the Colt upper probably has .75 of a mm of play, sorry maybe I should have measured. It also has a little side to side play. Like I said my DPMS 16 inch was great and tight. I assume I need to get one of those pin adapters for the rear of my lower/upper. What exactly am I looking for and where is the best palce to buy one? Any links would be great too! I'm not opposed to drilling out the hole in the lower or upper either if I have too. Also, who has a good price on a decent bolt carrier group? Thanks!

Can you measure the holes with a caliper in English units?

Scottyryan,

I will tonight, I have been searching the parts vendors and found some different stuff.  Some of it is for large hole receivers and small hole uppers. Others are for the opposite way and now I see I need to find out what the exact sizes are.

Thanks for replying too!

I didn't measure it, but it seems my issue is side to side play and not up and down. I took another look at it tonight to see what was the actual issue.

From what I did find to day it looks like I just need to find a way to ease the rattling a little for my own benefit.  

I have the same problem with an LMT build.  LMT lower and upper.  I ordered an Accuwedge and I'm hoping this will tighten the two.  The 6.8 SPC rifle currently shoots 100% though.  Like you, the rattle bothers me.

ETA: I think the problem is with the rear lug of the upper not sitting snug with the lower shelf. I wish I had a caliper (left it at work) to measure the rear lug on the LMT upper and compare to a snug fitting upper on the same lower.