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Posted: 12/24/2003 1:00:24 PM EDT
CMT lower, Model 1 upper, Colt ar15 guts.
Problem: First trip to range with new build. One 20 rd mag fired OK. 2nd mag, about 4th shot, it doubles. 10th shot doubles again. At this point I'am like W O W.
So, let me find out whats going on here. Pull trigger and hold it back, fires one round. OK so for, didn't double on me. I let go the trigger and it fired a 2nd shot. Now I start to hold it each time I fire and I get a 2nd shot two or three times out of six pulls. I don't really want to live with Bubbu for the next ten years, so can anyone HELP with this little problem?????????????????????
I broke it down and checked all the parts and cleaned it at the range and it still doubled.

H E L P!!!!!!
Link Posted: 12/24/2003 1:17:46 PM EDT
Your hammer and disconnector timing is out of wack.  Easiest thing to try is a new disconnector.  There are instructions here for adjusting the timont on the disconnector, but I am not really qualified to tell you how to do it (the blind leading the blind?)

If you have another set of fire control parts around, try them.  This is a problem that should have been caught doing function checks with the upper off the gun.  These checks are detailed in the USMC M16 manual (about 5 bucks, and a must have for AR owners).

Someone will be along in a short to direct you to the thread on timing your disconnector.

Merry Christmas....
Link Posted: 12/24/2003 7:57:47 PM EDT
Sounds like your diconnect is not catching.

To check if it is functioning properly, uloand the weapon, cock it, then pull the trigger and keep it pressed down. Then charge it again while trigger is still depressed and then let off the trigger. It should make a loud "click" if the hammer is catching on the disco.
Link Posted: 12/24/2003 9:55:06 PM EDT
FAQ II

Hoppy
Link Posted: 12/25/2003 5:44:52 AM EDT
I think Hoppy means [url=http://ar15.com/forums/announcement.html?b=3&f=66&id=187]FAQ III[/url]
Link Posted: 12/25/2003 2:46:10 PM EDT
He did and I found it. Thanks to all who answered. This is what I did and what I found:
Took my lower and pulled the hammer and set it to fire. Pulled the trigger and held it back,
reset hammer and released trigger with a quick release and connector locked hammer in ready
position for next shot, did this 106 times without a double fire indication. Then I did the same thing, but I now released the trigger slowly. 10 out of 10 times as I released the trigger the hammer released and I would have had a double. Did not see any movement of trigger other than normal. Do I need a new connector or do you still think a little off the bottom will help. Or maybe try the file and then new if needed?

Comments --- suggestions  welcomed
Link Posted: 12/25/2003 6:22:39 PM EDT
When lowering the hammer with the trigger at rest, you should have a gap between the hammer/disconnector hooks of about one sheet of letter paper.  If you have more than this, then as you release the trigger, the disconnector releases the hammer before the trigger sear is in position to catch the hammer.

Since it's easy to re-time the disconnector by just removing metal from the front contact edge where the disconnector rides on top of the front of the hammer, you may as well just re-time it and get it over.

Also, to make checking the disconnector/hammer engagement simple, just install the hammer spring with the legs below the trigger pin.  This will allow you to push the trigger pin over to pull the disconnector, and file/ fit in only a few steps.  Once you have the correct gap between the two (almost touching as the hammer passes the disconnector), and then reinstall the hammer spring legs in correctly.
Link Posted: 12/25/2003 6:28:51 PM EDT
Originally Posted By ybh_613:
CMT lower,  "Colt" AR-15 guts.
View Quote


Your using Colt small pin FCG parts, and not the standard Colt large pin FCG in a small hole receiver.

Pull the hammer/trigger and check the pins against the parts.  The pin should fit with only a little slip, and not like a BB in a boxcar.

If you are using colt large pin/hole parts in the CMT small pinholes, you have found your problem, and the FCG needs to be replaced (don't try to adjust a disconnector to fix the wrong parts used).
Link Posted: 12/25/2003 7:17:15 PM EDT
Originally Posted By Tweak:
I think Hoppy means [url=http://ar15.com/forums/announcement.html?b=3&f=66&id=187]FAQ III[/url]
View Quote


I stand corrected.  It is indeed FAQ III.

Thanks.

Hoppy
Link Posted: 12/26/2003 6:42:18 PM EDT
Small holes in CMT lower and small Colt pins.
My 1st ar15 is a Colt slab side preban I bought
in about 1968 or so. I bought a full set fcg as spares but did not use any of them as I have only shot around 300 rounds out of my prebie. Will fill Sunday afternoon and report results back to group.
Thanks to all.........
Link Posted: 12/29/2003 11:22:54 PM EDT
I filed the bottom front of the connector and it begain to release the hammer worse.
It got to the point that it was almost like a MG.
I installed a new hammer and the connector would not release the hammer after I released the trigger. I had to use a small punch to trip the connector. It locked the hammer  solid.
This is the same connertor that would not hold the old hammer. So, I replaced the hammer and connector and the gun works fine. I think the hammer somehow went/was  bad.
Thanks to all.
Link Posted: 1/1/2004 8:21:11 PM EDT
Last word!!!! Hammer was OK. Put old hammer back in and new connector and all works great.
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