I can move to safe with the hammer uncocked. Why? - Resolved

AR/M4 AR Technical Discussion
1

I just pulled out a rifle from the safe that I haven’t fired in a long time; a simple bone-stock Colt 6920. I was dry firing it and noticed that I could move it into safe with the hammer uncocked. Strange.

I swapped the safety, along with the detent and spring, with another Colt safety as well as a BAD ambi, making sure to point the detent’s pointy side towards the selector. Same thing with both.

I then put the safety into a known good rifle and it works fine. This leads me to assume that the safety selector itself is fine.

I then compared the entire trigger assembly to another 6920 that I have and everything looks identical. Springs, etc. are all in the right place and in-spec.

This particular rifle only has a couple hundred rounds through it with no issues whatsoever. It’s been so long since I’ve handled it that I cannot remember if this issue existed when I put it away in the safe.

I’ll post some pictures when I get home. In the meantime, any suggestions on what it could be?

Here are some pics:












2

EDIT DERP, I didn’t read carefully enough… nevermind.

3

Did you pull the trigger out and look at it…or just look in the lower? Pull it out if you haven’t, and take a good look. Is it the stock colt trigger assembly?

Does your trigger pin hole look oversized? Selector cut in the receiver looks good?

pics should help.

good luck!

4

Does it do this with BAD Ambi or with the stock one only?

5

I haven’t pulled anything yet… I’ll try later. Stock trigger assembly. Pin holes look just fine.

6

Both. I should have been clearer… It usually has the stock assembly. I tried a second stock assembly as well as the ambi just to rule out the original stock assembly.

7

your trigger or your selector, or both, are out of spec…

8

Something ain’t right here…

What you are describing can’t happen with a bone stock Colt.

9

I think I detected something. He has KNS pins on there which indicates that it isn’t stock. If this was a .169 lower and someone installed .155 inch pins, would there not be enough room to allow the selector to move over the tail area of the trigger? Just thinking aloud since I can’t see the gun.

10

this was my first thought when i read the OP

11

OP, that trigger doesn’t look right in your pictures. The rearmost part that extends under the safety appears to be half missing. Pull the trigger assembly and post some pictures. My bet is that you got a bad trigger from the factory.

12

I think I just saw it. The left side of the trigger tail appears to be completely missing.

13

Absolutely… Good catch.

Normal, it’s a large pin Colt.

14

I tried the kns pins on a whim, thinking the stock pins may be bad. I just didn’t change them back when I took the pics. Yes, it is a large pin colt and I am using .170 pins.

I am meeting with a smith on Monday… Too weird for me…

15

No need for a gunsmiff…

The fix here is simple, get rid of the KNS crap and put the OEM safety selector and trigger parts back in.

16

I never knew that. Not to derail the thread, but was the chopped tail done as one more step to neuter the AR 15 during that time?

17

Yes… All of the 0.170 triggers were manufactured like that. They were originally designed to be used in conjunction with the infamous Colt sear block which prevented a full auto trigger from being used. Even after sear blocks were discontinued, Colt continued to used the trigger because there was no need to change it to work with a lower receiver that didn’t have a sear block.

18

Shows what I know. I haven’t messed with a .169 FCG in so long I completely lost sight of the neutered trigger.

19

I think Sweeney talks about all the Colt FCG differences in his book.

20

Thank you all for your help! It seems it was a very simple issue that was very easy to miss…

Apparently there was a tiny burr in the channel housing the safety retaining pin spring that was rubbing up against the spring. A small file and five minutes and everything works just fine now. With and without the kns pins:D!