AR15 safety / trigger problems, help!

[That_FNG]

So my problem child AR15 has developed a new problem. I solved one problem for another one to surface.

The Gun:
300 Black Out Build.

Anderson milspec upper and lower,
CMMG milspec lower parts kit
CMMG milspec trigger
Stag Arms milspec buffer tube and weight,
Midwest industries handguard
fixed Magpul pmag.
CMMG 16" barrel
Nemo Arms 300 black out specific buffer spring.

So the original problem was the gun was short cycling where it would not always load a new round from the magazine. I replaced the Milspec buffer spring with a Nemo Arms 300 Black Out specific spring and it solved that issue. The gun cycles everything, including 220gr subsonic.

Now I have run into an issue where after firing a round the safety seems to engage. Basically I would load the gun, fire the first round and then when I would go to fire the second round the trigger would be dead. I would then open the action and see that the hammer has indeed reset but somehow the safety has engaged. I would then disengage the safety and the gun would then fire even though my finger was not on the trigger. Basically like the safety is holding the trigger back, and by releasing the safety the hammer then falls, firing a round.

Thoughts?

 

[Bushmaster]

Buffer spring change,weight, or trigger group installed wrong with spring?

 

[cgrutt]

Sounds really odd. I don't know why safety would engage after firing are you sure you are not moving it from fire to safe? Is there excess play in it? Safety will limit trigger mechanism from travelling up when engaged. It should not physically touch trigger mechanism so should have no impact on it when moving from safe to fire. Possibly a worn trigger sear/hammer engagement?

 

[dsdmmat]

Pull your trigger group out of the gun and inspect each part, then reassemble with a book or a diagram in front of you to ensure it is correct. Then recheck at the range.

 

[Bushmaster]

Pull your trigger group out of the gun and inspect each part, then reassemble with a book or a diagram in front of you to ensure it is correct. Then recheck at the range.

I think it's the trigger spring incorrect install.?

 

[dsdmmat]

I think it's the trigger spring incorrect install.?

Possibly but you won't know until you pull it.

 

[Eddie Gunks]

Pull your trigger group out of the gun and inspect each part, then reassemble with a book or a diagram in front of you to ensure it is correct. Then recheck at the range.

^^^^this. Check your disconnector too

 

[spat]

"Have you tried taking it apart and putting it back together ?"

The mechanical equivalent of "Have you tried turning it off and back on again ?".

They are cliche, but only because they are used successfully so often.

 

[meketrefe]

Before you take it all apart just with the lower...
if you push back the hammer what do you see happening?
hold the hammer with your hand and fire when you reset is that
dragging the safety cam around? If so, one of the parts or the position of the holes
could be out of spec.
Even if it doesn't happen in slow motion it doesn't mean it could not happen in fast motion.
But they should not touch unless the safety is on and then the trigger will not budge that is
the only exception.
A trigger is a simple enough mechanism that all that happens in slow motion should be the
same in firing mode given you have it all properly mounted.
Otherwise proceed to disassemble and do it again by the book with a schema in front
if you have to.

 

[That_FNG]

The rifle is a recent build and only has 250 rounds through it. I took apart the trigger group and all looked like it should. The safety in the off position has some play in it. I'm wondering if the safety detent pin and spring are bad? Usually CMMG is good stuff. What worries me is not that the safety is engaging, but why is the rifle firing when you disengage the safety ?

 

[That_FNG]

Before you take it all apart just with the lower...
if you push back the hammer what do you see happening?
hold the hammer with your hand and fire when you reset is that
dragging the safety cam around? If so, one of the parts or the position of the holes
could be out of spec.
Even if it doesn't happen in slow motion it doesn't mean it could not happen in fast motion.
But they should not touch unless the safety is on and then the trigger will not budge that is
the only exception.
A trigger is a simple enough mechanism that all that happens in slow motion should be the
same in firing mode given you have it all properly mounted.
Otherwise proceed to disassemble and do it again by the book with a schema in front
if you have to.

When I take the upper off the lower and reset the hammer by hand, all works as it should. When the gun is empty and I use the charging handle to charge the gun with no rounds in the magazine all works as it should. It only does it when you have a loaded magazine inserted into the rifle.

 

[meketrefe]

The rifle is a recent build and only has 250 rounds through it. I took apart the trigger group and all looked like it should. The safety in the off position has some play in it. I'm wondering if the safety detent pin and spring are bad? Usually CMMG is good stuff. What worries me is not that the safety is engaging, but why is the rifle firing when you disengage the safety ?

a bit of play... the safety should not change positions even if you drop the rifle. a bit of slack is ok but nothing should make the cam turn unless you do it
on purpose.
These things are hard to diagnose by words. Any quick videos or pics of what you have might give some light otherwise take this
to a professional or someone with more experience in ARs and triggers ideally.

 

[meketrefe]

When I take the upper off the lower and reset the hammer by hand, all works as it should. When the gun is empty and I use the charging handle to charge the gun with no rounds in the magazine all works as it should. It only does it when you have a loaded magazine inserted into the rifle.

the magazine has zero impact on the trigger group. something else is going on.

 

[Bushmaster]

is the dis-connector spring in backwards?

 

[GUNSICK]

Wrong spring for the safety or its binding. Check it out.

 

[Bushmaster]

Wrong spring for the safety or its binding. Check it out.

That sounds good also, IDK I give up lol. But why's it charge and fire like auto when safety is released? charged and Bump fired LOL

 

[That_FNG]

is the dis-connector spring in backwards?

I don't believe so, but I'm going to be checking everything again.

Wrong spring for the safety or its binding. Check it out.

I'm thinking one of these two might be the issue. This is the 15th AR I have built, and the first one to give me problems. Granted all the others have been .223 wylde guns but that should not make a difference in this regard.

I'm thinking that I am just going to strip the lower out, and install new parts.

 

[That_FNG]

That sounds good also, IDK I give up lol. But why's it charge and fire like auto when safety is released? charged and Bump fired LOL

I suppose you are correct, bumpfire would be more correct seeing as how nothing was touching the trigger. It once fired two shots in a row like full auto without anything touching the trigger.

 

[gqllc007]

It's the safety detent and spring