Problem with AR double firing

nhn2a

Ten Pointer
I went out and did some shooting today with my 300 Blackout. However I ran into some odd behavior. About 30% of the time, the gun would double fire and technically would attempt to triple fire. By this I mean when I pull the trigger it would fire the first round, cycle, fire a 2nd round, cycle, and then light strike the primer on a third round. I'm about 90% sure its the drop in trigger but wanted to get others opinions also before I contract the company. Its an Aero Precision build (upper, lower, and BCG) with a JMT Saber drop in trigger. It did this with three different types of ammo so I dont believe the ammo is the cause. Anyone else ever seen this behavior before?
 
Mr.Gadget

Mr.Gadget

Old Mossy Horns
Something is up with your trigger.
Drop in another and see if that corrects it.
Lot of the Match triggers are so light and short pull, when shooting on a bench or braced good it will double tap, bump fire.

Try another trigger and see, if it works good you may need to adjust your current or replace.
Also you can try freehand shooting and pull the trigger not a bench type but just quick pull. See if that changes it.
 

nchunter

Twelve Pointer
I do remember a story of that happening to a guy at a range.
Law enforcement guy was also there and arrested him for possession of an automatic weapon (whatever the charge is? WMD?).
Be aware of that.


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nhn2a

Ten Pointer
nchunter said:
I do remember a story of that happening to a guy at a range.
Law enforcement guy was also there and arrested him for possession of an automatic weapon (whatever the charge is? WMD?).
Be aware of that.


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Click to expand...

Good thing I'm at my own property and not a public range then. I'd hope some common sense would prevail and someone could show that it was a defect and not intentional but who knows.
 

nhn2a

Ten Pointer
Mr.Gadget said:
Something is up with your trigger.
Drop in another and see if that corrects it.
Lot of the Match triggers are so light and short pull, when shooting on a bench or braced good it will double tap, bump fire.

Try another trigger and see, if it works good you may need to adjust your current or replace.
Also you can try freehand shooting and pull the trigger not a bench type but just quick pull. See if that changes it.
Click to expand...

Thanks! I was shooting from a bench so the bump fire is a possibility. The saber trigger doesnt have a short pull but who knows. I've emailed the company to see what they say. I looked up some reviews last night and I found a few others with this exact same trigger reporting the same.
 
TravisLH

TravisLH

Old Mossy Horns
Mr.Gadget said:
Something is up with your trigger.
Drop in another and see if that corrects it.
Lot of the Match triggers are so light and short pull, when shooting on a bench or braced good it will double tap, bump fire.

Try another trigger and see, if it works good you may need to adjust your current or replace.
Also you can try freehand shooting and pull the trigger not a bench type but just quick pull. See if that changes it.
Click to expand...

Yup, I’ve had one that would fire full auto..... swapped out the disconnect or and prob solved


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UpATree

UpATree

Ten Pointer
Contributor
I bought a very used one of the first Barnes Precision’s, I think the serial number was around 700. If you held the trigger just right, about halfway, you could get 3-4 shots off with one squeeze. I called Barnes and made an appointment for them to look at it, since they are in Apex and I’m in Cary. I was met by Andrew Barnes, who took it back while I waited in their lobby. Fifteen minutes later he came back having replaced the trigger and even test fired it. Despite the age of the rifle, all it cost me was a handshake and I was out the door. No paperwork or anything. Nice.
 
Infamous1

Infamous1

Eight Pointer
UpATree said:
I bought a very used one of the first Barnes Precision’s, I think the serial number was around 700. If you held the trigger just right, about halfway, you could get 3-4 shots off with one squeeze. I called Barnes and made an appointment for them to look at it, since they are in Apex and I’m in Cary. I was met by Andrew Barnes, who took it back while I waited in their lobby. Fifteen minutes later he came back having replaced the trigger and even test fired it. Despite the age of the rifle, all it cost me was a handshake and I was out the door. No paperwork or anything. Nice.
Click to expand...
You are not the only one I have heard of this happening to!!
 
Eric Revo

Eric Revo

Old Mossy Horns
Contributor
I've got an older Ruger mini-30 that will do that occasionally, it makes for a tightened sphincter if you're not prepared for it. It will sometimes fire single for awhile then decide to double or triple tap. I thought about sending it back to Ruger, but where's the fun in that?
 

nhn2a

Ten Pointer
I contacted JMT today and they gave me some step by step instructions on how to adjust the disconnector spring which is what they believe the problem is. They said if it happens again after that they will RMA it and check it out completely.
 

nhn2a

Ten Pointer
Well even after adjusting the disconnector spring it still performed the same way. Called the company today and they are sending me a shipping label to send it back so they can go over it. In the meantime, I threw in a RA-140 drop-in I also had and it worked perfectly at the range so definitely is the trigger.
 
TravisLH

TravisLH

Old Mossy Horns
nhn2a said:
Well even after adjusting the disconnector spring it still performed the same way. Called the company today and they are sending me a shipping label to send it back so they can go over it. In the meantime, I threw in a RA-140 drop-in I also had and it worked perfectly at the range so definitely is the trigger.
Click to expand...

Sometimes it’s just weird .... I’ve used the same parts from my experience in other builds (just not together) and they worked fine


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woodmoose

woodmoose

Administrator
Staff member
Contributor
I've seen folks accidentally double tap with low trigger pull and and no follow thru,,,,not meaning to but their trigger finger follow through was soft, their finger bounces off the front of the trigger guard, back into the trigger, and off goes another round,,,

taught them to pull to the rear and stay there,,

no more issues

of course that's not what happened here,,,,
 
Mr.Gadget

Mr.Gadget

Old Mossy Horns
nhn2a said:
When you say case, what are you referring to? Ammo casing or the case of the drop-in?
Click to expand...

In this case.
The tolerance on the parts have a plus and minus.
When you build the group lets say the parts used were on the minus side, smaller overall size then the gap becomes larger between parts that are not on the same center line and rotational point.

Think of it this way. If you had a yardstick that was just a little short. You cant really see it. You will not really know it and over all not much differance.
Use that yard stick to lay out 100 yards you are 100x the difference it was short and it is way off.
 
Infamous1

Infamous1

Eight Pointer
woodmoose said:
I've seen folks accidentally double tap with low trigger pull and and no follow thru,,,,not meaning to but their trigger finger follow through was soft, their finger bounces off the front of the trigger guard, back into the trigger, and off goes another round,,,
Click to expand...
Got a terrible case of the scope eye from doing that the first time I shot my 7400 after a smith smoothed and lightened the trigger. Tough lesson to learn!!
 

nhn2a

Ten Pointer
I know what you're saying, but I don't think that's the issue but possibly.
Mr.Gadget said:
In this case.
The tolerance on the parts have a plus and minus.
When you build the group lets say the parts used were on the minus side, smaller overall size then the gap becomes larger between parts that are not on the same center line and rotational point.

Think of it this way. If you had a yardstick that was just a little short. You cant really see it. You will not really know it and over all not much differance.
Use that yard stick to lay out 100 yards you are 100x the difference it was short and it is way off.
Click to expand...

It's possible but I tend to think something else may be the cause. The trigger worked as expected for the first couple years I had it and is now failing without any visible sign of wear or out of tolerance.
 
Mr.Gadget

Mr.Gadget

Old Mossy Horns
nhn2a said:
I know what you're saying, but I don't think that's the issue but possibly.


It's possible but I tend to think something else may be the cause. The trigger worked as expected for the first couple years I had it and is now failing without any visible sign of wear or out of tolerance.
Click to expand...
10-4 keep us posted. Something changed in the trigger if it worked then started having problems.
Could be anything from heat treat, out of spec or close to when new so little wear on it or spring problems.
Did you check trigger pull new, and current? Wonder if the spring was weak or.bad.

Some times the wear can be very hard to see and if you don't have a blueprint it is hard to check and know what is good or bad, and if it is in spec.
 
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