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Badkarma3015
05-27-2011, 9:03 AM
I am new to Calguns and I have an AR15 problem.

I have a DSarms lower and a DPMS lower parts kit. I have fired my AR a few time and never had a double tap but my friends have. Yesterday I was out shooting and my AR fired twice when I pulled the trigger. I changed the magazine and fired again and the same thing happened. I then pulled the trigger and held it back and then released and it fired again. It is not the magazine or the ammo I am using. I have check all the springs and they are in the correct place and not upside down.

Thank you for your help.

EBR Works
05-27-2011, 9:05 AM
You most likely have a problem with the disconnector or the associated spring. Take the FCG apart and fix it ASAP. Don't shoot it until this issue is resolved by you or a competent gunsmith. Have you done a function test on the lower?

How to do the function test is here at 4:40:

l4uiPXuyUAU

dieselpower
05-27-2011, 9:15 AM
I then pulled the trigger and held it back and then released and it fired again

worn hammer/disconnector trigger. When you release the trigger it releases the hammer, the disconnector trigger grabs the hammer and waits for the trigger to pull back again.
Replace your disconnector trigger and hammer.

Badkarma3015
05-27-2011, 9:18 AM
Yes I have done a function check and it works just fine.

dieselpower
05-27-2011, 9:25 AM
Yes I have done a function check and it works just fine.

No it doesnt...

There is a small notch on the bottom of your hammer where the trigger catches it after the disconnector lets it go. the hammer or trigger is not grabbing each other. Ignore my first post, if the weapon stop firing while the trigger is held back, the disconnector is fine..sorry not enough coffee.

dieselpower
05-27-2011, 9:28 AM
http://www.bushmaster.com/anatomy_bushmaster.asp

hide everything and watch the mechanical action of the LPK. If your firearm fires when the trigger is released, the trigger and hammer are not catching at the bottom.

Badkarma3015
05-27-2011, 10:16 AM
I'm going to get a replacement lower kit and change everything out.

Thanks for all your help.

OHW
05-27-2011, 10:45 AM
The disconnector spring has a large side and a small side. If it in upside down a malfunction like the OP described can happen.

Big side goes down. If it is up it hangs up on the knob at the bottom of the disconnector.

It is an easy thing to miss on assembly. GLTY

G38xOC
05-27-2011, 7:39 PM
Imana say its ur hammer is out of spec

dieselpower
05-27-2011, 8:04 PM
The disconnecter spring has a large side and a small side. If it in upside down a malfunction like the OP described can happen.

Big side goes down. If it is up it hangs up on the knob at the bottom of the disconnecter.

It is an easy thing to miss on assembly. GLTY
I am sorry, but No it can not. You too need more coffee. The only time a upside down disconnecter spring or worn disconnecter can cause a string is on the trigger pull. After the pull and during forward movement the notches control the hammer.

rodeoflyer
06-26-2011, 3:55 PM
http://www.bushmaster.com/anatomy_bushmaster.asp

hide everything and watch the mechanical action of the LPK. If your firearm fires when the trigger is released, the trigger and hammer are not catching at the bottom.

I had the same issue today at the range. I disassembled my lower and decided I believe the hammer is worn or out of spec.

I was researching and found this thread. Very helpful and appreciate the Bushmaster link.

I am a little disturbed in that the parts kit is new (Stag, under 1k rounds). I did notice that the hammer in my DPMS lpk in my other lower seems to be "beefier" on the catch lip for the disconnector.

1. Is this common?

2. Is this common with Stag? Other brands?

3. Are there lpk's (not including fancy triggers) that TRULY are worth the extra money, and why?

Thanks.

CK_32
06-26-2011, 3:59 PM
Tag.

rodeoflyer
07-05-2011, 3:37 PM
Tag.

Update, for your amusement. :rolleyes:

Hammer was fine. Ended up being a bad disconnector spring. It was installed correctly, but it was an 1/8 inch short, and was weak. Rather irritating considering it only had 1000 rounds on it.

luckystrike
07-05-2011, 4:52 PM
backwards hammer spring?

motorwerks
07-06-2011, 10:30 AM
backwards hammer spring?

look up one post.

luckystrike
07-06-2011, 3:04 PM
look up one post.

oops:D

cabinetguy
07-06-2011, 3:52 PM
delete this thread. there is a inherent danger of people that might try this to make a illegal nfa, and that would set us all back. sure the op is trying to fix an issue, but if the backwards springs makes a nfa, wait it till the antis get a hold of that info. yes its a common mistake, yes it happens when you dont want it to, but still

rattlesnake_nm
07-06-2011, 3:56 PM
Sad.

Army
07-06-2011, 4:41 PM
delete this thread. there is a inherent danger of people that might try this to make a illegal nfa, and that would set us all back. sure the op is trying to fix an issue, but if the backwards springs makes a nfa, wait it till the antis get a hold of that info. yes its a common mistake, yes it happens when you dont want it to, but still
No no no! Here on Calguns, we ''mind your own business'' when we see a fellow shooter inadvertently breaking the law. You must not help out an otherwise law abiding gun owner, that would be much too neighborly and polite.

:rolleyes:

-hanko
07-06-2011, 7:37 PM
delete this thread. there is a inherent danger of people that might try this to make a illegal nfa, and that would set us all back. sure the op is trying to fix an issue, but if the backwards springs makes a nfa, wait it till the antis get a hold of that info. yes its a common mistake, yes it happens when you dont want it to, but still
I'd check for an upside-down disconnector spring first, and this info has been posted on the web a few zillion times before this thread.;)

Anecdotal testing with a friend indicates it's not a reliable way to get fa cycling...you'd need a Lightning Link, drop-in-auto-sear (dias), or a receiver with a hole to accept an auto sear and the other associated parts; any of which are nfa items.

"Friend" is also licensed to both sell and produce nfa items.

hth

-hanko