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9/22/2017 12:11:25 AM
Posted: 8/27/2005 7:18:59 AM EDT
A few weeks ago, my rifle was inadvertently"Bump firing". I was under the assumption that maybe my FCG was starting to wear out, so I purchased a RRA 2-stage trigger tuned by WOA. I had the rifle out yesterday for the first time since installing the new FCG, and guess what, the rifle was "bump" firing again.

The rifle has had about 5k rounds of PMP .223 through it without any problems. I ran through my last few rounds of this, and ordered some FAE .223 with LC 04 brass. The problem has only appeared once I switched to the new ammo.

Anyone have any thoughts as to what is going on here?
Link Posted: 8/27/2005 7:54:04 AM EDT
Let me guess, you replaced the trigger and hammer, but left in the old disconnector and spring...

Am I close?
Link Posted: 8/27/2005 8:35:18 AM EDT
Sorry, but no, I replaced the entire FCG; H,T,D, and springs.
Link Posted: 8/27/2005 8:43:50 AM EDT
Check the spring on your disco and make sure it is seated and inserted correctly.


Have you done a proper function check of the weapon?
Link Posted: 8/27/2005 9:09:48 AM EDT
[Last Edit: 8/27/2005 9:19:25 AM EDT by _DR]
If it is doubling or tripling without you doing it intentionally, this is not "bump firing". Two or three rounds per single trigger pull is a condition you should remedy ASAP as a certain gubmint agency may consider this an illegal MG. You don't want to spend quality time with Bubba in Club Fed over a few dollars worth of FCG parts malfunctioning.

You might want to take out the FCG group completely and reassemble carefully following these instructions very carefully.

Then do your function check as Stick suggested:

Link Posted: 8/27/2005 2:33:05 PM EDT
[Last Edit: 9/4/2005 10:28:21 AM EDT by Tweak]
Link Posted: 8/27/2005 7:24:39 PM EDT
Is it an adjustable trigger group???? If it is, you are not adjusting it properly (probably too light of a pull). Re-check your adjustments.
Link Posted: 9/3/2005 6:56:12 PM EDT
Ok, I've done the function test as stated above. Took my rifle to the range again today, and the problem is still there. _DR stated I should take the FCG group out and reinstall. I simply "dropped" the trigger group into the lower as soon as I removed it from the package.

Is there something else I should be looking for?
Link Posted: 9/3/2005 7:06:34 PM EDT
I have wondered about this, when this happens, isnt it possible for you to have an out of battery detonation? or is that not possible, or just not likley, cause i mean if it was possible, wouldnt it be dangerous to even hold the gun while testing it if it was shooting like that?
Link Posted: 9/3/2005 7:11:23 PM EDT
Post it in troubleshooting and answer Tweak's question. That's the best advice I can give you at this point.
Link Posted: 9/3/2005 7:20:21 PM EDT
[Last Edit: 9/3/2005 7:21:29 PM EDT by theshootersden]
Hey Tweak, is it possible for the firing Pin to some times stick in the fired position, making it act like an open bolt?
Link Posted: 9/3/2005 7:23:38 PM EDT

Originally Posted By theshootersden:
Hey Tweak, is it possible for the firing Pin to some times stick in the fired position, making it act like an open bolt?



I'm not Tweak, but AFAIK that is not possible. The way the cam rotates the firing pin must move back when the bolt goes out of battery.
Link Posted: 9/3/2005 7:54:38 PM EDT

Originally Posted By theshootersden:
Hey Tweak, is it possible for the firing Pin to some times stick in the fired position, making it act like an open bolt?



Not Tweak either, but none of the military or LE/ Colt armorer schools have thought it was an issue.

I would think an out of spec part would be a closer bet (ie pin or bolt) if you were looking at that angle. Odds wouldn't be good.



Opey, check the FCG for any metal shaving, dirt of debris. How sure are you that the disco spring went in the right way?






Link Posted: 9/3/2005 8:10:33 PM EDT

Originally Posted By Stickman:

Originally Posted By theshootersden:
Hey Tweak, is it possible for the firing Pin to some times stick in the fired position, making it act like an open bolt?



Not Tweak either, but none of the military or LE/ Colt armorer schools have thought it was an issue.

I would think an out of spec part would be a closer bet (ie pin or bolt) if you were looking at that angle. Odds wouldn't be good.



Opey, check the FCG for any metal shaving, dirt of debris. How sure are you that the disco spring went in the right way?

www.airforcesecuritypolice.com/invisionboard/uploads/post-3-1095318815.jpg


www.airforcesecuritypolice.com/invisionboard/uploads/post-3-1095318886.jpg




Im picking up what your laying down... What has me thinking its something other than a FCG issue is that he had switched to a RRA 2-stage trigger and is still experiencing bursts... As you already know, those are a lot different than the standard FCG's with its separately pinned disconnect setup... It very well could be a disconnect debris, spring issue like you said...
Link Posted: 9/3/2005 8:15:04 PM EDT
[Last Edit: 9/3/2005 10:01:09 PM EDT by Stickman]
He wouldn't be the first person to have not cleaned a FCG before install and ended up with shavings stuck to the parts.....


I still think he should pull the disco spring, or if he pulled and doubled checked it, I must have missed that part.
Link Posted: 9/3/2005 8:16:04 PM EDT

Originally Posted By Stickman:
How sure are you that the disco spring went in the right way?



Stickman's on the right track. An upside down disconnector spring could cause this exact problem.
Link Posted: 9/3/2005 8:16:43 PM EDT
I forgot to mention in my last post.... I'm assuming that he originally was using a standard FCG and then switched to a 2-Stage FCG...
Link Posted: 9/3/2005 8:24:11 PM EDT
[Last Edit: 9/3/2005 8:25:33 PM EDT by theshootersden]
I hope the disconnect pin doesn't bugger up for him if he removes the pin, WOP flattens the tip of the pin after reassembling the trigger...

Do either of you guys know if RRA sells replacement pins for their disconnects? I wanted to ask them the last time I had them on the phone but forgot...
Link Posted: 9/3/2005 8:53:38 PM EDT

Originally Posted By Opey:
A few weeks ago, my rifle was inadvertently"Bump firing". I was under the assumption that maybe my FCG was starting to wear out, so I purchased a RRA 2-stage trigger tuned by WOA. I had the rifle out yesterday for the first time since installing the new FCG, and guess what, the rifle was "bump" firing again.

The rifle has had about 5k rounds of PMP .223 through it without any problems. I ran through my last few rounds of this, and ordered some FAE .223 with LC 04 brass. The problem has only appeared once I switched to the new ammo.

Anyone have any thoughts as to what is going on here?



The new ammo might have soft primers... The force of the bolt and carrier slamming shut causes the firing pin to tap the primer...Try different ammo to see if it corrects the problem...
Link Posted: 9/4/2005 5:12:03 AM EDT
[Last Edit: 9/4/2005 5:27:15 AM EDT by Opey]
Stickman,

As per the instructions on the Do it your self section here, I cleaned the FCG with CLP prior to installing. This morning I took the FCG out again, cleaned again, checked the FCG for any metal shaving, dirt and debris. I cannot see a way to check if the disco spring went in the right way, as there doesn't seem to be away to remove it, as someone stated, the pin is flattened (this is how it came from ADCO, the FCG is a RRA 2-stage trigger tuned by WOA).


theshootersden,

you are correct, my rifle had the original, standard FCG and I then switched to a 2-Stage FCG once the problem started happening. This again started happening once I switched to FAE .223 with brass stamped with the NATO symbol and LC04. Like previously mentioned, I was using PMP .223, and ran through about 5k rounds with no problems. I'm going to use some XM193 and Q3131(a) my next time out to the range, just to see if its the new ammo thats giving me the problems.

Thank you to everyone for their help.



Link Posted: 9/4/2005 5:42:43 AM EDT
[Last Edit: 9/4/2005 5:51:57 AM EDT by theshootersden]
Opey,
As you have discovered, the disconnect and spring used with the RRA/WOP 2-stage trigger can not be easily removed... It can be done but you stand a chance of damaging the disconnect pin... There is no need to look to see if the spring is installed upside down because there is no upside down... The spring is the same size from end to end and it makes no difference which way it is installed...

I would completely strip the bolt from the carrier and give all the parts a good looking over to see if there are any visual defects... If everything checks out OK, then I would clean and lubricate the parts before re-assembling them... And as I had already mentioned, you might want to look into the ammo as being the cause of the trouble you are experiencing... Good luck...
Link Posted: 9/4/2005 10:33:41 AM EDT
Link Posted: 9/4/2005 10:46:16 AM EDT

Originally Posted By Tweak:

Originally Posted By theshootersden:
is it possible for the firing Pin to some times stick in the fired position, making it act like an open bolt?



I have seen a broken firing pin do that but never an intact one.



Thats what I had thought, that the burst could possibly be contributed to the pin
Link Posted: 9/4/2005 1:26:48 PM EDT

Originally Posted By theshootersden:
The spring is the same size from end to end and it makes no difference which way it is installed.



Just to clarify so that others do not get confused, the factory disconnector springs are different sizes on the ends, and must go in with the fatter side down.
Link Posted: 9/4/2005 3:28:03 PM EDT
[Last Edit: 9/4/2005 3:31:30 PM EDT by theshootersden]

Originally Posted By M4Madness:

Originally Posted By theshootersden:
The spring is the same size from end to end and it makes no difference which way it is installed.



Just to clarify so that others do not get confused, the factory disconnector springs are different sizes on the ends, and must go in with the fatter side down.



Yes, that is correct about the original factory disconnect spring... And to clarify so that others do not get confused, my quote that M4Madness is using as an example, is referring to the RRA 2-stage disconnect spring that we were discussing, which is the same size from end to end...
Link Posted: 9/4/2005 4:43:40 PM EDT

Originally Posted By _DR:

Originally Posted By theshootersden:
Hey Tweak, is it possible for the firing Pin to some times stick in the fired position, making it act like an open bolt?



I'm not Tweak, but AFAIK that is not possible. The way the cam rotates the firing pin must move back when the bolt goes out of battery.



Not if the retaining pin for the fire pin is bent locking the fire pin forward. I had an old BM slam fire FA due to this. It wasn't funny at all. In fact I nearly pissed myself.
Link Posted: 9/4/2005 5:01:07 PM EDT
[Last Edit: 9/4/2005 5:08:31 PM EDT by theshootersden]
+1 FL-AR15 on the bent cotter pin... These type of things are exactly why I had asked Opey to inspect the bolt/carrier assembly... Like Tweak and yourself have seen before, certain bolt/carrier assembly parts can malfunction and cause the weapon to go full auto...

You know the more I think about a weapon doing such a thing, the bigger the grin gets on my face... I can almost imagine the expressions on the faces of those that this has happened to, right after "the experience" ... That sure would be a real head turner at my local Rod and Gun club
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