Damaged Disconnector

[gringop]

I posted this on TOS but am not getting much info. I did a quick seach here but didn't find anything.

My gun started doubling at a match so after pulling the FCG I found the disco was peened at the hook and behind the hook on the body where the rear tip of the hammer hits. See pics below. My question is what is causing this. Cheap pot metal disco? Some kind of timing or bad hammer issue? The FCG has at least 1500, maybe 2k rounds though it.
I put in a spare disco but I really want to know what could have caused this. FCG is from Model1Sales.

Lastly, who has good quality discos for sale. I need 3. BCM is out of them. Does Grant sell individual parts or just full LPKs?

Thanks, Gringop

http://i233.photobucket.com/albums/ee238/gringop/IMGA0092a.jpg
http://i233.photobucket.com/albums/ee238/gringop/IMGA0097a.jpg

[Buckaroo]

Personally I would jerk this down from the public eye and email Grant or someone else with your questions.

Just my $.02

Buckaroo

[Robb Jensen]

I'd recommend replacing the hammer, trigger and disconnector and related three springs.


The way the trigger mechanism works on a stock AR:

Hammer is cocked, safety is on and a round is chambered.

Shooter moves safety/selector from SAFE to FIRE/SEMI, trigger is pulled releasing the hammer. Firing pin is stuck by hammer. Rifle fires. Bolt carrier moves rearward cocking the hammer. (trigger finger is still on the trigger). Hammer engages the disconnector and stays on disconnector. Rifle finishes the cycling. Shooter releases trigger and the disconnector releases the hammer, the hammer is remaining cocked but connection moves from disconnector to the front of the trigger. Shooter pulls trigger again and repeats the cycle.

http://img.photobucket.com/albums/v408/gotm4/trigger-animation.gif

[ST911]

FCG is from Model1Sales.

And there you have it.

[gringop]

OK, the bad disco hook is peened so it is wider than the normal. It has pronounced ramps on the top and underside of the hook and is worn so the hook is shorter than it should be.
I can tell that the rear tip of the hammer has been hitting the disco. That would tend to move the disco back, causing the disco spring to have to work hard to get the disco forward to contact the hammer hook fully by the time the hammer starts going forward.

Somehow the hammer hook is beating the heck out of the disco hook. My question is is this normal wear, possible being accelerated by having a cheap M1S disco. Would a too fast bolt cycle cause this? Ejection is normal, 8' forward and to the right.


I can pick up a few Bushy discos online and I don't mind paying $10 plus for an LMT disco but I can't find a source for them. If anyone knows of one please let me know.

Trigger and Hammer are absolutely OK, see hammer pic below.

http://i233.photobucket.com/albums/ee238/gringop/IMGA0095a.jpg

[scottryan]

Both of those disconnectors are junk.

One that has your deformed hook and the the other which has the slightly rounded hook on one side.

A disconnecter should be completely flat with sharp edges and with no parting or stamping line.

[Pablo]

Not an uncommon problem with non-milspec parts.

After replacing everything in the FCG with "US" milspec parts (not DPMS stuff) you should be good to go.

The pic of your hammer is showing wear(metal displacement) at the trigger contact edge and will eventually be a source of malfunctions. i.e. unpredictable rounds burst.

[Iraqgunz]

I thought that Model 1 sales was top quality and that any old part will do. Sheesh, I guess I will have to take a look at all of my personal weapons now. Model 1 Kool-Aid, oh yeah.