AR15 Unwanted Burst Fire with CMMG .22 Conversion

danoiwan

danoiwan

CGN Regular
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Location
Ottawa, Ontario
I have a Dominion Arms DA556, I got the CMMG .22 Conversion kit, but the hammer isn't always getting cocked after each shot. Because of that, I get a 2 shot burst sometimes. After doing some research and inspecting all the parts, the problem seems to be the notched hammer that my rifle has. With the notch on the hammer, there is less surface area for the .22 bolt to catch and sometimes the bolt and hammer are just slipping/skipping off each other. I have a new hammer on the way and I will follow up to ensure that it solves the problem.

Needless to say, people at the range were quite surprised and so was I.

******Update on post 18******

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I had this happen a few times on my M305, RO at the range asked, because the rule of 3 second time frame between shots. It has not happened for a while now. Maybe my trigger finger was a little jumpy. My trigger on mine feels more precise than my buddies.
 
J Ace said:
I had this happen a few times on my M305, RO at the range asked, because the rule of 3 second time frame between shots. It has not happened for a while now. Maybe my trigger finger was a little jumpy. My trigger on mine feels more precise than my buddies.
Click to expand...

Oh my. f:P:
 
Back on topic, my CMMG conversion has gone "burst" one or twice in the ~500 rounds that I've put through it since buying it new.

The first time it happened I barely noticed it, it just sounded funny. The next range outing it happened again and the only reason I clued in was because of seeing the two brass casings being ejected. It hasn't happened since and I've never had the problem when running .223. Not sure what's up.

I'd be a little more worried about the M305 in case it fires out of battery. I wouldn't think a .22 would be as dangerous.
 
****Update****

So I got a hammer with no notch and a reduced power hammer & trigger spring set. I expected the problem to be gone, but I was wrong. I started using my CMMG conversion kit with winchester white box and had very little problems. Only once and a while it would not re-#### the hammer. Then I switched to federal bulk and that is when the burst fire started. I noticed that the federal ammo has a lower fps then the winchester. I did some more research and found that cutting off some of the coils off the recoil spring of the conversion kit was a common solution. So off to the range again. I ended up cutting off 10 or 11 coils and now it works flawlessly.

So the trick is, buy the ammo with the lowest fps, then tune the recoil spring to that ammo and you will be good to go with anything. If you don't have the stainless conversion kit, polish the paint off the rails as well.
 
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