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Posted: 3/16/2015 8:01:38 PM EDT
| Does anyone here run a CMMG 22LR upper on their M16? If so which one do you use? As well as any comments on FA use with these uppers. |
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I have a dedicated cmmg upper with stainless internals. I shortened the barrel to 4.5 inches. It runs like a scalded dog. Shoots every brand of ammo even the cheap stuff. My lower is a colt m16a1.
It took some work to get it to run. When I got the kit it would not even fire in semi auto. Shoot me an email and I will send you a list of what I did to get my gun to run. |
| I have a 16" cmmg upper and a 4.5" I run with a sparrow. They are quite possibly the most fun gun to shoot full auto. Kind of like the bb machine gun at the carnival you try to shoot out the red square with. That said they are very finicky. Ammo, springs, everything seems to make a difference in full auto. I got mine to work 99% for thousands of rounds. I put an SSF trigger in and first magazine it quit firing. When I got home the firing pin was broken and also one leg of the auto sear trip. These were replaced right away, thank you Tim at Taccom and CMMG, and I'm sure it had nothing to do with the SSF. Now I have 3 variables and am having a tough time getting it to run again. Perfect in semi though. Bob |
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Quoted:
I have a dedicated cmmg upper with stainless internals. I shortened the barrel to 4.5 inches. It runs like a scalded dog. Shoots every brand of ammo even the cheap stuff. My lower is a colt m16a1. It took some work to get it to run. When I got the kit it would not even fire in semi auto. Shoot me an email and I will send you a list of what I did to get my gun to run. Why not post it here so we can all learn? Unfortunately the two .22 uppers/guns I own aren't FA compatible, so getting info on making a CMMG-type upper that can run on bulk ammo would be super helpful. |
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Why not post it here so we can all learn? here are some options that I found, only some are necessary since these things are finicky. mind you I'm no pro and my terminology and advice is worth what you paid: most common issue is bolt bounce. there are several ways to alleviate this but a como of the following should resolve: the sear trip is mandatory the bolt bounce weight is usually mandatory (not on mine) get longer, stronger bolt springs and start with those and cut to length using trial and error if a dedicated lower, you can bend the hammer springs legs with a 15deg or so bend, thus weakening them. I did this in addition to using JP lighter springs. it allows the hammer to reset with less force but still plenty to strike the firing pin I have heard some use a plug in the buffer tube area to keep the bolt from moving, not required on mine enhanced firing pin 22lr dedicated charging handle if rounds get jammed up there frequently ammo, mine doesn't run anything Remington. Federal, CCI, Winchester are all G2G some bolts (spikes) have a ball detent mod to try to control bolt bounce if you find your hammer is falling on a light primer strike (the stronger spring fixed this for me) I get 99% function with sear trip, the strongest spring I have, no bolt bounce weight, using JP lighter power springs with bent 15deg hammer spring, and using an enhanced firing pin. that's it BUT it took a lot of swapping and usage to figure out what works. the best way is to start, imo is with what you have and go down the list to alleviate any problems that occur in the end, it will be worth it 
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I haven't done this yet, but to the poster just above, here is a link to a company that sells a reliability kit, almost everything mentioned.
http://www.taccom3g.com/22rf-reliability-kit.html Another thing to watch out for is the anti bounce weight may become damaged from use. Mine eventually caused my bolt to lock to the rear. This occurred after about 3-4K rounds. |
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Here you go. Mine runs great with 50 round drums from black dog. I am using cheap ass remington bullets.
Here is what I ended up having to do to mine to get it to work. The 1st trip I got was way out of spec. I tried bending it to get the timing right but I broke it. I ordered a new trip and it worked right out of the package. Replaced firing pin with Taccom pin. Use Taccom plug when upper is in gun. This made a big difference. Switch to a JP enterprise med weight hammer spring. Cut about 1/3 off the firing pin spring. Replaced recoil spring with one from Lakeside Machine Replaced Disconnector spring with one from lakeside With a dremmel and jeweler’s rouge I polished the following: The receiver frame rails where the bolt contacts (22 kit receiver) The rear of the bolt The feed ramp The entire firing pin so it would move freely in the firing pin slot when spring was out. The front of the colt factory hammer. This helped tremendously The bottom of the anti bounce weight so it will slide in its spot easily I also used a fine gunsmith's file on the area of the bolt that runs along the receiver frame. The anti bounce weight was contacting the upper receiver on the gun so I took some 200 grit paper and sanded the edges of the serrations on the anti bounce weight that make the forward assist work. To work correctly the weight needs to be able to move freely in its slot in my opinion. |
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