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Posted: 3/15/2014 9:28:38 AM EDT
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I have a CMMG Alpha conversion bolt that goes auto when I use Federal HV HP (the recommended ammo) and Winchester HV HP ammo. It doesn't happen all the time but maybe 75% of the time. It goes auto until I release the trigger or get a stove pipe or FTF. It functions normally with Golden Bullets, Thunderbolts, CCI Mini-Mags and CCI Blazer.
The upper has a Spike's LE M4 16" barrel with carbine length gas port if that matters. I am assuming the bolt is resetting the hammer far enough to fire the next round but not far enough to engage the disconnector. I have polished and lubed the part of the bolt that contacts the hammer and the hammer face/top edge with no change. Any suggestions? Other than "Don't use Federal or Winchester", I have about 20K rounds of those. |
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I have a CMMG Alpha conversion bolt that goes auto when I use Federal HV HP (the recommended ammo) and Winchester HV HP ammo. It doesn't happen all the time but maybe 75% of the time. It goes auto until I release the trigger or get a stove pipe or FTF. It functions normally with Golden Bullets, Thunderbolts, CCI Mini-Mags and CCI Blazer. The upper has a Spike's LE M4 16" barrel with carbine length gas port if that matters. I am assuming the bolt is resetting the hammer far enough to fire the next round but not far enough to engage the disconnector. I have polished and lubed the part of the bolt that contacts the hammer and the hammer face/top edge with no change. Any suggestions? Other than "Don't use Federal or Winchester", I have about 20K rounds of those. Order some extra springs for when you mess up or want to go back to using regular ammo. Start trimming your recoil spring on the conversion a coil or two at a time to reduce the resistance so that your weak but plentiful ammo can get the hammer back onto the disconnector with every shot. It is also possible to reduce hammer spring resistance by bending the hammer spring legs properly, but shortening the recoil spring is a lot more straightforward and easier to accomplish. CMMG and Taccom both sell replacement spring sets. |
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Even though this is a seemingly unrelated thread, much of what I have brought up in it may help correct the problem you are having.
Any bolt assembly movement in particular can cause problems with hammer reset / disconnect when under recoil. Different ammo will have a different effect on the problem because the recoil force for various velocity ammo reacts differently on the bolt movement. Check a few things mentioned here: http://www.ar15.com/forums/t_3_15/640141_22_Misfires__Light_Strikes__Not_Fully_Chambering_a_Round__Spent_Rounds_Stuck_in_the_Upper.html Dave in Florida |
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Even though this is a seemingly unrelated thread, much of what I have brought up in it may help correct the problem you are having. Any bolt assembly movement in particular can cause problems with hammer reset / disconnect when under recoil. Different ammo will have a different effect on the problem because the recoil force for various velocity ammo reacts differently on the bolt movement. Check a few things mentioned here: http://www.ar15.com/forums/t_3_15/640141_22_Misfires__Light_Strikes__Not_Fully_Chambering_a_Round__Spent_Rounds_Stuck_in_the_Upper.html Dave in Florida I have seen that thread and read it. I had also read about the TACCOM plug so made my own. Cut a 3/4" dowel to length and slipped in down inside the recoil spring so the buffer is tight against the retaining pin and there is no movement. I think it ended up a little less than 3 7/8" long. The bolt assy.. is tight up against the buffer and there is no movement. I ordered a light hammer spring and some of the bolt recoil springs so when they get here I will start trying different things. |
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Remove your firing pin and make the channel is clean and free of debris. Inspect the firing pin spring make sure it's in good condition. The firing pin can become stuck forward when it gets dirty causing the bolt to slam fire. It has done this since it was brand new. Only has about 500-600 round through it right now. Edit: Took the firing pin and spring out. No carbon build up and the spring is in one piece. |
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I had the same problem a few months back with a spikes lower. The disconnect or spring was short. Try replacing your 50 cent spring before anything costly. I have tried the upper on 2 lowers, one with a ALG Defense QMS trigger kit and one with a CMMG LPK trigger but I will replace the disconnector spring when I get the light hammer spring kit from Brownell's. |
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Quoted: Remove your firing pin and make the channel is clean and free of debris. Inspect the firing pin spring make sure it's in good condition. The firing pin can become stuck forward when it gets dirty causing the bolt to slam fire. I don't see firing pin springs listed on your web site. How can I get a couple of spares? |
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Problem solved.
Installed a reduced power disconnector spring as m200maker suggested and polished the hammer/disconnector contact surfaces. That got me down to 2 shots fired for every trigger pull with Federal. Every single time. Next I bent the hammer spring about 90 degrees to reduce the force on the hammer as Circuits suggested and that got me running 100% with the Federal. With M22 I had a light strike about 1 in 5 and with Thunderbolts I had light strikes every other time. Bent the hammer spring back to about 45 degrees off original and it works 100% with all brands I have in house. Thanks for all your suggestions. 
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Quoted:
I don't see firing pin springs listed on your web site. How can I get a couple of spares? Quoted:
Quoted:
Remove your firing pin and make the channel is clean and free of debris. Inspect the firing pin spring make sure it's in good condition. The firing pin can become stuck forward when it gets dirty causing the bolt to slam fire. I don't see firing pin springs listed on your web site. How can I get a couple of spares? If you can't get them from CMMG I found a kit on Midway that has 2 each recoil, firing pin and extractor springs. http://www.midwayusa.com/product/960880/cmmg-22-long-rifle-ar-15-conversion-kit-survival-spring-kit?cm_vc=ProductFinding |
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Quoted: If you can't get them from CMMG I found a kit on Midway that has 2 each recoil, firing pin and extractor springs. http://www.midwayusa.com/product/960880/cmmg-22-long-rifle-ar-15-conversion-kit-survival-spring-kit?cm_vc=ProductFinding Quoted: Quoted: Quoted: Remove your firing pin and make the channel is clean and free of debris. Inspect the firing pin spring make sure it's in good condition. The firing pin can become stuck forward when it gets dirty causing the bolt to slam fire. I don't see firing pin springs listed on your web site. How can I get a couple of spares? If you can't get them from CMMG I found a kit on Midway that has 2 each recoil, firing pin and extractor springs. http://www.midwayusa.com/product/960880/cmmg-22-long-rifle-ar-15-conversion-kit-survival-spring-kit?cm_vc=ProductFinding While I was just looking for firing pin springs, I'll have to pick up a spring kit from Midway next time I place an order from them. Not meaning to change topics but I was just wondering how often you clean your CMMG bolt? I have a bunch of mags that I bring loaded to the range, about 700 rounds worth. I clean it after every trip but I'm thinking of picking up some more mags but if I can't shoot the extra rounds without a cleaning, there would be no point. |
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I have a bunch of mags that I bring loaded to the range, about 700 rounds worth. I clean it after every trip but I'm thinking of picking up some more mags but if I can't shoot the extra rounds without a cleaning, there would be no point. Largest 22 loadout I've gone through in a single range session, with no cleaning, and stopping only for ceasefires and to reload mags was 28 25rd cmmg first gen magazines and 6 30rd ciener mags, so 880 rounds. |
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Quoted: Largest 22 loadout I've gone through in a single range session, with no cleaning, and stopping only for ceasefires and to reload mags was 28 25rd cmmg first gen magazines and 6 30rd ciener mags, so 880 rounds. Quoted: Quoted: I have a bunch of mags that I bring loaded to the range, about 700 rounds worth. I clean it after every trip but I'm thinking of picking up some more mags but if I can't shoot the extra rounds without a cleaning, there would be no point. Largest 22 loadout I've gone through in a single range session, with no cleaning, and stopping only for ceasefires and to reload mags was 28 25rd cmmg first gen magazines and 6 30rd ciener mags, so 880 rounds. I hadn't though about using Ceiner mags. I have some with a kit that I never got around to using. I'll have to give them a try. Also I could pick up a redi-mag adapter and use the wife's S&W mags. (I take it that the redi-mag adapter goes in and out pretty easy?) That should get me over 1,000 rounds. Time to do a torture test video? Note to self, might as well get one of those American 180 drum adapters and save myself the mag changes.
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Also I could pick up a redi-mag adapter and use the wife's S&W mags. (I take it that the redi-mag adapter goes in and out pretty easy?) That should get me over 1,000 rounds. Time to do a torture test video? Note to self, might as well get one of those American 180 drum adapters and save myself the mag changes. The adapter does go in and out pretty easily, but you can use the S&W 15-22 mags even without the adapter - though they'll be a little sloppy front to back and won't activate the bolt hold-open without the redi-mag adapter installed. Drums would definitely be the way to go if you can get them running right... 275 rounds at a time 
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Quoted: The adapter does go in and out pretty easily, but you can use the S&W 15-22 mags even without the adapter - though they'll be a little sloppy front to back and won't activate the bolt hold-open without the redi-mag adapter installed. Drums would definitely be the way to go if you can get them running right... 275 rounds at a time Quoted: Quoted: Also I could pick up a redi-mag adapter and use the wife's S&W mags. (I take it that the redi-mag adapter goes in and out pretty easy?) That should get me over 1,000 rounds. Time to do a torture test video? Note to self, might as well get one of those American 180 drum adapters and save myself the mag changes. The adapter does go in and out pretty easily, but you can use the S&W 15-22 mags even without the adapter - though they'll be a little sloppy front to back and won't activate the bolt hold-open without the redi-mag adapter installed. Drums would definitely be the way to go if you can get them running right... 275 rounds at a time I don't really care about the bolt hold-open. I have a CMMG bolt hold open but I never tried it as EVO mags were no where to be found and I haven't gotten any of the new mags. I'll have to try the S&W mags without it and see what happens. I like the Black Dog drums the best. I've already got some American 180 drums, all I'd need is the adapter... well that and some more winders as they are a hassle to change.
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