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Posted: 1/25/2026 2:00:53 PM EDT
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How do yall safely torque a barrel nut to a receiver with a dedicated 22 chamber? Does this require clamping the barrel? I thought I could do it with this NcStar receiver block but the chamber won’t let the inner block seat all the way. Attached File |
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I’ve got just a little more pressure on it than what’s needed to hold it all in there. Attached File l |
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Originally Posted By neight: Bcm says 40-50#’s on the barrel nut but is that necessary? Was thinking I’d go 25 to 30 maybe Clamping the receiver works fine but the safest method to protect the index pin and corresponding notch in the upper is to clamp the barrel. I've done both though. 40-50 ft/lbs on a 22 is over kill. Shoot for 30-35 ft/lbs. That amount of torque shouldn't damage anything regardless of which method you choose. |
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Originally Posted By neight: Thanks. I went a hair over 35#’s. There is a small amount of travel in the bolt when I charge it. It’s on a lower with a KNS 1913 due Dad. So it’s not a buffer issue. Am I missing something behind the bolt? Recoil spring worn out? Pics? |
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Originally Posted By neight: Thanks. I went a hair over 35#'s. There is a small amount of travel in the bolt when I charge it. It's on a lower with a KNS 1913 due Dad. So it's not a buffer issue. Am I missing something behind the bolt? Usually a pressure plug on top of the buffer will solve the problem but thats not an option for you. Can the 1913 do dad be screwed in another turn ? If it can,this may solve your problem. If not, you'll need to make a shim of some sort to take up the gap. I'd try some thin rubber cut to fit or maybe a 3d printed TPU shim. |
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Originally Posted By shultz: Pretty common. It's tolerance stacking between the upper, lower and conversion bolt. It can and usually does cause cycling problems. That little movement occurs as the rd fires and robs a good bit of bolt energy causing all sorts of malfunctions. Usually a pressure plug on top of the buffer will solve the problem but thats not an option for you. Can the 1913 do dad be screwed in another turn ? If it can,this may solve your problem. If not, you'll need to make a shim of some sort to take up the gap. I'd try some thin rubber cut to fit or maybe a 3d printed TPU shim. Thank you. Definitely getting some feeding and extraction issues. I’ll try giving the 1913 plug a turn or two and cutting a shim out of something. Had to stop playing and fix dinner for some hungry kids before I can try all that. |
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I was able to get a few more turns on the plug, which took up most of it. It’s now only a couple thousandnths. I believe I can shim it with some shim stock. Still getting some feed and extraction issues but I’ll have to fuss with it tomorrow. Attached File |
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Originally Posted By neight: I was able to get a few more turns on the plug, which took up most of it. It's now only a couple thousandnths. I believe I can shim it with some shim stock. Still getting some feed and extraction issues but I'll have to fuss with it tomorrow. https://www.ar15.com/media/mediaFiles/244521/IMG_6808_jpeg-3701886.JPG looks good! How much wobble do the mags have in the mag well? if you can shift the feed angle of the bullet from nose up to more flat you need to shim this as well so the bullet nose is pointing at the chamber. A small piece of the fuzzy side from sticky back velcro placed in front or back of the mag well can often fix this. You can do the same on individual mags as well. The CMMG chamber adaptors/collars often have feed ramp burrs/sharp edges and or not so smooth feed ramps in general. breaking sharp edges and polishing the feed ramp helps. some hollow point ammo can also have feeding issues, however most feeding issues are related to mag position and feed ramp. take a look at the extractor. often there are sharp edges and or burrs that keep it from moving easily or cause a hang up and failure to control extract extracted case. you also want a claw edge that's nice and sharp, getting the most rim contact possible. I've had some that had a burr on the point of the claw that reduced rim contact by half... I also like to use a bore buddy extra power extractor spring especially when using an FRT. gives the extractor a better bite on the rim so it doesn't lose control of the case before hitting the ejector. Rough chamber can also be a cause for extraction issues. Buzzing the chamber with a bore brush attached to a drill will polish the chamber a bit. new 22cal bore brush, put some CLP on it, stick the brush in about an inch and let it rip for 30 seconds or so. I always make sure the extractor is squared away before taking this step. If you're careful, more so than using a chamber brush, a little flitz on a 22cal bore mop will do a better job. If you do this, you only want to do the part of the chamber that the case contacts! don't run the bore mop all the way in and polish the end of the chamber, lead and rifling 
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Thanks! I’ve been sitting on all these parts for a long time. I don’t know why I put it off, this thing is a hoot! Yeah these mags are very wobbly. So much so the feed angle looks like it’s swaying 5 to 7 degrees or so. I figured I’d start with them first. I’ve got clean CCI with the blue coating and some Norma hollow points. Both are sub sonic. Wasn’t able to shoot it enough to isolate one or the other but I think the Norma’s have had the most issues. Bore buddy has all sorts of parts but I don’t really know where to start. What does everybody suggest? The reliability combo? I’ve got a CMMG bolt and 17” barrel combo in a spikes 9mm receiver. Wish I went with a shorter barrel but figured the longer barrel would be the most reliable with sub sonic ammo. |
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Originally Posted By neight: Thanks! I've been sitting on all these parts for a long time. I don't know why I put it off, this thing is a hoot! Yeah these mags are very wobbly. So much so the feed angle looks like it's swaying 5 to 7 degrees or so. I figured I'd start with them first. I've got clean CCI with the blue coating and some Norma hollow points. Both are sub sonic. Wasn't able to shoot it enough to isolate one or the other but I think the Norma's have had the most issues. Bore buddy has all sorts of parts but I don't really know where to start. What does everybody suggest? The reliability combo? I've got a CMMG bolt and 17" barrel combo in a spikes 9mm receiver. Wish I went with a shorter barrel but figured the longer barrel would be the most reliable with sub sonic ammo. Fixing the mag wobble will go a long way to good feeding. Maybe your feed ramp needs a little de-burring and polishing as well. Same with the extraction issues, if you find the extractor binds or hangs up or has poor rim contact fix that before just throwing money at it. |
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Originally Posted By shultz: Bore buddy makes good stuff. I use a lot of their parts. Having said this, you most likely don't need any of them. The CMMG kits tend to run pretty well as is. Some, maybe your's need a little clean up of edges and polishing but that's it. I don't think any of the CMMG parts are "bad" and need immediate replacement. What I would do, as you break/ware out parts replace with Bore buddy. I do think the quality is better for things like springs, firing pins and extractors. One item I would highly recommend is either a CMMG dedicated 22lr solid polymer charging handle or the bore buddy charging handle insert. When, not IF a case gets stuck in the CH it can be a real PIA to get out! I use bore buddy bolt buffers as well, but again not really needed. Fixing the mag wobble will go a long way to good feeding. Maybe your feed ramp needs a little de-burring and polishing as well. Same with the extraction issues, if you find the extractor binds or hangs up or has poor rim contact fix that before just throwing money at it. I figured stabilizing or switching out the magazines would be a good place to start. Polishing the internals and checking the extractor would be a close second. I'll get the insert for the charging handle. What magazines are you using? I found I have a cmmg bolt hold open adapter Im sure I got on the ee. Id like to be able to use the bolt catch. Which makes the M&P magazines appealing if the fit up tighter. |
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I still use older CMMG and Black Dog machine mags. I have a bunch of both, they still work for me, even with an FRT. I just recently bought some arms unlimited 22 conversion mags that have worked fine so far, very limited testing due to recent weather. These were $10 ea for 15 or 25rd mags. I've never used one of the true bolt hold open set ups or the mags needed to trip one. As far as I know, the the newest cmmg mags, Kriss mags and of course M&P 22 mags work fine and give a mostly reliable, true LRBHO. Pretty sure the M&P mags need a magazine adapter for the lower, shim clipped on to the lower or added to the mag for better mag well fit and feeding angle. |
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Thanks. It does seem to feed better now it’s got some carbon in the system. I can’t understand why these gen 2 cmmg zines I have are so undersized. But they are. I will install the old BHO adapter I’ve got shortly and see if that doesn’t help the sway and feed angle issue the undersized mag causes. Looks like it might help square them in the mag well. Definitely want a couple more mags for when I intro this to the kids. Wondering if the Kriss ones are a better fit? The open cavity in the charging handle is a problem. Every so often a spent case bounces in there and causes ftf. I haven’t tried to really group it yet but she points very naturally and is pretty close to zero on factory setting. Already want to build another one with the Angstadt SD barrel. Over all about as much fun a gen Xer can have with his pants on! |
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All the mags have some wobble. How much depends on tolerance stacking between your lower and the mags. The wobble I have on my current set up, dosen't cause feeding issues so I leave it. I have in the past used lower/mag combos that had to be shimmed unless I really wanted to practice my malfunction clearing skills Get the insert, makes clearing malfunctions easier because the case can't end up trapped by the CH/bolt. Then again, once you get it feeding/extracting properly malfunctions are rare. I still get an occasional stove pipe. these are so random and again rare its very likely that particular case rim caused the problem not the gun... I've never even fondled a Kriss mag much less used one. I agree, I'm genX as well and really enjoy shooting 22lr guns. Just simple, cheap fun. Once you get your set up running good, consider an FRT. Takes some additional parts and tuning can be a PIA to get it running right but once you get there it nearly beats pants off fun 
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Definitely will get the CH fix and a pair of the Kriss magazines. The BHO assist actually prevents these CMMG’s from rocking back and forth quite a bit. I just slipped it in there and ran a few strings and seems to have eliminated most ftf. The spent case in the CH remains the biggest problem. Magazine fitment and the CH issue are probably all I need to fix to make it a real sewing machine. I don’t believe the plastic BHO adapter is a permanent fix as it’s pretty chinsey. But at least helped me isolate the mag issue. |
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Originally Posted By neight: Definitely will get the CH fix and a pair of the Kriss magazines. The BHO assist actually prevents these CMMG's from rocking back and forth quite a bit. I just slipped it in there and ran a few strings and seems to have eliminated most ftf. The spent case in the CH remains the biggest problem. Magazine fitment and the CH issue are probably all I need to fix to make it a real sewing machine. I don't believe the plastic BHO adapter is a permanent fix as it's pretty chinsey. But at least helped me isolate the mag issue. One other place is the extractor grove cut in the barrel. If it's not properly cut, it can keep the extractor claw from even grabbing the rim. It should be deep enough and have enough angle that it allows the claw to contact the rim and lock on. If either are not the case, the claw will be slightly held away from or just barely touching the case rim. When this happens sometimes the claw will grab the rim as the bolt/case move together, sometimes it doesn't... |
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I went thru my spares in the hopes of finding a good example of an extractor that will have issues. I found two edit: I should have said to begin with... these are brand new out of the package, not well used! What you're looking at left to right. Bore buddy power extractor, Black Dog machine extractor and last CMMG. Attached File Attached File I hope you can see the unevenness, burrs and even chipping on the black dog and CMMG. Neither of these would work well at holding onto the rim. On the other hand,the BB is square, nicely shaped and will positively hold as much rim as possible. Another view of the black dog. Attached File Cmmg Attached File Bore buddy Attached File The bore buddy is the only one I would install as is.... Either of the other two can be fixed with a little file work. Once the claw looks like the bore buddy, they should work just fine. |
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Originally Posted By neight: So shorter is ok, so long as the profile is crisp? Of the 3 examples, the CMMG is hands down the worst. The claw is also a touch longer than either of the other two and would still clean up without losing any length. |
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I failed to mention another potential trouble spot... On the CMMG extractor. See how short the relief cut is that allows the extractor to pivot inwards without hitting the edge of the bolt too soon compared to the other two? Yeah, that can prevent the extractor from fully grabbing the case rim because it hits the edge of the bolt before gripping the rim properly. |
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Thanks I'll pull it out and bench test it tomorrow. I do think the main issue is the open CH. Magazine fitment a second. It'll run a full magazine with no issues and the next mag is stoppages every 4th or 5th round. I might try some standard velocity for science. But all I really want to shoot is subs. |
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Originally Posted By neight: Thanks I'll pull it out and bench test it tomorrow. I do think the main issue is the open CH. Magazine fitment a second. It'll run a full magazine with no issues and the next mag is stoppages every 4th or 5th round. I might try some standard velocity for science. But all I really want to shoot is subs. The root cause is the case coming off the bolt face before it can hit the ejector. or because of a funky claw shape, when the case does hit the ejector the case dosen't release clean and flips up instead of out. |
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I would try some high velocity 22lr You said you were using sub sonic stuff. Most standard 22lr bolts will be sprung to the HV stuff. If the combo of bolt weight and spring is to high for the weaker sub sonic stuff you will have fte and ftf Get it running with the HV stuff then tune it down to the sub sonic stuff. Using sub sonic stuff will require a different recoil spring. Bore Buddy has them. |
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Originally Posted By shultz: Nah, the open charging handle just makes the malfunction worse when the case flips into it. The root cause is the case coming off the bolt face before it can hit the ejector. or because of a funky claw shape, when the case does hit the ejector the case dosen't release clean and flips up instead of out. Ah, it needs to be tuned then. Thank you. Is it consumable? Guess I'll get another for a spare. |
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Originally Posted By neight: Ah, it needs to be tuned then. Thank you. Is it consumable? Guess I'll get another for a spare. No, one and done. What it prevents by filling the open channel... I had a case flip up into the CH channel, then get wedged in that little hole at the the front the recoil spring tube on the top of the bolt. It then slammed back into the front of the CH as the bolt closed or tried too... I had to hold the bolt open with my left thumb since pulling the bolt back using the CH just jammed the whole mess together. Once the bolt was held back a bit I was able to dig the case out with a small blade screw driver. PIA! Trying some HV ammo for breakin isn't a bad idea. With your 17" barrel there is more than enough dwell time with SV ammo to provide the ummph needed to cycle the bolt. Most, if not all SV should work fine in your set up. If you had a shorty, then yeah a recoil spring change would likely be in order. |
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