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Posted: 7/30/2014 5:24:29 AM EDT
I figured I would ask as I go to receive any advice... from what I have read, i'm going to need it
I want to get a rdias running with a complete spikes tactical st-22 4.5" suppressed upper (therefore spikes bcg, barrel, collar assembly and regular charging handle). I have purchased and am waiting on CMMG's auto sear trip and anti bounce weight. I have no idea if they are compatible, but will soon find out. Also have metal feed lipped black dog mag with bolt hold open follower. Not opposed to ditching spikes bolt or any other parts, but want to identify what I need first. thank you for any advise and will update this when problems present themselves... which I expect |
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22 uppers with a trip will work with M16 lowers and RDIAS, they will not work with RLL.
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CMMG's weight is ridged for use with their forward assist adapter, and has a 'nub' at the back in order to be engaged by the forward assist when fully in battery. You'll either need to notch your spike's frame to pass the nub, or grind the nub off to use with your un-notched spike's frame.
Might need to do some profiling to the underside of the spike's bolt to use with the cmmg sear trip, or it might fit and work OK without alterations. |
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Quoted:
CMMG's weight is ridged for use with their forward assist adapter, and has a 'nub' at the back in order to be engaged by the forward assist when fully in battery. You'll either need to notch your spike's frame to pass the nub, or grind the nub off to use with your un-notched spike's frame. Might need to do some profiling to the underside of the spike's bolt to use with the cmmg sear trip, or it might fit and work OK without alterations. View Quote you are exactly right now that i have the anti-bounce weight is in hand. should be anti-bounce weight slide freely all the way from the front (where the firing pin is) to the back (where the nub u say to grind would go)? The underside of the spikes bolt WILL have to have material removed in order for this to happen. The nub will also need to be ground. Thank you! |
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The debounce weight needs to slide up under a lip on the underside of the return spring guide. It fits right behind the back of the bolt, and should have only about 1/16" of travel. It's meant to slide back and forth with the bolt, but have a little teensy delay like a dead-blow hammer to prevent the bolt from bouncing back out of battery after hitting home on its forward stroke. Hence, debounce, or anti-bounce weight.
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First, thank you for any advise. Your time it is MUCH appreciated
Update: removed material out of the spikes bolt carrier to accept the nub of the cmmg anti-bounce weight, it now interfaces. It cycles better with a full mag and never functions in auto with the <5 rounds in a mag (mag is black dog with steel feed lips). I'm getting strings of 6 at most but predominantly less sometimes the 2nd round wont even fire. Semi functions perfect. There are no ejection, stovepipes, or feed issues. It always stops the string with a light primer strike and the hammer has fallen. Ammo used: Federal and Winchester bulk pack. What do I need to get now? A 'lakeside spring' or similar and start chopping and testing? truth be told, I don't know if I need more spring tension or less Don't they make a improvised firing pin? Can I add mass to the anti bolt-bounce weight? Do I need to preform the gorilla ball detent mod? http://www.ar15.com/forums/t_6_20/199744_.html&page=4 This 'reliability kit'? http://www.taccom3g.com/22RF_RELIABILITY_KIT.html If a specific product, please link. Thanks again |
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Quoted:
First, thank you for any advise. Your time it is MUCH appreciated Update: removed material out of the spikes bolt carrier to accept the nub of the cmmg anti-bounce weight, it now interfaces. It cycles better with a full mag and never functions in auto with the <5 rounds in a mag (mag is black dog with steel feed lips). I'm getting strings of 6 at most but predominantly less sometimes the 2nd round wont even fire. Semi functions perfect. There are no ejection, stovepipes, or feed issues. It always stops the string with a light primer strike and the hammer has fallen. Ammo used: Federal and Winchester bulk pack. What do I need to get now? A 'lakeside spring' or similar and start chopping and testing? truth be told, I don't know if I need more spring tension or less Don't they make a improvised firing pin? Can I add mass to the anti bolt-bounce weight? Do I need to preform the gorilla ball detent mod? http://www.ar15.com/forums/t_6_20/199744_.html&page=4 This 'reliability kit'? http://www.taccom3g.com/22RF_RELIABILITY_KIT.html If a specific product, please link. Thanks again View Quote I know a thing or two about Spike's Tactical ST-22 bolts, so I'll share some lessons I've learned. A) Action (Lakeside) Springs are touch and go, you might get lucky - or you might not. I've tried old, new, long, and short, and frankly I haven't had much luck swapping them. B) Detent mod is touch and go, but it seems to help if you can fit in a long (~1/4") spring. Buy a 3/16" ball bearing, 1/8" does not like to ride along the rail and tends to go flying when you try to work it in. C) Finding 1/8" OD springs is surprisingly tough. For reference, ball point pens are 3/16" and look like a St. Bernard trying to fit through the cat door. I think a Century Springs C-570 may be the ticket. I haven't bought any, so it might not. I would recommend you do NOT buy a full TACCOM reliability kit if you have a Spike's Gen 1 22LR BCG for two main reasons. 1) The firing pin cut is in the wrong location for Spike's Gen 1 bolts. It will work in Ceiner style Gen 2 kits. The ST firing pin is a proprietary design, so for it to work, you'll have to cut a spring pin/retaining pin channel. 2) The higher power recoil spring jams on a ST bolt, you'll need to chamfer the bolt tail for the action spring. Otherwise, the bolt slams shut on the guide rod and won't cycle. I do recommend the pressure plug, that's a great upgrade (and very affordable). Is your extractor bad enough you need a new one? It doesn't sound like it. My ST bolts always ejected live rounds well. Items to buy/parting thoughts: 1) The McFadden loader Tim sells is *top notch*. It is worth every penny, and then some. But it and a pressure plug are all I would buy from him if you want to rock and roll - even his bolt body is not milled for F/A use. 2) Have you filed on your hammer hook to ensure it doesn't drop when the trip moves forward? That little dip can rob your hammer of critical energy, IIRC the old thread discussions here correctly. 3) Have you tried any different hammer springs? 4) How tight are your rails? Are they aligned? They can bend with removing and reinstalling the collar. ETA: 5) The CMMG Anti-Jam charging handle may or may not be helpful. I have one ST bolt that has to have it, and the other doesn't care what non-GasBuster handle I use. |
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Stay away from the CMMG trip.
It is out of spec and and will cause timing issue with RDIAS. Get a ciener trip. Fair warning, dont buy the CMMG trip. |
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will spend more time tinkering this weekend, but already got the cmmg trip and bounce weight. seems to trip the dias and fire short strings of rounds but stopping on light primer strikes with the hammer fallen.
Ordered Taccom's enhanced firing pin and spring and had a discussion with Tim. He states I need to do 3 things: Increase the bolt spring tension (stop the bounce), slow the hammer down, and enhance the firing pin to strike the rim better. My anticipated course of action will be to 1) replace the bolt spring, I imagine that will increase the tension to help alleviate bounce. 2) see if I can bend the hammer spring legs approx. 15 degrees to slow the hammer. I don't need a weaker hammer spring since i'm getting light strikes to begin with, but we'll see. I'll probably do this last. 3) new firing pin which will hopefully work with the spikes bolt (I think I have a gen2, honestly don't know how to tell the difference). I can also file my existing firing pin to have less surface contact, thus increasing the impact where it does contact the rim, but hopefully the new pin will work. I'll maybe try to alter the trip to delay the timing it if none of this works, either by bending it or building it up. if the bolt would just close, and stay closed before the hammer falling, I believe it would work 100% eta: thanks for your insight so far guys. it is appreciated |
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Go to the cmmg forum industry on this forum.
Search for the pics l posted showing how far out of spec the trip is. I cant understand why they continue to sell it. Don't bother bending it. Its too far off. You can build it up. I did. In fact I still have that trip and will gladly trade you something gun related for it. When all said and done .22 is kinda not worth it in a m16. I gave up on it because the rate of fire is just too high. The first person that invents a slow fire bolt will be rich. 1500 down to 800. Until that time .22 is not for me. Lage did it for his .22 kits for m11. Someday someone will do it for the m16. |
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Taccom firing pin (with some file work) and taccom bolt spring installed. Did not resolve problems. So I Installed weaker powered JP red trigger and hammer springs and was functioning marginally better, enough to notice that this helped, so I put a 20deg bend on each leg of the hammer spring to lighten further and that's where i'm at now. truthfully, I don't know why that helped, but it did. I guess it 'slowed down the hammer' or something? Should I bend the legs more?
It runs strings somewhat consistently but has a few f2f per mag. Same issue: it stops with a f2f, hammer has fallen, light primer strike. Where do I go from here? Gorrilla ball detent mod? That's going to be a tuff mod for me, but i'll try if required. Please advise if there is something I can try before that. eta: sear is tripping correctly, I don't think I need to adjust that. When manually cycling in auto, holding the trigger, it drops the hammer almost exactly when the bolt is fully closed. When manually cycling, the extractor will keep it from closing, and when pushing the forward assist, it trips after the extractor gets out of the way. I imagine that's as good as it gets timing wise, but color me ignorant about these things. |
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Did you say that you tried a extra power bolt spring like a lakeside?
Lakeside had sold the entire kit with everything to fine tune the setup. I think they are out of business or changed their business and good luck finding a kit. After I got mine going the best I could, I gave up on it and found it to be a waste because it was so fast. 25 rounds in a blink of a eye. |
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Quoted:
Did you say that you tried a extra power bolt spring like a lakeside? View Quote I purchased and installed this spring: http://www.taccom3g.com/22RF_HP_RECOIL_SPRING.html and this firing pin: http://www.taccom3g.com/ENHANCED_22RF_FIRING_PIN.html So now, I guess I need to get this or make one: http://www.taccom3g.com/22INSERT_PRESSURE_PLUG.html Is it's sole purpose to just put pressure on the rear of the 22 bolt carrier? I should be able to fashion one up. thank you both for your advice, but short of the pressure plug and playing with the timing, is that all I can do? Should I bend the cmmg trip tab forward or backwards slightly (hoping not to break it) to play with the timing? I realize if bent to much, it will pass over the sear without tripping. Is there any way to differentiate timing (adjusting trip) from bolt bounce (the need for the ball detent mod)? edit: I don't have access to a high speed video camera |
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FWIW ... I started tinkering with .22 conversion kits for my M16 back in the mid-'90s, when the only FA option was the Ciener kit. Tried, and tried, and tried, and tried ... kits, dedicated uppers, different magazines, different ammo ... but I never did get it to run reliably in full-auto. Usually worked just fine in semi, but FA = No Way.
The problem is inherent in the .22 rimfire cartridge itself: First, it runs very dirty (lots of unburned powder being dumped in the action/chamber) and second, it just does not have enough power to keep running. A machine gun is, in many ways, less of a firearm and more of a machine for rapidly emptying magazines. We speak of how well other firearms shoot; with MGs, the question is how well they run. Weak ammo makes that difficult; so does dirty ammo. Combine the two factors, and the deck is stacked against you. A much higher rate-of-fire does help overcome this ... but at the same time, that gets it dirtier faster. If you get a full-auto AR .22 rimfire conversion running right -- and if you persist, and the moon is in the correct phase, and you have burn the proper offerings to the FA gods -- the odds are strong it will only run for a couple of mags before you need to strip it down and detail-clean it. Because with rimfire's unburned powder, you quickly build up enough crap that it keeps it from continuing to run. Also note: One of the changes you almost certainly will have to make is to go with a weaker hammer spring, because of the round's lesser strength. But that same weak hammer spring will make it potentially dangerous to run that lower in any other caliber, because with centerfire calibers, a weak hammer spring allows the hammer to hit the disconnector way too hard -- and that is a recipe for egging out the hammer and trigger pin holes in your receiver. Bottom line: Every time you switch from your .22RF kit to centerfire, you must also remove the fire-control group and replace the light hammer spring with a standard or stronger one. That means your conversion is no longer "plug-and-play," which to me defeats the purpose of having an M16, the Barbie Doll of machine guns. I have long since decided that the only way to shoot rimfire in an MG is with an open-bolt, because then, there are no hammer issues. The only variable is whether the round has enough oomph to push the bolt back to the sear. And open-bolt designs also tend to be more forgiving when running dirty. Unfortunately, there is no commonly available open-bolt fire-control kit for ARs. That's why the only MG I run in .22RF is my Vector Uzi. And it runs very, very reliably, and at a very low ROF now that I had Richard at BWE tune it and make his slow-fire mods. Sorry for the "negative vibes." Just call me the Kaliber Konversion Kurmudgeon. |
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Quoted:
thank you both for your advice, but short of the pressure plug and playing with the timing, is that all I can do? Should I bend the cmmg trip tab forward or backwards slightly (hoping not to break it) to play with the timing? I realize if bent to much, it will pass over the sear without tripping. edit: I don't have access to a high speed video camera View Quote Without knowing exactly what's going on, you don't know what to adjust, or which way, and/or which combination of factors is causing you difficulty. You can try many things, which I will detail in a moment, but without data directing your efforts, it's all being systematical in a blind search. Don't bend the trip. If you need to advance the timing you can build up the trip face with metal tape or glue or putty. If you need to retard the timing, well, you can remove a bit of material from the front of the trip and/or from the back of the auto sear. When tinkering, you modify the cheapest part you can, or failing that, the one you have ready spares for. You can see if your problem is early timing easily enough by building up layers of tape or whatever a few thousandths of an inch at a time on the trip and seeing if that helps, up until the thing just stops running. Maybe lay out a graph of how it seems to respond as each layer is added and some test shots are fired, and see if there's an obvious sweet spot to try. If that's no good, you could try taking about half the thickness of the trip off the front of the trip, and half the thickness of the auto sear off the back, which should make your timing way, way late. Then start the tape buildup again, to give you data from way late timing (no tape/buildup either side) through to way early timing (built up enough it's failing to fire every time). There may in fact be multiple sweet spots, depending on the bolt bounce and frame movement your kit is experiencing, and its behavior may change depending on how firmly or loosely you hold it. Failure to firmly shoulder a 22 conversion is pretty much like limp-wristing a semi auto pistol, and is a problem all itself. xm15e2s refers to his measurements showing the cmmg trip to not have the same timing as a GI M16 carrier (and the Atchisson/Ciener style trip) - which is correct, but not necessarily probitive, as the 22LR conversion bolt may not use the same timing parameters as a full-spring buffered rifle action. I've never gotten any of my 22 conversions running truly 100%, but have gotten them really, really close - to where I blame the occasional dud on the variability of bulk pack 22 ammo rather than the conversion - though it's possible the conversion was in fact to blame in those cases. However, I have the luxury of dedicating a lower to my 22 setup, even though I do run a more-or-less standard M16 FCG with full power hammer spring in that lower, so it's theoretically fine to swap on other uppers, and I have done so with no problems on multiple occasions after firing up all the 22 we'd brought along. My kit is a CMMG Evolution with TACCOM reliability kit (recoil spring, extractor and firing pin) installed. I have both a locking collar and the taccom pressure plug, and it works best with the collar unlocked and the pressure plug installed. |
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What needs to be addressed in the 22 conversion is what is its major design flaw.
Its too fast and that causes all the problems. I wish I had machine skills. I thought of a way where the trip was attached to a spring and the bolt had a secondary trip on it. When the bolt was forced back it pushes the trip back and the trip is caught by a secondary sear. When the bolt goes forward the secondary trip hits the secondary sear and the main trip flies forward. The end result is that the hammer is deyaled by maybe 20% or more. This corrects for bolt bounce and any timing issues and lowers the rate of fire by a bunch. The entire design is added to the 22 conversion and nothing is added to the host rifle. The idea is in my mind and on scratch paper. I just don't have the skills to make it happen. The design basically makes the trip into a very low power secondary hammer that hits the trip on the auto sear. The extra distance the trip has to travel adds a short delay in the firing process. |
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Wanted to let all that helped know I have it running and I’m in love! Screw 5.56, 22lr is where it’s at! This was the goal of the game when I started this entire dias process a year ago, knowing I can’t afford lots of 5.56, so I’m very happy. Thank you 22lr gods!!!
A friend had an even longer, more powerful spring than the Taccom one I purchased, so I’m not sure who the manufacturer of it is, but it’s a good 2” longer. At first I thought it was going to be too powerful and anticipated clipping it, but it ejects, locks the hammer back, feeds and functions, from what I can tell so far 100%!!! For full function, it required the removal of the bolt bounce weight so the only mods are an enhanced firing pin, (way) stronger bolt spring, weak hammer springs (with additional 15-20degree bend on the legs), and the auto trip. I wanted the forward assist/bolt bounce weight in it but it won’t function correctly when installed, so it is now spare parts. Who knew? I am now fumbling with a BHOA but it’s proving to be a PITA and not really a big deal if it doesn’t work. It seems, when installed, the bolt won’t close all the way. Seems to stay open approx. 1/16” and messes up when feeding. Again, if I never get the BHOA working, not a big deal, but if there is info out there, I’m all ears. Thanks again all that helped! |
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