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[ARCHIVED THREAD] - 22lr buffer spacer "pressure plug" (Page 1 of 3)
Posted: 4/9/2019 7:11:16 PM EDT
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I usually hang out at Rimfire Central for all things 22LR related, but I recently got a CMMG conversion kit and ran across the (now unavailable) Taccom buffer plug to tension up the conversion kit style 22lr bolt assembly. I made a few improvements to the design for quick insertion without having to depress the buffer pin -- align the slot and push in, and then rotate 1/4 turn to seat in the slot. The slot can also be used to turn the spacer with a coin, screwdriver, key, etc. 
I have 5 extra 3D printed prototypes that I'm going to be sending out for testing to the first few people who want them. I think I have 2/5 spoken for on RFC. My only condition is that you pay the postage and my material cost ($7 total) and that you post up any suggestions, improvements, and other feedback. I'm also interested in any accuracy improvements, the spacer keeps the CMMG assembly much more firmly in place when cycling manually. It seems takes a lot of the slop out of the chamber adapter, and you have to pull hard enough on the charging handle to counteract the buffer spring in order to move the assembly now. I'm planning to test groups with and without to see if there is a noticeable effect on accuracy as well. I'm thinking that there will be some effect, since the adapter should be much more firmly and consistently seated for each shot. PM me if interested! |
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So I got the material pricing nailed down, and it looks like I could make and offer machined versions made from delrin at $12 if there is sufficient interest. I'm going to ship off the prototypes to the 4 people who messaged me since yesterday evening this afternoon.
Let me know if you'd be interested in a machined delrin part -- this will help me judge whether I could make them without losing a ton of money. If 10 or so people want one, I'll make some. |
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Quoted:
I just cut a length of 3/4 PVC that slips into the buffer tube. But this is a nice part that I'd pay for if you made some. Seems odd that TACCOM just totally bailed from the market when there appears to still be demand for their parts. I'm just a hobbyist, so I don't mind making things in smallish runs and holding some inventory if it's something I "need" as well! |
| That looks awesome! |
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Quoted:
So I got the material pricing nailed down, and it looks like I could make and offer machined versions made from delrin at $12 if there is sufficient interest. I'm going to ship off the prototypes to the 4 people who messaged me since yesterday evening this afternoon. Let me know if you'd be interested in a machined delrin part -- this will help me judge whether I could make them without losing a ton of money. If 10 or so people want one, I'll make some. Actually, I know of an organization that might buy a bunch of them if they work well. I'll shoot you a PM. Dave |
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Also, it would be interesting if you would consider making a drop in insert for the cavity of the charging handle. If you look at the design of the CMMG 22lr charging handle this will give you an idea of the concept. This is supposed to further reduce malfunctions while using a 22lr bolt. This would allow people to use their standard charging handle, ambi controls and such. As a package deal, it would be much more appealing....... at least I think so. The CMMG handle is all plastic and has a milspec latch. Gross. |
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Quoted:
Also, it would be interesting if you would consider making a drop in insert for the cavity of the charging handle. If you look at the design of the CMMG 22lr charging handle this will give you an idea of the concept. This is supposed to further reduce malfunctions while using a 22lr bolt. This would allow people to use their standard charging handle, ambi controls and such. As a package deal, it would be much more appealing....... at least I think so. The CMMG handle is all plastic and has a milspec latch. Gross. |
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Quoted:
If you can make these and ship them for around that price point I would buy a couple. Actually, I know of an organization that might buy a bunch of them if they work well. I'll shoot you a PM. Dave Quoted:
Quoted:
So I got the material pricing nailed down, and it looks like I could make and offer machined versions made from delrin at $12 if there is sufficient interest. I'm going to ship off the prototypes to the 4 people who messaged me since yesterday evening this afternoon. Let me know if you'd be interested in a machined delrin part -- this will help me judge whether I could make them without losing a ton of money. If 10 or so people want one, I'll make some. Actually, I know of an organization that might buy a bunch of them if they work well. I'll shoot you a PM. Dave Another Dave |
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Quoted:
Be careful not to sell/advertise without the proper ok's on this forum. They'll shut you down quick. |
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Quoted:
I usually hang out at Rimfire Central for all things 22LR related, but I recently got a CMMG conversion kit and ran across the (now unavailable) Taccom buffer plug to tension up the conversion kit style 22lr bolt assembly. I made a few improvements to the design for quick insertion without having to depress the buffer pin -- align the slot and push in, and then rotate 1/4 turn to seat in the slot. The slot can also be used to turn the spacer with a coin, screwdriver, key, etc. https://i.ibb.co/LnsTcMW/buffer-plug-1.jpg I have 5 extra 3D printed prototypes that I'm going to be sending out for testing to the first few people who want them. I think I have 2/5 spoken for on RFC. My only condition is that you pay the postage and my material cost ($7 total) and that you post up any suggestions, improvements, and other feedback. I'm also interested in any accuracy improvements, the spacer keeps the CMMG assembly much more firmly in place when cycling manually. It seems takes a lot of the slop out of the chamber adapter, and you have to pull hard enough on the charging handle to counteract the buffer spring in order to move the assembly now. I'm planning to test groups with and without to see if there is a noticeable effect on accuracy as well. I'm thinking that there will be some effect, since the adapter should be much more firmly and consistently seated for each shot. PM me if interested! |
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That I don't know. I only have ever had experience with carbine buffers and tubes. I'd think that the pin would still stop the rifle buffer from coming forward enough to contact the back of the 22 lr group. This issues is why I put the slot cutout for the pin. |
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Quoted: Could you also turn down the diameter on one end of the plug so that it would partially fit into the buffer spring and eliminate the need for a buffer? As long as it was slightly smaller than the inner diameter of the spring it would still let you rotate it into position. Quoted: Could you also turn down the diameter on one end of the plug so that it would partially fit into the buffer spring and eliminate the need for a buffer? As long as it was slightly smaller than the inner diameter of the spring it would still let you rotate it into position. Quoted: Or just take out the retaining pin? Someday if I build a dedicated 22lr upper, I will may create a custom buffer that functions as a spacer as well. Until then, This part has been working wonderfully! |
I just got back from running a hundred or so rounds of several different types (mostly very cheap ammo) through the rifle with the buffer spacer, and it functioned flawlessly, save for one Wolf extra match casing that stovepiped. A variety of bulk pack ammo shot smoothly and fairly accurately. I forgot my targets, so with some trash and a sharpie I improvised:
L to R: Armscore, Federal 325 bulk, Winchester 555 Bulk, Wolf Extra Match 
And Aguila supermaximum was like a shotqun, POA top right dot: 
As a comparison, here is two of the bulk pack ammo types through an old marlin 780: Armscor: 
Winchester 555: 
Overall, I'm impressed. It shoots a bit low in my 223 sighted scope, but I have the BDC Style reticle, so it's easy to shoot without changing zero. |
Just received the prototype I was sent today. I'll be at the range tomorrow for my first run with it. Even though this is just 3D printed plastic I'm already very impressed. The final delrin product will be worth the wait folks. I appreciate the opportunity to be able to test a prototype. Will post my range trip report tomorrow evening, promise. I'm already finding it simple to just thumb pressure it in, twist and line up the notch. A quarter or nickel would really work well if you want to minimize your thumb getting dirty. I happen to have a key I keep on my ring that I cut along time ago to work with the slot in the Magpul screws on their flip sights, AFG's etc........ so I could always in the field remove or reposition them. It happens to work perfect for this application as well.
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Just got back from the range. Works great. The only complaint I could have is that the plug actually sits a bit too far out and makes closing of the upper a bit difficult without pushing the plug back into the tube a bit. Being printed out of 3d plastic I wanted to be careful with the proto instead of just slamming it closed like I normally would on the TACCOM/Velocity plugs. I'm curious to see with the Delrin revision of this if it will be the same case or not since that is tougher material. This plug will be very useful to pair with a Ciener/CMMG style .22 conversion or dedicated upper setup. Sorry didn't think to take pictures or video at the range today. I snapped this when I just got back. 
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Quoted:
Just got back from the range. Works great. The only complaint I could have is that the plug actually sits a bit too far out and makes closing of the upper a bit difficult without pushing the plug back into the tube a bit. Being printed out of 3d plastic I wanted to be careful with the proto instead of just slamming it closed like I normally would on the TACCOM/Velocity plugs. I'm curious to see with the Delrin revision of this if it will be the same case or not since that is tougher material. This plug will be very useful to pair with a Ciener/CMMG style .22 conversion or dedicated upper setup. |
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Couldn't you use the 9mm buffer extensions for standard 556 buffers? Quoted: Yes, or quarters, or nothing, but this gets around pulling the buffer retaining pin. My main criteria (roughly in order of importance) were: 1.) Apply pressure to the back of the 22lr bolt group (obviously) 2.) NOT create a need to remove anything from the rifle assembly (i.e. replacing the buffer, removing the pin, etc. I am scatterbrained and likely to lose things if they are removed for any length of time) 3.) No pressing on the pin required to insert or remove (read: one handed installation) 4.) Simple design that is easy to build, without any complex machining operations required (can build on manual equipment if necessary) I'm sure there were a few other things that led to this design as well. Thank you to those of you who made suggestions! |
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It just dawned on me that I have a CMMG and an old Atchisson/Ciener and they are different at the back. The relief cut on the CMMG clears the top better and hits the chamfered area. Sorry I should have clarified that earlier. Heres some pictures. https://i.imgur.com/TxV5Wv5m.jpghttps://i.imgur.com/sF0UPuUm.jpghttps://i.imgur.com/n2DVTu4m.jpg MHO, YMMV, etc. |
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Quoted: My 2010 CMMG Stainless conversion has the old "full circle" back plate of the Atchisson Mk II patent (U.S. 4,169,329). I believe that CMMG may have changed their back plate to have the slant cut at the bottom at or about the same time that they came out with their chamber insert lock .22 conversion (U.S. 8,726,560). The CMMG '560 patent and U.S. 4,617,749 (the Air Force .22 conversion) present two of a number of alternative approaches to addressing potential fore/aft movement of .22 conversions in AR-15/M16 pattern firearms that have been made over the last 40+ years. MHO, YMMV, etc. The plugs (I stuff 2 in there) do keep feed and extraction issues from occurring. The conversion would shift slightly back and forth causing issues. With the plugs no issues. |
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Just submitted my pre-order. I'm looking forward to it! ETA thanks, @Renaissancemann . I fully realize there are a couple "budget" options, but I appreciate a guy looking to innovate, takes feedback and has the desire to execute. Money well spent in my book.  |
[ARCHIVED THREAD] - 22lr buffer spacer "pressure plug" (Page 1 of 3)
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