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Posted: 9/7/2025 6:50:19 PM EDT
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I'm in the market for a dedicated 22 LR upper that I can put on an arbitrary (low pocket) lower with an FRT that will run with as few headaches as possible. I think (but am not sure) the CMMG Banshee Mk4 (9") or BB AR22 (12.1") are my best(?) upper options? Are there others? I have AR lowers galore (all with low pockets), so I'd like to use one of those, if I can. Are there reasons specific to running an FRT that I should go with a particular lower? Is there a particular FRT that is easier to get running/more reliable than the others? I'm not currently committed to any brand or product. I'm in search of the most reliable/least finicky setup. Advice born from experience is greatly appreciated. |
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Quite simply, they are not quick and easy, or pre set up to get running. I have a thread here about trying to get mine to run. It seems to work at the moment. Good luck! I'll help if I can. |
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Quoted: Welcome to the world of trying to get a 22lr to run with a FRT. Apparently it is like playing the lottery. If you win the lottery, your gun works/runs. If you are like the rest of us, nothing you do can get it to work. Me included. All I can say is good luck. it's rather easy, I've built half dozen AR22s with Bore Buddy kits & Super Safeties, and they all run flawlessly |
| Mine worked great with the Gen 1 weight I got from Grey Market Research after it broke they sent me a replacement same pins and weight but redesigned to reduce failures now my SS won't run at all. Thinking of trying a different weight see if I can get it to run. Like others have said you could buy the best parts it might run it might not and you are going to have to play with it. |
| CMMG .22 LR conversion kits and dedicated uppers are designed to work with standard AR15 lowers, including those with low pockets. For CMMG DISSENT or Br4 platforms, you may need specific adapters (like a side charger adapter and a spacer) to ensure proper fit and reliable cycling. |
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Quoted: My CMMG .22 upper, with BoreBuddy weights, adjustable trip, and that BB plug thing that fits in front of the buffer works fine on a Spikes lower with RB 15L3 and Black Dog mags. In fact, it is fun as hell. Aside from the weights, did you do any fiddling or tuning? |
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Although BoreBuddy sells replacement springs for the .22 bolt carrier group, I am using the original springs which came with the CMMG Banshee .22 upper. So the only fiddling I've done is add the BB weights (these have inserts that you can use to adjust the amount of weight. I am using the heaviest combination.) as I said above, I am also using that plug thing BB sells to help keep the carrier pushed forward with less play). I should have also mentioned I am using a Silencerco Sparrow and have not tried using the upper without a suppressor so don't know if that makes a difference in reliability. Finally, I am using CCI 45 grain ammunition that says "for suppressor use" or something like that on the box. (The ammo is in my garage and I don't recall exactly what the label says, but its the 45 grain CCI) Next time I go to the range I will try to remember to try this combo without the suppressor and without the plug and report back Oh, I did have to use the adjustable trip sold by BB. The non-adjustble trip I had would not engage the lever on the RB 15L3 |
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Quoted: Next time I go to the range I will try to remember to try this combo without the suppressor and without the plug and report back. I would leave the plug in, as you may induce a bolt bounce failure without it. I use a cork in place of the plug, it just takes a little more finessing to get the receiver closed. You may need a different ammo without the can. If you have different brands, try them out too. Keep us posted. |
| Just a follow up on my previous posts. Took my .22 Banshee out again and this time tried it without suppressor. It did seem to run better with the Silencerco Sparrow, although I only had a couple of stoppages without the suppressor. As stated earlier, mine seems to really like the CCI 45 grain ammo. |
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So I'm finally putting one of these together with a SS and BB's SS trip kit. No live fire yet. Semi function checks fine. In FRT mode, I've got the reward set screw out just far enough for a consistent forced reset. However, my hammer is dropping on the return with about a 0.070" gap still between the bolt face and the collar. I'm a little worried about OOB detonation. As far as I can tell, the trip has no means to delay forward motion of the lever, only to advance it (by filing off the rear shelf and adjusting the steel bar according to the guide), which would make my problem worse (unless I misunderstood something). Is this something others have seen? Am I right to to fear that big of a gap? |
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Quoted: So I'm finally putting one of these together with a SS and BB's SS trip kit. No live fire yet. Semi function checks fine. In FRT mode, I've got the reward set screw out just far enough for a consistent forced reset. However, my hammer is dropping on the return with about a 0.070" gap still between the bolt face and the collar. I'm a little worried about OOB detonation. As far as I can tell, the trip has no means to delay forward motion of the lever, only to advance it (by filing off the rear shelf and adjusting the steel bar according to the guide), which would make my problem worse (unless I misunderstood something). Is this something others have seen? Am I right to to fear that big of a gap? Edit: I mentioned full auto and tweaking the trip but failed to state i have not tweaked the trip on my BB SS adjustable trip. As you say, it's only adjustable for reset, not trip without adding/removing material on the trip surface. Bottom line is .070 should work just fine. |
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Quoted: Edit: I mentioned full auto and tweaking the trip but failed to state i have not tweaked the trip on my BB SS adjustable trip. As you say, it's only adjustable for reset, not trip without adding/removing material on the trip surface. Bottom line is .070 should work just fine. Good to know. I was under the impression that it was adjustable for trip. I almost bought both types for the SS and ‘16. Both have required trip adjustments. |
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Quoted: ... I was under the impression that it was adjustable for trip. ... The BB SS trip kit is adjustable for the rearward reset with a set screw. (See the "Super Safety and Atrius Selektor" section in the guide.) Technically, the BB SS trip kit is also "adjustable" for the return forward as well, but it requires removing metal from either rear of the block (to advance) or (I'm guessing) the steel bar just forward of the screw (to delay). Are you aware of a more easily tuned alternative product we should consider? |
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Quoted: The BB SS trip kit is adjustable for the rearward reset with a set screw. (See the "Super Safety and Atrius Selektor" section in the guide.) Technically, the BB SS trip kit is also "adjustable" for the return forward as well, but it requires removing metal from either rear of the block (to advance) or (I'm guessing) the steel bar just forward of the screw (to delay). Are you aware of a more easily tuned alternative product we should consider? I am not. I’m using a fixed metal SS slide from supersafetyshop.com and a CMMG sear trip in the ‘16. The SS part has no problems with resetting and the ‘16 has a sear that’s reset without the trip. I have had to “adjust” the CMMG part with concussive persuasion. I may have to add material to the sled to advance the timing when the bolt comes home. It’s on the edge of not releasing the trigger when manually cycled. I’m planning on Acraglassing in a shim. It would be easier if it was material removal.  ETA: you can see what I concocted for a timing fix here on post 34: https://www.ar15.com/forums/ar-15/Who-here-is-using-a-FRT-with-a-22LR-What-is-your-setup-/130-790783/&page=3 |
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Quoted: ETA: you can see what I concocted for a timing fix here on post 34: https://www.ar15.com/forums/ar-15/Who-here-is-using-a-FRT-with-a-22LR-What-is-your-setup-/130-790783/&page=3 I have the opposite problem in another SS setup of mine, and needed to shim the rear side to keep the trip as far forward as possible to reliably delay hammer drop on the return. With that one, even with the shim, the hammer drops with a 0.185" gap between the bolt and the collar. That seems like a scary amount of space to me. I'm not familiar enough with the internal geometry to know whether the hammer is merely riding the bolt carrier home without making contact with the firing pin at that point, or whether that's a scenario where I'm gonna have a bad time. The BB SS trip doesn't seem to solve for that problem. 
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Quoted: With as many manufacturers of these as there are, we’re going to have problems with tolerances. Everyone wants drop-in magic. The reality is that they will likely need tuned, especially for .22lr. If that was in response to what I wrote, I don't think I said I expected drop-in magic at any point. In case it wasn't obvious in my prior posts, tuning is precisely what I'm trying to do. What I'm struggling with is a technique to delay engagement of the trip as the bolt carrier returns back to battery. I've already maxed out the forward rotation of the trip inside the safety. (I've tried two Hoffman style SSes from two different manufacturers.) There's theoretically plenty of space to do what I need, but I don't yet see a product available that affords that particular geometry. |
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Quoted: If that was in response to what I wrote, I don't think I said I expected drop-in magic at any point. In case it wasn't obvious in my prior posts, tuning is precisely what I'm trying to do. What I'm struggling with is a technique to delay engagement of the trip as the bolt carrier returns back to battery. I've already maxed out the forward rotation of the trip inside the safety. (I've tried two Hoffman style SSes from two different manufacturers.) There's theoretically plenty of space to do what I need, but I don't yet see a product available that affords that particular geometry. It wasn’t a response, it was an addition. |
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Quoted: For you guys that have dedicated bore buddy uppers that run well, did you opt for the “hand tuning” upgrade they recommend? Quoted: For you guys that have dedicated bore buddy uppers that run well, did you opt for the “hand tuning” upgrade they recommend? You're talking about this, right? VIP Tuning/Accurizing Package – We clean and preseason the bore with our proprietary bore paste to speed up break-in, hand polish the feed ramp to a mirror shine, and blend the chamber entrance to match it for ultra smooth feeding of all bullet profiles (including blunt match ammo). Match uppers will also have the barrels hand bedded to the upper. I did, because I wanted to test a variety of ammo. I don't know how much it matters, though. |
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Quoted: For you guys that have dedicated bore buddy uppers that run well, did you opt for the “hand tuning” upgrade they recommend? I don’t have a BB upper. With the exception of my Tac-Sol, the others were pieced together by me. I polished them with the Dremel and polishing compound with good results. I’ve been doing it since before it was stylish to do so. |
| Good to know. I just didn’t know if it really makes a difference. I can use a dremel and polishing compound, but if they were doing something different to change some geometry or make part of it move more smoothly and feed way more reliably then I would pony up for the hand tuning. But $175 is a lot on top of what they are already charging. |
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Quoted: Good to know. I just didn’t know if it really makes a difference. I can use a dremel and polishing compound, but if they were doing something different to change some geometry or make part of it move more smoothly and feed way more reliably then I would pony up for the hand tuning. But $175 is a lot on top of what they are already charging. I doubt any of the profiles are changed. Some people don’t know how to use tools and they’re catering to them. $175 buys a Dremel, polishing drums, compound and a lot of beer. |
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