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Posted: 6/1/2026 9:04:24 PM EDT
[Last Edit: MudEagle][Edited]
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Does anyone have experience with the finish/build-it-yourself mini Kabuto kits from Area 43? I have a friend who bought one but hasn't attempted to polish the parts or assemble it yet, and the price seems attractive enough. I haven't seen the parts personally other than the photo on the website. Curious if anyone has built one and has an opinion on it. Do It Yourself Kabuto Kit Regular price $21.99 This video appears to be someone assembling one of the kits:  Mini Raptr (Mini Kabuto) drop in assembly |
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Originally Posted By HKH: They were originally named the F.A.R.T. And T.U.R.D. For a reason. It's fine if you don't like the mini-Kabuto design (I've had good luck with two of them, FWIW -- one printed at home and one all-steel example), but that's not what I'm asking in this non-GD thread. |
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Originally Posted By MudEagle: It's fine if you don't like the mini-Kabuto design (I've had good luck with two of them, FWIW -- one printed at home and one all-steel example), but that's not what I'm asking in this non-GD thread. The more FRTs the better. Is that website legit? |
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Originally Posted By MudEagle: It's fine if you don't like the mini-Kabuto design (I've had good luck with two of them, FWIW -- one printed at home and one all-steel example), but that's not what I'm asking in this non-GD thread. Brother, regarding FRTs, i can catch lightening in a bottle- but I’ve never been able to make those type run. I’ve got 3. One full size and two of the mini kubotos. I’d love to be able to use them but they definitely have kicked my ass. |
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Originally Posted By FreefallRet: For $22 why not. That's kind of where I am on it -- worst case is that I have some metal parts to swap into my existing 3D printed versions. But, I was hoping someone would have some firsthand experience with how much finishing these parts required, techniques they used in the finishing process, and dimensional accuracy of the unpolished raw parts. |
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Originally Posted By HKH: Brother, regarding FRTs, i can catch lightning in a bottle- but I’ve never been able to make those type run. I’ve got 3. One full size and two of the mini kubotos. I’d love to be able to use them but they definitely have kicked my ass. what is the issue? the Kabuto has become my favorite FRT, and I am replacing all my HTSS with these; I like the fact the Kabuto uses standard AR-15 semi-automatic fire control parts (NO M16 parts like the AZR 3-position requires), and with the KAK 3-position selector (trimmed via a 3D-printed jig), you can get Safe, Semi, FRT mode I have gotten almost a dozen to run reliably in various platforms; the majority simply dropped right in, and a few needed minor tuning (first tune the lever to the upper, and/or then tune the activator to the trigger/lower) |
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Originally Posted By hrt4me: what is the issue? the Kabuto has become my favorite FRT, and I am replacing all my HTSS with these; I like the fact the Kabuto uses standard AR-15 semi-automatic fire control parts (NO M16 parts like the AZR 3-position requires), and with the KAK 3-position selector (trimmed via a 3D-printed jig), you can get Safe, Semi, FRT mode I have gotten almost a dozen to run reliably in various platforms; the majority simply dropped right in, and a few needed minor tuning (first tune the lever to the upper, and/or then tune the activator to the trigger/lower) Care to share some more on this 1) tuning to upoer and 2) tuning to trigger/lower stuff (links maybe)? And, which form factor (small/med/large) became your happy place? I have 2x large and one stainless small form factor Kabutos. The 2 large are poly/metal. Both gave hints of success but were ultimately replaced with other fire controls. I have yet to try the small form factor stainless example. Unlike @HKH, I can't bottle lightning. And, I honestly think I can get'm to run - 'bout certain I can with some tuning advisement. I presently have one lower sitting w/o a fire control group (raided to run another lower) and another stripped lower to bring online - maybe it's time to run a Kabuto. |
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Originally Posted By hrt4me: what is the issue? the Kabuto has become my favorite FRT, and I am replacing all my HTSS with these; I like the fact the Kabuto uses standard AR-15 semi-automatic fire control parts (NO M16 parts like the AZR 3-position requires), and with the KAK 3-position selector (trimmed via a 3D-printed jig), you can get Safe, Semi, FRT mode I have gotten almost a dozen to run reliably in various platforms; the majority simply dropped right in, and a few needed minor tuning (first tune the lever to the upper, and/or then tune the activator to the trigger/lower) Ok Brother I’m asking for help. I know you’re a busy guy. If you could do a breakdown on how You tune? Issues faced? Here’s mine: 1. Binding- do I trim lever or upper? 2. Goes FRT in Semi on function check 3. Will not go FRT in 3rs position 4. High or low shelf? Or doesn’t matter. 5. Lower / upper won’t close for takedown pin Like I said, I’ve got 3 and they sit in a bag in the safe with all the spares. It’d be cool to get these to run. |
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Try this (warning: Reddit link to detailed post about how Kabutos work and how they are tuned): Why sizing your "Drop in" is vital and needed to prevent binding and cracked housings More about how Kabutos work in this 3D printed offering: U-DIS (Universal Drop In System) Geissele, LaRue, Schmid, milspec, CMC, Rise armament trigger and M16 safety compatibile  February 13, 2026 |
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Originally Posted By dredeagle: Care to share some more on this 1) tuning to upoer and 2) tuning to trigger/lower stuff (links maybe)? And, which form factor (small/med/large) became your happy place? I have 2x large and one stainless small form factor Kabutos. The 2 large are poly/metal. Both gave hints of success but were ultimately replaced with other fire controls. I have yet to try the small form factor stainless example. Unlike @HKH, I can't bottle lightning. And, I honestly think I can get'm to run - 'bout certain I can with some tuning advisement. I presently have one lower sitting w/o a fire control group (raided to run another lower) and another stripped lower to bring online - maybe it's time to run a Kabuto. the mini-Kabuto fits into the Auto Sear pocket of the upper receiver, so you may have to trim and smooth the top rear of the lever ever so slightly so the bolt carrier moves freely without binding then either Kabuto (mini- or full-size) in the lower receiver, you may need to trim (shorten) the activator ever so slightly so there is a small gap between the bottom of the activator and top of trigger... the Reddit link @MudEagle posted describes all this in more detail |
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Originally Posted By HKH: Ok Brother I’m asking for help. I know you’re a busy guy. If you could do a breakdown on how You tune? Issues faced? Here’s mine: 1. Binding- do I trim lever or upper? 2. Goes FRT in Semi on function check 3. Will not go FRT in 3rs position 4. High or low shelf? Or doesn’t matter. 5. Lower / upper won’t close for takedown pin 1. No need to trim anything on upper (nor lower); you may have to trim lever, but more likely the activator length ever so slightly 2. FRT in Semi means the Activator is too long, so carefully shorten it till Semi position is actually Semi; be careful NOT to trim too much, because then the Activator becomes useless for mil-spec trigger (but short activator works for LaRue MBT and maybe other 2-stage triggers) 3. once you get semi-automatic in Semi position, then you will eventually get FRT in 3rd position 4. all mine are low shelf, but I believe I read that does not matter 5. if upper won't close onto lower, then that is potentially an issue with the housing... I have never experienced that issue |
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FRT in Semi (2nd position) and binding in FRT (3rd position) means the Activator leg is too long. Shaving down that leg will eventually make Semi semi-automatic and transfer the FRT over to the 3rd position. What is currently happening now is the Kabuto's Activator leg is resetting the trigger in Semi, and then when the selector is in the 3rd position, it pushes the Activator back to have a longer throw for resetting for FRT (but the trigger is already fully reset in Semi, so the trigger has no more room to move to let the lever go past in order for the bolt carrier to move - hence your bindng) |
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Doing the Kabuto with the U-DIS pack and all 3D printed parts, I found there was a lot of variation in different guns/triggers with regard to the length of the activator, as recommended above. Also the slight rounding on the rear corner of the activator leg is a bit important because in SA the activator will pivot forward and slide that corner along the top of the trigger in order to get out of the way and not force it to reset. I even found one ALG trigger where I had to widen the activator leg about a mm in the CAD file because the rear surface on the trigger was rounded so much the leg would just slip off the side of it instead of doing the forced reset. Overall, being able to modify or edit the activator part around that leg is the key to getting this design to run right. The companies doing metal ones would do well to either offer it with an "oversized" part that requires you to fit down to size, or offer a few options for that part with different lengths. |
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I bought this one from Dogwood Armory. It doesn't fit snugly in the upper pocket, and bursts on semi auto mode when I first tried it. I'm reluctant to try again. How can it consistently do its job if it can jostle side to side and twist around? It's just sloppily built in comparison to how tight and precise the Arizona Regulator is.  " /> " />
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Originally Posted By hrt4me: what is the issue? the Kabuto has become my favorite FRT, and I am replacing all my HTSS with these; I like the fact the Kabuto uses standard AR-15 semi-automatic fire control parts (NO M16 parts like the AZR 3-position requires), and with the KAK 3-position selector (trimmed via a 3D-printed jig), you can get Safe, Semi, FRT mode I have gotten almost a dozen to run reliably in various platforms; the majority simply dropped right in, and a few needed minor tuning (first tune the lever to the upper, and/or then tune the activator to the trigger/lower) Originally Posted By hrt4me: Originally Posted By HKH: Brother, regarding FRTs, i can catch lightning in a bottle- but I’ve never been able to make those type run. I’ve got 3. One full size and two of the mini kubotos. I’d love to be able to use them but they definitely have kicked my ass. what is the issue? the Kabuto has become my favorite FRT, and I am replacing all my HTSS with these; I like the fact the Kabuto uses standard AR-15 semi-automatic fire control parts (NO M16 parts like the AZR 3-position requires), and with the KAK 3-position selector (trimmed via a 3D-printed jig), you can get Safe, Semi, FRT mode I have gotten almost a dozen to run reliably in various platforms; the majority simply dropped right in, and a few needed minor tuning (first tune the lever to the upper, and/or then tune the activator to the trigger/lower) Just so I have the nomenclature right, are you talking about the all metal ones like I just posted? Or the larger, polymer framed ones that fit snugly down into the lower? I bought one of each, to evaluate them and add them to my FRT guide. Or maybe you're talking about something else entirely? I'm very late to the game on this design. |
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Originally Posted By hrt4me: 1. No need to trim anything on upper (nor lower); you may have to trim lever, but more likely the activator length ever so slightly 2. FRT in Semi means the Activator is too long, so carefully shorten it till Semi position is actually Semi; be careful NOT to trim too much, because then the Activator becomes useless for mil-spec trigger (but short activator works for LaRue MBT and maybe other 2-stage triggers) 3. once you get semi-automatic in Semi position, then you will eventually get FRT in 3rd position 4. all mine are low shelf, but I believe I read that does not matter 5. if upper won't close onto lower, then that is potentially an issue with the housing... I have never experienced that issue Originally Posted By hrt4me: Originally Posted By HKH: Ok Brother I’m asking for help. I know you’re a busy guy. If you could do a breakdown on how You tune? Issues faced? Here’s mine: 1. Binding- do I trim lever or upper? 2. Goes FRT in Semi on function check 3. Will not go FRT in 3rs position 4. High or low shelf? Or doesn’t matter. 5. Lower / upper won’t close for takedown pin 1. No need to trim anything on upper (nor lower); you may have to trim lever, but more likely the activator length ever so slightly 2. FRT in Semi means the Activator is too long, so carefully shorten it till Semi position is actually Semi; be careful NOT to trim too much, because then the Activator becomes useless for mil-spec trigger (but short activator works for LaRue MBT and maybe other 2-stage triggers) 3. once you get semi-automatic in Semi position, then you will eventually get FRT in 3rd position 4. all mine are low shelf, but I believe I read that does not matter 5. if upper won't close onto lower, then that is potentially an issue with the housing... I have never experienced that issue Ah. Interesting. Do your mini, all steel (still not 100% sure on the nomenclature) units like I just posted fit very loosely in the upper sear pocket? |
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Originally Posted By ELittlefield: Ah. Interesting. Do your mini, all steel (still not 100% sure on the nomenclature) units like I just posted fit very loosely in the upper sear pocket? Hmmm. Like I stated yesterday, I haven't gotten 'round tuit. But, I've seen the mini (similar to the one you just posted) tucked into the space between the trigger and safety in the lower. On mine, none of the levers are coated. The version at this link appears similar. Reading down fitment is described as "locating on top of the safety." So, is it designed for install in the upper's sear pocket? I have not chased the Reddit instructions linked above, so I truly don't know. |
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Originally Posted By ELittlefield: Just so I have the nomenclature right, are you talking about the all metal ones like I just posted? Or the larger, polymer framed ones that fit snugly down into the lower? I bought one of each, to evaluate them and add them to my FRT guide. Or maybe you're talking about something else entirely? I'm very late to the game on this design. Originally Posted By ELittlefield: Originally Posted By hrt4me: Originally Posted By HKH: Brother, regarding FRTs, i can catch lightning in a bottle- but I’ve never been able to make those type run. I’ve got 3. One full size and two of the mini kubotos. I’d love to be able to use them but they definitely have kicked my ass. what is the issue? the Kabuto has become my favorite FRT, and I am replacing all my HTSS with these; I like the fact the Kabuto uses standard AR-15 semi-automatic fire control parts (NO M16 parts like the AZR 3-position requires), and with the KAK 3-position selector (trimmed via a 3D-printed jig), you can get Safe, Semi, FRT mode I have gotten almost a dozen to run reliably in various platforms; the majority simply dropped right in, and a few needed minor tuning (first tune the lever to the upper, and/or then tune the activator to the trigger/lower) Just so I have the nomenclature right, are you talking about the all metal ones like I just posted? Or the larger, polymer framed ones that fit snugly down into the lower? I bought one of each, to evaluate them and add them to my FRT guide. Or maybe you're talking about something else entirely? I'm very late to the game on this design. I have both full-sized versions, as well as mini versions, all metal (I also have printed versions of each, but I prefer the metal ones) all versions (full-size and mini) seat and fit snugly in their respective positions IN THE LOWER... even the mini-Kabutos drop into the lower (and then I close the upper down onto them)... I had no idea how snugly the mini-Kabutos fit into the upper receiver pocket until I did the first part of tuning them, i.e. determining whether the bolt carrier cleared the lever smoothly... only then did I see the mini-Kabuto housing lips fit snugly into the upper receiver pocket... but definitely not loose as depicted in that photo you posted |
| I think with the mini housing, even if that oval ridge that goes into the cut in the upper isn't a perfect fit there, it should still hold tight in the lower because of the little "ears" that fit into the rounded corners of the FCG area in the lower plus the upper clamping down on that area. That's what mostly holds down the large housing too even without the raised oval part. |
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Well, received a couple of these Area 43 kits. Whew...they are pretty rough. I mean, they say that the parts need finishing, but they really mean it. They are just raw laser cuts, and in many places not even actually square. In the video I posted in the OP, the parts are just given a general clean-up with a sanding disc and assembled; there's no way to tell if it will actually function with only that level of clean-up. I'm foreseeing a bunch of time with files, sandpaper, dremel sanding drums, stones, and flitz in my future. This pic is after I'd already starting running a file across the flats to get rid of the obvious jagged pieces from the laser cutting. Attached File |
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Well I decided to just assemble this thing and check it out for function without spending much time doing smoothing and shaping of the pieces. The mating surfaces were sort of smoothed, but were nowhere near as slick as I'd envisioned originally making them. So I put some Flitz where they'd be sliding against each other and added a little oil to make some polishing lubricant, lol. Turns out...it worked great! Put it in a 16" carbine with an H2 buffer and it functioned perfectly without any tweaking to the leg length. The kit comes with a 3D printed 3-position selector which looked ugly but worked fine. I also tried it with a Datum Machine M16 3-position selector and that worked great, too. Overall awesome that a $25 delivered kit that is only mildly "finished" got the job done. Attached File |
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