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Posted: 1/15/2026 8:59:50 PM EDT
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with the solid plug in the back of the bolt of the AR9 offerings from PSA it doesn’t look like the levers from Atrius, or cornfire, or even the Kabuto will work with it. The 2 position WOT looks like it would work. Also don’t think the super safety will work with it either. Any options for 3 position FRT that works with the AR9 platform? Thanks Duke |
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The solid plug is a weight, which can be cut to fit FRTs. I use an Arizona Regulator in my H&R (PSA) gun, and a Rare Breed in my PSA PG-9. " /> " /> " />You need a heavy buffer with sliding weights, preferably Tungsten, or a hydraulic buffer to eliminate bolt bounce. |
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Originally Posted By jduke: with the solid plug in the back of the bolt of the AR9 offerings from PSA it doesn’t look like the levers from Atrius, or cornfire, or even the Kabuto will work with it. The 2 position WOT looks like it would work. Also don’t think the super safety will work with it either. Any options for 3 position FRT that works with the AR9 platform? Thanks Duke You mean without cutting your BCG weight? If it's a straight blow-back, you can try removing the BCG weight (you call a "plug") and making up the difference with a heavy PCC buffer. You probably want at least 22 oz. combined weight from your BCG and buffer. Assuming the rear of your bolt geometry is like an M16 carrier, lever-based FRTs should work. Hard to say without knowing more about your specific setup. (Pics might help.) |
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Originally Posted By gtsteve03: What about a binary trigger? Franklin is running a sale. Binary triggers are nowhere near as good as an FRT. Not even close. I took my binary out of its host gun the day I shot an FRT for the first time. It now lives in a 22. A Binary would have to be 40 dollars or under for me to buy one today, with the quality and quantity of FRTs on the market. And that would be merely to put in my parts bin for a rainy day. |
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Originally Posted By lugnutwrench2: You mean without cutting your BCG weight? If it's a straight blow-back, you can try removing the BCG weight (you call a "plug") and making up the difference with a heavy PCC buffer. You probably want at least 22 oz. combined weight from your BCG and buffer. Assuming the rear of your bolt geometry is like an M16 carrier, lever-based FRTs should work. Hard to say without knowing more about your specific setup. (Pics might help.) Mine looks pretty much the same as the pictures posted by elittlefield above with the exception of the weight (I called a plug) not being cut on mine. I have a mill, so I could certainly drop the weight in a vice and trim a little off of it to free up some area just above the lip on the bolt ‘carrier’ (yes I know its really just a big bolt on the AR9, not a carrier like it is on the AR15) If I only take a couple ounces off of the weight, would an H3 buffer be enough weight for the 9mm to function and still have enough mass to work the FRT? Duke |
| The only thing I am interested in putting a binary in is a 10/22 because I don’t think the 10/22 has enough margin to reliably run an FRT, I would certainly like to be proven wrong as I think there is even a bigger market for the 10/22 FRT than for the AR platform since it would be so much less expensive to feed. |
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Originally Posted By jduke: Mine looks pretty much the same as the pictures posted by elittlefield above with the exception of the weight (I called a plug) not being cut on mine. I have a mill, so I could certainly drop the weight in a vice and trim a little off of it to free up some area just above the lip on the bolt ‘carrier’ (yes I know its really just a big bolt on the AR9, not a carrier like it is on the AR15) If I only take a couple ounces off of the weight, would an H3 buffer be enough weight for the 9mm to function and still have enough mass to work the FRT? Duke Originally Posted By jduke: Originally Posted By lugnutwrench2: You mean without cutting your BCG weight? If it's a straight blow-back, you can try removing the BCG weight (you call a "plug") and making up the difference with a heavy PCC buffer. You probably want at least 22 oz. combined weight from your BCG and buffer. Assuming the rear of your bolt geometry is like an M16 carrier, lever-based FRTs should work. Hard to say without knowing more about your specific setup. (Pics might help.) Mine looks pretty much the same as the pictures posted by elittlefield above with the exception of the weight (I called a plug) not being cut on mine. I have a mill, so I could certainly drop the weight in a vice and trim a little off of it to free up some area just above the lip on the bolt ‘carrier’ (yes I know its really just a big bolt on the AR9, not a carrier like it is on the AR15) If I only take a couple ounces off of the weight, would an H3 buffer be enough weight for the 9mm to function and still have enough mass to work the FRT? Duke An H3 buffer is about 5.5 ounces. My traditional style 9mm buffer is 10 ounces. You really want the combined weight of your bolt and buffer to be about 22-23 ounces, including 4 Tungsten weights that slide. The pinned bolt weight only weighs about 2 ounces, the clearance cut made in there is a fraction of that amount. A different mechanism is to use a hydraulic buffer, which uses fluid being forced through small holes to damp the force being exerted as the bolt slams home. That's a little lighter. |
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Originally Posted By jduke: The only thing I am interested in putting a binary in is a 10/22 because I don’t think the 10/22 has enough margin to reliably run an FRT, I would certainly like to be proven wrong as I think there is even a bigger market for the 10/22 FRT than for the AR platform since it would be so much less expensive to feed. Agreed. If someone figures out a 10/22 FRT, they will make enormous money. The magazines for the 10/22 are so excellent. |
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Originally Posted By ELittlefield: An H3 buffer is about 5.5 ounces. My traditional style 9mm buffer is 10 ounces. You really want the combined weight of your bolt and buffer to be about 22-23 ounces, including 4 Tungsten weights that slide. The pinned bolt weight only weighs about 2 ounces, the clearance cut made in there is a fraction of that amount. A different mechanism is to use a hydraulic buffer, which uses fluid being forced through small holes to damp the force being exerted as the bolt slams home. That's a little lighter. I have never seen a hydraulic buffer for an AR, guess I will have to go look… |
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Originally Posted By jduke: I have never seen a hydraulic buffer for an AR, guess I will have to go look… Originally Posted By jduke: Originally Posted By ELittlefield: An H3 buffer is about 5.5 ounces. My traditional style 9mm buffer is 10 ounces. You really want the combined weight of your bolt and buffer to be about 22-23 ounces, including 4 Tungsten weights that slide. The pinned bolt weight only weighs about 2 ounces, the clearance cut made in there is a fraction of that amount. A different mechanism is to use a hydraulic buffer, which uses fluid being forced through small holes to damp the force being exerted as the bolt slams home. That's a little lighter. I have never seen a hydraulic buffer for an AR, guess I will have to go look… https://www.midwayusa.com/product/1024517894?srsltid=AfmBOoqyJCfoR5UCoxcGeSXG-DECPMmLnc2iubPzctKZSkOq3pVt6ChQ&pid=306223 |
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Originally Posted By jduke: I have never seen a hydraulic buffer for an AR, guess I will have to go look I know people use them without adding additional mass. I wouldn't and do not do this myself. Either kynshot buffer is 6oz, not enough buffer mass for blowback IMHO. Even an A5 receiver extension allowing the use of a single kynshot 2.5oz spacer weight along with the buffer and spring is the bare minimum giving around 22oz total mass depending on bolt weight for me. If you go with the Just right carbine receiver extention you can add an additional 2.5oz spacer weight 24-25oz total mass. I'm using the RB5007,a self made 3oz SS spacer weight in an A5 RE for my Novox SD barreled PSA AR-V. My AR-V bolt is really light at 12.6oz giving me just under 22oz overall mass. It runs great and with the 4.3" ported barrel bleeding pressure damn near as soon as the bullet leaves the case  it feels good and dosen't feel light on mass.
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Originally Posted By shultz: Kynshot RB5007 and RB5015HD. I know people use them without adding additional mass. I wouldn't and do not do this myself. Either kynshot buffer is 6oz, not enough buffer mass for blowback IMHO. Even an A5 receiver extension allowing the use of a single kynshot 2.5oz spacer weight along with the buffer and spring is the bare minimum giving around 22oz total mass depending on bolt weight for me. If you go with the Just right carbine receiver extention you can add an additional 2.5oz spacer weight 24-25oz total mass. I'm using the RB5007,a self made 3oz SS spacer weight in an A5 RE for my Novox SD barreled PSA AR-V. My AR-V bolt is really light at 12.6oz giving me just under 22oz overall mass. It runs great and with the 4.3" ported barrel bleeding pressure damn near as soon as the bullet leaves the case it feels good and dosen't feel light on mass.Originally Posted By shultz: Originally Posted By jduke: I have never seen a hydraulic buffer for an AR, guess I will have to go look I know people use them without adding additional mass. I wouldn't and do not do this myself. Either kynshot buffer is 6oz, not enough buffer mass for blowback IMHO. Even an A5 receiver extension allowing the use of a single kynshot 2.5oz spacer weight along with the buffer and spring is the bare minimum giving around 22oz total mass depending on bolt weight for me. If you go with the Just right carbine receiver extention you can add an additional 2.5oz spacer weight 24-25oz total mass. I'm using the RB5007,a self made 3oz SS spacer weight in an A5 RE for my Novox SD barreled PSA AR-V. My AR-V bolt is really light at 12.6oz giving me just under 22oz overall mass. It runs great and with the 4.3" ported barrel bleeding pressure damn near as soon as the bullet leaves the case it feels good and dosen't feel light on mass.Can you expand on that? I've been running a Kynshot with no additional weight in my Glock mag AR... I'm certainly willing to go to an A5 with a weight if you think it's necessary? I don't have a ton of rounds on the Kynshot gun yet. |
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Originally Posted By ELittlefield: That comports with what I thought I remembered with the Rare Breed over the summer. Good info, thank you! Originally Posted By ELittlefield: Originally Posted By Bye_Felicia: I dropped a Partisan into a PSA DOE and did not need to modify the bolt weight. That comports with what I thought I remembered with the Rare Breed over the summer. Good info, thank you! Yep, it ran extremely well. |
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Originally Posted By ELittlefield: Can you expand on that? I've been running a Kynshot with no additional weight in my Glock mag AR... I'm certainly willing to go to an A5 with a weight if you think it's necessary? I don't have a ton of rounds on the Kynshot gun yet. Until all this happens, it's literally nothing more than 6oz of mass. Colt designed the original AR9 with about 21.5 of total mass. Purpose built 9mm blowback PCC's generally have a bolt/total mass of 21oz or more. For the AR9 platform, total mass is all over the place...depends on what you buy and how much they wanted to cut cost. Bolt weights vary from about 12.5 up to about 16oz. I've seen AR9's sold with 5.5oz buffers and up. It's generally accepted that 22oz total mass is the beginning of the safe green zone for AR9's. This mass is keeping the bolt planted on the breach face when the rd fires, recoil spring rate has little impact. Decrease the mass and you increase the risk of the bolt opening to soon and case rupture, less mass the greater the risk. I mention total mass because again, bolt weights vary wildly depending on who made them and what magazine they were intended to work with. Weigh your bolt, then decide what buffer/weight combo gets you at or over 22oz. It's not that less mass won't work, it's a safety issue. Would I, do i worry I didn't hit 22oz with my AR-V SD, nope. I'm at 21.6oz total mass, close enough for me. Did I weigh my bolt and realize total mass was at 18.5oz with only the 5007 and decide I need more mass to make it safer to shoot, yep. My colt mag AR9's run closer to 24oz total mass when using 10oz 9mm extended buffers and the generally heavier colt style bolts. |
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Originally Posted By shultz: Sure. The kynshot doesn't really do anything for the first part of the cycle,only the end when buffer bottoms out in the RE then progressively slows the bolt via the piston until it bottoms out. Until all this happens, it's literally nothing more than 6oz of mass. Colt designed the original AR9 with about 21.5 of total mass. Purpose built 9mm blowback PCC's generally have a bolt/total mass of 21oz or more. For the AR9 platform, total mass is all over the place...depends on what you buy and how much they wanted to cut cost. Bolt weights vary from about 12.5 up to about 16oz. I've seen AR9's sold with 5.5oz buffers and up. It's generally accepted that 22oz total mass is the beginning of the safe green zone for AR9's. This mass is keeping the bolt planted on the breach face when the rd fires, recoil spring rate has little impact. Decrease the mass and you increase the risk of the bolt opening to soon and case rupture, less mass the greater the risk. I mention total mass because again, bolt weights vary wildly depending on who made them and what magazine they were intended to work with. Weigh your bolt, then decide what buffer/weight combo gets you at or over 22oz. It's not that less mass won't work, it's a safety issue. Would I, do i worry I didn't hit 22oz with my AR-V SD, nope. I'm at 21.6oz total mass, close enough for me. Did I weigh my bolt and realize total mass was at 18.5oz with only the 5007 and decide I need more mass to make it safer to shoot, yep. My colt mag AR9's run closer to 24oz total mass when using 10oz 9mm extended buffers and the generally heavier colt style bolts. Originally Posted By shultz: Originally Posted By ELittlefield: Can you expand on that? I've been running a Kynshot with no additional weight in my Glock mag AR... I'm certainly willing to go to an A5 with a weight if you think it's necessary? I don't have a ton of rounds on the Kynshot gun yet. Until all this happens, it's literally nothing more than 6oz of mass. Colt designed the original AR9 with about 21.5 of total mass. Purpose built 9mm blowback PCC's generally have a bolt/total mass of 21oz or more. For the AR9 platform, total mass is all over the place...depends on what you buy and how much they wanted to cut cost. Bolt weights vary from about 12.5 up to about 16oz. I've seen AR9's sold with 5.5oz buffers and up. It's generally accepted that 22oz total mass is the beginning of the safe green zone for AR9's. This mass is keeping the bolt planted on the breach face when the rd fires, recoil spring rate has little impact. Decrease the mass and you increase the risk of the bolt opening to soon and case rupture, less mass the greater the risk. I mention total mass because again, bolt weights vary wildly depending on who made them and what magazine they were intended to work with. Weigh your bolt, then decide what buffer/weight combo gets you at or over 22oz. It's not that less mass won't work, it's a safety issue. Would I, do i worry I didn't hit 22oz with my AR-V SD, nope. I'm at 21.6oz total mass, close enough for me. Did I weigh my bolt and realize total mass was at 18.5oz with only the 5007 and decide I need more mass to make it safer to shoot, yep. My colt mag AR9's run closer to 24oz total mass when using 10oz 9mm extended buffers and the generally heavier colt style bolts. Gotcha. I think I'll make that A5 upgrade. Who makes the weight you mentioned, to pair with an A5 tube and a 9mm Kynshot buffer? |
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Originally Posted By ELittlefield: Gotcha. I think I'll make that A5 upgrade. Who makes the weight you mentioned, to pair with an A5 tube and a 9mm Kynshot buffer? |
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Originally Posted By shultz: Kynshot makes 2.5oz 3/4" long SS spacer weights. Pair this with an A5/RB5007/5015HD. Since you're glock mag you have another consideration I can't help with...you want the bolt face to stop in the 1/8-1/4" sweet spot behind the bolt catch. If you have more that 1/4" consider adding a quarters. This gap is important for bolt catch health. I ended up making my own spacer weight for the AR-V out of SS. 3/4" wasn't enough length... I needed 1" due to the LRBHO location. I also wanted that extra 1/2oz vs quarters... Originally Posted By shultz: Originally Posted By ELittlefield: Gotcha. I think I'll make that A5 upgrade. Who makes the weight you mentioned, to pair with an A5 tube and a 9mm Kynshot buffer? Sweet, thanks. Ope, I just remembered it's an SB PDW brace assembly. No A5 length available for me. |
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Originally Posted By ELittlefield: Sweet, thanks. Ope, I just remembered it's an SB PDW brace assembly. No A5 length available for me. NO aluminum case stuff! Hell, I'm not sure if aluminum case 9mm range ammo is still produced... |
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Originally Posted By shultz: Weigh your bolt and kynshot together. If it were mine, and all I was shooting is 9mm brass/steel case FMJ range fodder... I'd be ok with anything over 20oz. Not that I'm reccomending you do such NO aluminum case stuff! Hell, I'm not sure if aluminum case 9mm range ammo is still produced... Originally Posted By shultz: Originally Posted By ELittlefield: Sweet, thanks. Ope, I just remembered it's an SB PDW brace assembly. No A5 length available for me. NO aluminum case stuff! Hell, I'm not sure if aluminum case 9mm range ammo is still produced... I'll weigh it next week. I don't own any aluminum ammo. |
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Originally Posted By shultz: Weigh your bolt and kynshot together. If it were mine, and all I was shooting is 9mm brass/steel case FMJ range fodder... I'd be ok with anything over 20oz. Not that I'm reccomending you do such [color=#ac860c]NO aluminum case stuff! Hell, I'm not sure if aluminum case 9mm range ammo is still produced... Curious. Why no aluminum case? I've got some, but haven't shot any with FRT. |
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Originally Posted By dps8204: Curious. Why no aluminum case? I've got some, but haven't shot any with FRT. Originally Posted By dps8204: Originally Posted By shultz: Weigh your bolt and kynshot together. If it were mine, and all I was shooting is 9mm brass/steel case FMJ range fodder... I'd be ok with anything over 20oz. Not that I'm reccomending you do such NO aluminum case stuff! Hell, I'm not sure if aluminum case 9mm range ammo is still produced... Curious. Why no aluminum case? I've got some, but haven't shot any with FRT. ROF has little to do with case rupture, it can happen just as easily at 1RPM as 1000RPM. |
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Originally Posted By ELittlefield: Binary triggers are nowhere near as good as an FRT. Not even close. I took my binary out of its host gun the day I shot an FRT for the first time. It now lives in a 22. A Binary would have to be 40 dollars or under for me to buy one today, with the quality and quantity of FRTs on the market. And that would be merely to put in my parts bin for a rainy day. Originally Posted By ELittlefield: Originally Posted By gtsteve03: What about a binary trigger? Franklin is running a sale. Binary triggers are nowhere near as good as an FRT. Not even close. I took my binary out of its host gun the day I shot an FRT for the first time. It now lives in a 22. A Binary would have to be 40 dollars or under for me to buy one today, with the quality and quantity of FRTs on the market. And that would be merely to put in my parts bin for a rainy day. I put a Franklin binary in my M4gery and it hasn't worked at all, even with an H3 buffer. Total waste of $. |
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Originally Posted By shultz: Sure. The Kynshot doesn't really do anything for the first part of the cycle, only the end when buffer bottoms out in the RE, then progressively slows the bolt via the piston until it bottoms out. Until all this happens, it's literally nothing more than 6oz of mass. Colt designed the original AR9 with about 21.5oz of total mass. Purpose-built 9mm blowback PCCs generally have a bolt/total mass of 21oz or more. For the AR9 platform, total mass is all over the place... depends on what you buy and how much they wanted to cut cost. Bolt weights vary from about 12.5oz up to about 16oz. I've seen AR9s sold with 5.5oz buffers and up. It's generally accepted that 22oz total mass is the beginning of the safe green zone for AR9s. This mass is keeping the bolt planted on the breech face when the round fires, recoil spring rate has little impact. Decrease the mass and you increase the risk of the bolt opening too soon and case rupture; less mass the greater the risk. I mention total mass because again, bolt weights vary wildly depending on who made them and what magazine they were intended to work with. Weigh your bolt, then decide what buffer/weight combo gets you at or over 22oz. It's not that less mass won't work, it's a safety issue. Would I, do I worry I didn't hit 22oz with my AR-V SD, nope. I'm at 21.6oz total mass, close enough for me. Did I weigh my bolt and realize total mass was at 18.5oz with only the 5007 and decide I need more mass to make it safer to shoot, yep. My Colt mag AR9s run closer to 24oz total mass when using 10oz 9mm extended buffers and the generally heavier Colt-style bolts. good info, thanks |
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Any updated information on which FRT, buffer and bolt combos for AR9s? Are there any non-blow back uppers advisable for a Glock style QC10 lower? I’ve been out of the game for years but hate my blow back AR9 that suppressed and has a binary trigger in it. The gas to face make it unshootable |
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Originally Posted By VeritatisUnus: Any updated information on which FRT, buffer and bolt combos for AR9s? Are there any non-blow back uppers advisable for a Glock style QC10 lower? I've been out of the game for years but hate my blow back AR9 that suppressed and has a binary trigger in it. The gas to face make it unshootable https://blowback9.wordpress.com I bought a 16" H&R upper and used a disrupter trigger and a KVP 10z bolt with four sliding tungsten weights. |
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