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[ARCHIVED THREAD] - New NFA S-9 Lower (Scorpion mags). Pics and build-in-progress with CMMG RDB (UPDATE 8/25 IT LIVES) (Page 2 of 4)
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Quoted: That's super cool! I'm interested to see if it works with other mags. I have a more CZ and Magpul mags than I do manticores. and I just got my CMMG upper working with my colt mag lower. It would require significant milling of the bolt carrier to work with mags with polymer feed lips, I am looking at possibly having that done. |
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Not sure anyone has interest in a simple blow back build with this, but I have an update. The magpul mags are hard to seat, unless you have the bolt open. This is even with an empty mag. The one magpul mag that I removed a bit from the top outter corner of the feedlips seats ok either way. The unmodified magpul mag would have trouble here and there stripping rounds from the mag...the modified one did not. Neither held the bolt back when empty. I am just using a cheap generic barrel from a different build and a KAK bolt. I have PSA mags arriving Monday and plan to go buy a factory CZ mag later today at a local shop. I only tested 5 rounds in 2 mags. The modified mag worked fine sans LRBO. Added..I using a NFA slick side C-5 upper. |
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Quoted: Not sure anyone has interest in a simple blow back build with this, but I have an update. The magpul mags are hard to seat, unless you have the bolt open. This is even with an empty mag. The one magpul mag that I removed a bit from the top outter corner of the feedlips seats ok either way. The unmodified magpul mag would have trouble here and there stripping rounds from the mag...the modified one did not. Neither held the bolt back when empty. I am just using a cheap generic barrel from a different build and a KAK bolt. I have PSA mags arriving Monday and plan to go buy a factory CZ mag later today at a local shop. I only tested 5 rounds in 2 mags. The modified mag worked fine sans LRBO. Added..I using a NFA slick side C-5 upper. Yeah, the Magpul feed lips are kinda thick. I did notice that they didn't activate the LRBHO near as well as the Manticore Arms mags, partly because they are kinda sloppy in the magwell and also the spring seems a bit weaker. Did you try trimming the BHO spring? That's what I did to make mine more reliable. |
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I did not trim the BHO spring. When I close my upper and lower it is hard to push together enough for the pins to slide in. It is doable, but not right. It appears that the ejector is acting as a fulcrum as it is a little high. I will adjust slightly by removing a small amount from the top of it, as it cannot be adjusted lower by design. I picked up a factory CZ mag and it fits the magwell much better and seems to LBO if I rack it nice and hard. I will test fire a few again this eve after my ejector shave...and using the factory mag. Hopefully my few minor issues go away...I believe they will. Glad I only bought 2 magpul mags to try, instead of going full on idiot and buying 10 before really testing them out. |
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Ran a handful of rounds through it again today. As of now, it will not lock thr bolt back with magoul or CZ mags with live fire or by hand. Will look into that more. I shot it with my other lower this time. I have a bianary trigger in it. I only got to try a small number of rounds in bianary. I wasn't shooting fast, just testing for double taps. With the the CZ mag the second round would fail to feed. With the magoul mag it would work. Odd.....but that is also part of the fun. Getting everything working right is satisfying in the end. |
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Quoted: Ran a handful of rounds through it again today. As of now, it will not lock thr bolt back with magoul or CZ mags with live fire or by hand. Will look into that more. I shot it with my other lower this time. I have a bianary trigger in it. I only got to try a small number of rounds in bianary. I wasn't shooting fast, just testing for double taps. With the the CZ mag the second round would fail to feed. With the magoul mag it would work. Odd.....but that is also part of the fun. Getting everything working right is satisfying in the end. Try trimming the BHO spring. Due to the way the LRBHO adapter works, it loses a lot of leverage. I trimmed about half the spring and it still keeps the BHO down just fine but makes it activate more reliably. |
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Quoted: Try trimming the BHO spring. Due to the way the LRBHO adapter works, it loses a lot of leverage. I trimmed about half the spring and it still keeps the BHO down just fine but makes it activate more reliably. Quoted: Quoted: Ran a handful of rounds through it again today. As of now, it will not lock thr bolt back with magoul or CZ mags with live fire or by hand. Will look into that more. I shot it with my other lower this time. I have a bianary trigger in it. I only got to try a small number of rounds in bianary. I wasn't shooting fast, just testing for double taps. With the the CZ mag the second round would fail to feed. With the magoul mag it would work. Odd.....but that is also part of the fun. Getting everything working right is satisfying in the end. Try trimming the BHO spring. Due to the way the LRBHO adapter works, it loses a lot of leverage. I trimmed about half the spring and it still keeps the BHO down just fine but makes it activate more reliably. I will try that. Thank you. |
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I trimmed the BHO spring and it seems to lock back almost every time when hand cycling...much better then before. It does this with the factory CZ mag. It never locks back with thr magpull mags. The very odd thing is that since I shortened the BHO spring, my upper comes together much better then before...who knew. The full length spring must have not let my seekins BHO sitting fully in place..or something. Anyway, 2 birds one stone sort of thing. Will test a few more live fire tonight or tomorrow. I have given up on the magpuls, but that is ok. Only bought 2. Thank you for the tip! Added: Success, that was the answer. Locks back in live fire with the CZ factory mag. S-9 compact (Other one done as money allows) New RD mount coming. The upper and lower colors match perfect in person. Attached File |
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Quoted: I trimmed the BHO spring and it seems to lock back almost every time when hand cycling...much better then before. It does this with the factory CZ mag. It never locks back with thr magpull mags. The very odd thing is that since I shortened the BHO spring, my upper comes together much better then before...who knew. The full length spring must have not let my seekins BHO sitting fully in place..or something. Anyway, 2 birds one stone sort of thing. Will test a few more live fire tonight or tomorrow. I have given up on the magpuls, but that is ok. Only bought 2. Thank you for the tip! Added: Success, that was the answer. Locks back in live fire with the CZ factory mag. S-9 compact (Other one done as money allows) New RD mount coming. The upper and lower colors match perfect in person. https://www.AR15.Com/media/mediaFiles/3591/20200829_201258_jpg-1569087.JPG Glad it worked. Interesting build you did. Would you mind taking some pics of the CZ feed lips so I can compare to the Magpuls? Curious if they might work with the CMMG RDB. |
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My PSA mags arrived today. Ran 2 rounds through each and feed fine and LRBHO worked. Tell me if you need them loaded in the pics, I can retake. Attached File Attached File |
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Quoted: My PSA mags arrived today. Ran 2 rounds through each and feed fine and LRBHO worked. Tell me if you need them loaded in the pics, I can retake. https://www.AR15.Com/media/mediaFiles/3591/20200831_162003_jpg-1571520.JPG https://www.AR15.Com/media/mediaFiles/3591/20200831_161957_jpg-1571522.JPG Looks to me like the Magpul feedlips are more squared off than any of the others, might make it easier to mod the RDB carrier to run with them. |
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An added note, the PSA mags fit the magwell better, like the factory CZ one. Both better fit then the magpuls. These PSA mags were $15 each. The plan is to go to the range tomorrow and actually get some rounds through this thing. I am waiting for my 2nd stripped upper, but will to try my complete upper on both lowers now to test function with multiple mags and ammo. P.S. my glock mag lowers are ugly now 
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The long one....with a few parts stolen from the compact model:) Attached File |
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I just picked up the 'last' S-9 lower. It's also a single digit serial number. They either sold these things in reverse order or made a tiny batch of < 10 receivers. I can see why the LRBHO seems kind of mickey mouse, but if it works it works. I have a Manticore arms mag and a factory CZ mag. The CZ one seems perfect but the Manticore rubs on the raised "12" in the magwell. I'll get some PSA mags as well. Now it's time to actually assemble a pistol out of this! |
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Quoted: I just picked up the 'last' S-9 lower. It's also a single digit serial number. They either sold these things in reverse order or made a tiny batch of < 10 receivers. I can see why the LRBHO seems kind of mickey mouse, but if it works it works. I have a Manticore arms mag and a factory CZ mag. The CZ one seems perfect but the Manticore rubs on the raised "12" in the magwell. I'll get some PSA mags as well. Now it's time to actually assemble a pistol out of this! Congrats! |
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Tomorrow is my plan to get out and run more mags and ammo through the "Long" version. See if it likes my PSA mags or my Factory CZ mags better. From there I will order more mags. I like it more each time I have shot it...even if it has only been a few rounds as a time. |
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Quoted: I just picked up the 'last' S-9 lower. It's also a single digit serial number. They either sold these things in reverse order or made a tiny batch of < 10 receivers. I can see why the LRBHO seems kind of mickey mouse, but if it works it works. I have a Manticore arms mag and a factory CZ mag. The CZ one seems perfect but the Manticore rubs on the raised "12" in the magwell. I'll get some PSA mags as well. Now it's time to actually assemble a pistol out of this! So you are the reason I couldn't get one....guess I will have to wait for the next batch. 
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Range outting went great. About 250 rounds fired through the S9. CZ and PSA mags are amazing...100% with LRBHO. The 1 of my 2 magpul mags that actually locks into the gun had feeding issues. Great fun! Also shot my CMMG RDB 9mm Banshee build and I cannot feel much difference in perceived recoil from this and the simple blowback S9. To ME, the RDB seems a little over rated. The RDB gun is lighter...which is nice. |
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The hybrid mags are back in stock at Preppers. Just FYI. Click here |
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Quoted: I trimmed the BHO spring and it seems to lock back almost every time when hand cycling...much better then before. It does this with the factory CZ mag. It never locks back with thr magpull mags. The very odd thing is that since I shortened the BHO spring, my upper comes together much better then before...who knew. The full length spring must have not let my seekins BHO sitting fully in place..or something. Anyway, 2 birds one stone sort of thing. Will test a few more live fire tonight or tomorrow. I have given up on the magpuls, but that is ok. Only bought 2. Thank you for the tip! Added: Success, that was the answer. Locks back in live fire with the CZ factory mag. S-9 compact (Other one done as money allows) New RD mount coming. The upper and lower colors match perfect in person. https://www.AR15.Com/media/mediaFiles/3591/20200829_201258_jpg-1569087.JPG That is super sexy. What upper is that? |
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Correct. I have a CMMG glock fed RDB gun also. I have more simple blow back guns and to be honest, they are more reliable and will run with a larger variety of loads....power lever, not necessarily bullet type. Nothing against the RDB stuff, but I think there are a little over rated. |
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Quoted: Correct. I have a CMMG glock fed RDB gun also. I have more simple blow back guns and to be honest, they are more reliable and will run with a larger variety of loads....power lever, not necessarily bullet type. Nothing against the RDB stuff, but I think there are a little over rated. Nicely done. The CZ mag setup looks aesthetically "right" to me, but I grew up seeing the MP5 as the dominant SMG. Macon Armory's feed cone fix for your direct blowback barrels would probably fix your bullet-type feeding issues. Both mine will eat anything. HST, truncated cone, truncated ball, etc. |
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Quoted: I’m planning on putting a three lug adapter on my pistol for my Obsidian 45. Any suggestions as to which one would work the best? I have two Rugged 3 lug adapters. I like that they have wrench flats on them, makes it easy to put on and remove should you need to. |
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Thanks for all the great advice. I'm really out of my element with blowback weapons on an AR platform. I bought a Ballistic Advantage 8.3-inch barrel and I'm wondering what bolt group would work the best with it. I was leaning towards the CMMG group, I've also thought about the new Frontier armor one, but it's out of stock (At least it was the other day when I checked their website). |
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Quoted: Thanks for all the great advice. I'm really out of my element with blowback weapons on an AR platform. I bought a Ballistic Advantage 8.3-inch barrel and I'm wondering what bolt group would work the best with it. I was leaning towards the CMMG group, I've also thought about the new Frontier armor one, but it's out of stock (At least it was the other day when I checked their website). I have that barrel, with a Faxon bolt running Endomags. Has been 100% since day 1 with every possible bullet profile in a variety of weights. |
[ARCHIVED THREAD] - New NFA S-9 Lower (Scorpion mags). Pics and build-in-progress with CMMG RDB (UPDATE 8/25 IT LIVES) (Page 2 of 4)
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