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Neat rifle. I remember when they were released back in 07 or so.
I don't know enough about the design to be helpful unfortunately. |
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"History teaches us that men and nations behave wisely once they have exhausted all other alternatives."-Abba Eban
"I like it both ways, but still mainly mouth it" -gonzo_beyondo |
OP, you might look into a gas port bushing. That will lower the amount of gas coming into the system.
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Death to quislings.
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Originally Posted By Scrapple: I don't know much about these. Would be interested in knowing more. View Quote View All Quotes View All Quotes Originally Posted By Scrapple: Originally Posted By backbencher: OP, you might look into a gas port bushing. That will lower the amount of gas coming into the system. I don't know much about these. Would be interested in knowing more. Well, you don't want to weld on the bbl to plug up the gas port & redrill it. So you use an endmill to enlarge the area around the gas port, then you put a bushing in the new shallow hole, and the bushing has a smaller diameter than the existing gas port. Commonly used on Mini-14s, we generally have other options for ARs, but clearly you don't. A replacement bbl actually wouldn't be all that much since you're using a stock AR bolt, which means the bbl is very likely using a stock AR barrel extension. White Oak barrel extension, your bolt, & Green Mountain barrel blank, send it to these guys w/ your specs: https://tp555.com/ They did me a beautiful 27" pencil bbl for my oldest's Christmas present one year. |
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Death to quislings.
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Originally Posted By backbencher: Well, you don't want to weld on the bbl to plug up the gas port & redrill it. So you use an endmill to enlarge the area around the gas port, then you put a bushing in the new shallow hole, and the bushing has a smaller diameter than the existing gas port. Commonly used on Mini-14s, we generally have other options for ARs, but clearly you don't. A replacement bbl actually wouldn't be all that much since you're using a stock AR bolt, which means the bbl is very likely using a stock AR barrel extension. White Oak barrel extension, your bolt, & Green Mountain barrel blank, send it to these guys w/ your specs: https://tp555.com/ They did me a beautiful 27" pencil bbl for my oldest's Christmas present one year. View Quote Interesting information. I suppose that it would be possible to have a custom barrel made. Any other ideas, just to have options? |
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"I noticed that when I fire the rifle with the magazine resting on the shooting platform, the issue returns."
Is it possible, your mags feed lips are "dragging" on the carrier group ? Maybe a new mag catch could help ? |
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*Hold on to your AR-15s. Their magic must be very powerful, or they wouldn’t want them.*
JAFOM.... Just another fat old man. ________________________________ TOGC,IADC |
Another alternative would be to get an adjustable gas carrier, move the proprietary key to that, and chop off the tail. Not easy, but no barrel work, no disassembly of the gas system on the barrel. And now you have adjustable gas.
I like the new barrel idea though, you could get a 14.7" pinned & welded pencil, drop some weight. |
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Death to quislings.
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Originally Posted By bfoosh06: "I noticed that when I fire the rifle with the magazine resting on the shooting platform, the issue returns." Is it possible, your mags feed lips are "dragging" on the carrier group ? Maybe a new mag catch could help ? View Quote View All Quotes View All Quotes Originally Posted By bfoosh06: "I noticed that when I fire the rifle with the magazine resting on the shooting platform, the issue returns." Is it possible, your mags feed lips are "dragging" on the carrier group ? Maybe a new mag catch could help ? Oh I'm sure that's happening, but the point is that the rifle is so sensitive to both bounce that that is causing an issue, so I'm hoping to mitigate the bolt bounce and over gassing as much as I can. Originally Posted By backbencher: Another alternative would be to get an adjustable gas carrier, move the proprietary key to that, and chop off the tail. Not easy, but no barrel work, no disassembly of the gas system on the barrel. And now you have adjustable gas. I like the new barrel idea though, you could get a 14.7" pinned & welded pencil, drop some weight. I was also thinking about doing that, but I'm not all that familiar with those adjustable carriers. Feel free to post more details, but if you think that there is a version out there that would be compatible with this gas key, then I am very interested. The idea of creating a new barrel isn't bad, but if I can keep this set up as is and then have adjustable gas through the carrier, that does sound pretty good. Originally Posted By Dano523: Is the gas block not adjustable on this rig? http://i.imgur.com/aXBJMYW.jpg As for bolt bounce, should not be a problem since not running rig in full auto, and if the bolt is not locking back up after the bounce, then not lubing with CLP to begin with, or something has major binding instead. Lastly, when was the last time the recoil spring was replaced, since that needs to happen every 4K rounds. Also if gas block is not adjustable, then may want to thing about going to extra tension recoil springs. If you run into the problem of not able to find replacement recoil springs, then Brownells sells spring stock, and you can make your own replacement springs. That adjustable gas block is from an old post on this website, and it was a custom job done by the owner of that rifle. I would consider doing that as well, and would love to hear from him on how he did it, and how it worked out. Nothing is binding in the action, it feels very smooth, but as I mentioned earlier any added friction such as new gas rings or the magazine feed lips pushing upwards on the bottom of the bolt carrier causes it to fail to return all the way forwards. The recoil spring is pretty much brand new. I considered asking springco to make me a custom stiffer spring, but this one is already quite stiff. I currently have a spare spring for this as well. |
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OP, for a replacement carrier, might look into the Bootleg Inc adjustable gas carrier. I can't get to their site right now, which is weird.
How does your gas key attach to your existing carrier? Just 2 normal screws or something else? |
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Death to quislings.
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Originally Posted By backbencher: OP, for a replacement carrier, might look into the Bootleg Inc adjustable gas carrier. I can't get to their site right now, which is weird. How does your gas key attach to your existing carrier? Just 2 normal screws or something else? View Quote Yeah their website is down for me also. I did some digging and that's the one that I found that seems to adjust internally, regardless of the gas key. The gas key screws in the same way, so it shouldn't be an issue to install it... Might be tough to remove from its current carrier, however. |
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Originally Posted By Scrapple: Yeah their website is down for me also. I did some digging and that's the one that I found that seems to adjust internally, regardless of the gas key. The gas key screws in the same way, so it shouldn't be an issue to install it... Might be tough to remove from its current carrier, however. View Quote View All Quotes View All Quotes Originally Posted By Scrapple: Originally Posted By backbencher: OP, for a replacement carrier, might look into the Bootleg Inc adjustable gas carrier. I can't get to their site right now, which is weird. How does your gas key attach to your existing carrier? Just 2 normal screws or something else? Yeah their website is down for me also. I did some digging and that's the one that I found that seems to adjust internally, regardless of the gas key. The gas key screws in the same way, so it shouldn't be an issue to install it... Might be tough to remove from its current carrier, however. All screws must yield to a drill press. |
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Death to quislings.
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Originally Posted By backbencher: OP, for a replacement carrier, might look into the Bootleg Inc adjustable gas carrier. I can't get to their site right now, which is weird. How does your gas key attach to your existing carrier? Just 2 normal screws or something else? View Quote On the ZM the key is pocketed into the carrier. Attached File |
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Originally Posted By RDTCU: On the ZM the key is pocketed into the carrier. https://www.ar15.com/media/mediaFiles/173511/1000003781_png-3135755.JPG View Quote View All Quotes View All Quotes Originally Posted By RDTCU: Originally Posted By backbencher: OP, for a replacement carrier, might look into the Bootleg Inc adjustable gas carrier. I can't get to their site right now, which is weird. How does your gas key attach to your existing carrier? Just 2 normal screws or something else? On the ZM the key is pocketed into the carrier. https://www.ar15.com/media/mediaFiles/173511/1000003781_png-3135755.JPG So he's gonna need a mill. New barrel might be the simplest, and allows you to drop some weight up front as well, OP. 14.7" P&W pencil! Is the external diameter of the barrel extension 1"? |
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Death to quislings.
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OP, what gas rings are you using?
Did you scrape and clean the bore in the carrier? New rings in a dirty bolt chamber will drag. 1-piece rings are garbage and should never be used IMO... I had similar issues with my own bufferless build early on and found that headspace was on the tight side. If your issues started with a new bolt that's where i'd start. |
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Fabricate a new gas tube, with the rear part tapped for set screws with various sized holes bored through them, to act as replaceable gas jets?
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To vote for, sign, or enforce a blatently unconstitutional law, without amending the Constitution, is a direct attack on the Constitution, and therefore; treason.
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I'll see if i can find it in the parts bin but the carrier i have has a shallow pocket milled to accept the key footprint.
The pocket takes the shear loads so you don't snap the key bolts. On my build i keyed the key to the shortened standard carrier with a hollow bushing around the gas port. |
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Originally Posted By Dano523: https://i.ibb.co/MMQ7SGN/20240220-190526.jpg Not able to add an adjustable gas bolt to key since gas tube is welded to top of carrier, gas passage in front of the bolts,and adjuster would have to go through the bolts, unless threaded channel to front side of key isntead. http://i.imgur.com/aXBJMYW.jpg So would be easy to intercept the gas passage at the front block, drip and tap it for set screw shown above Hence figure out size of gas passage on block, to come up with a set screw that is wider than it, drill the intercept channel for set screw to other side of passage void, go in with 90 degree drill bit to V channel the other side, shorten and 90degree the end of the set screw, and you now have a gas adjuster that can not only close off the gas passage in the block, but backed off to open the gas port as needed to reduce the amount of pressure out of the barrel port to B/C, so bolt is not opening too soon to cause the rig to over function. Also to point out, front channel as also been drilled and taped, for a jam screw to hold the adjustment set screw in place. So front jam set screw is loosened, side gas screws is set to just allow the bolt to lock back on last round out of mag, turned out another 1/8" for good messure to add just a touch more gas, and then jam screw is tighen into side of set screw, to retain in in place. If machining is beyond our skill level, then check with the local guys, since one may be a machinist to do the work for you. It a 5 min job if you know what your doing, and really just paint by numbers using the DRO. This will at least resolve the bolt opening too soon for the ammo in play, and may slightly help with the bolt bounce. I say slightly, since will reduce the amount of carrier slamming into the back buffer too cause the carrier to be sling shoot off it, but without a buffer in play as the bolt does go to lock up, still going to have the carrier bouncing back off the face of barrel extension at lock up. As for carrier on the rig, it just a cut standard AR10 carrier, and you can tell that its a AR10 carrier, since the hammer for it uses is the narrow type, while a DPMS/stoner carrier uses the wide type hammer isntead (wider hammer will bind in the ar-10 lower carrier opening). https://i.ibb.co/MGB1pzy/20240219-175756.jpg View Quote Wait, what? It's a chopped AR-15 carrier. |
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Death to quislings.
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Originally Posted By Dano523: Yep, and just different type gas key. Take a close look and can see the standard ramps for the FA, when the standard carrier was cut to shorten it to work without an receiver extension void area. Hence back FA receiver as cut in half, and you would never machine a carrier from scratch, to have the back half of FA detent still in play. https://i.ibb.co/JdQWjgw/20240220-190103.jpg So only thing special on the carrier, is just welded on long tube key. View Quote Looks like the long gas key is bolted to an adapter that is bolted to a standard chopped carrier, Dano. |
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Death to quislings.
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Originally Posted By Dano523: https://i.ibb.co/MMQ7SGN/20240220-190526.jpg Not able to add an adjustable gas bolt to key since gas tube is welded to top of carrier, gas passage in front of the bolts,and adjuster would have to go through the bolts, unless threaded channel to front side of key isntead. Also to point out, if dead blow effect device was to be added to keep the carrier from bouncing off the back of barrel extension, it would need to be added to the extended key. With it not solid, front tube welded to top of carrier, such a device on the extended from end of the key front end, would just cause the weld to break in time. http://i.imgur.com/aXBJMYW.jpg So would be easy to intercept the gas passage at the front block, drill and tap for set screws shown above Hence figure out size of gas passage on block, to come up with a set screw that is wider than it, drill the intercept channel for set screw to other side of passage void, go in with 90 degree drill bit to V channel the other side, shorten and 90degree the end of the set screw, and you now have a gas adjuster that can not only close off the gas passage in the block, but backed off to open the gas port as needed to reduce the amount of pressure out of the barrel port to B/C, so bolt is not opening too soon to cause the rig to over function. Also to point out, front channel as also been drilled and taped, for a jam screw to hold the adjustment set screw in place. So front jam set screw is loosened, side gas screws is set to just allow the bolt to lock back on last round out of mag, turned out another 1/8" for good messure to add just a touch more gas, and then jam screw is tighen into side of set screw, to retain in in place. If machining is beyond our skill level, then check with the local guys, since one may be a machinist to do the work for you. It a 5 min job if you know what your doing, and really just paint by numbers using the DRO. This will at least resolve the bolt opening too soon for the ammo in play, and may slightly help with the bolt bounce. I say slightly, since will reduce the amount of carrier slamming into the back buffer too cause the carrier to be sling shoot off it, but without a buffer in play as the bolt does go to lock up, still going to have the carrier bouncing back off the face of barrel extension at lock up. As for carrier on the rig, it just a cut standard AR carrier, and you can tell that its a AR10 carrier, since the hammer for it uses is the narrow type, while a DPMS/stoner carrier uses the wide type hammer isntead (wider hammer will bind in the ar-10 lower carrier opening). https://i.ibb.co/MGB1pzy/20240219-175756.jpg As why it never caught on (even with it being a folder that should have sold like hotcakes for para use), it was due to lack of buffer to control bolt bounce for full auto fire in the first place. Hence sear release gap will grow as the hammer rear tab and auto sear wear, with to much service time to keep that in check at .083" so you don't have problems with fail to fire in full auto to start with, and semi with the carrier not fully returning to be tight against barrel extension at trigger pull. With buffer system, you can have an auto sear gap grow well into the .100" range, and since the buffer will keep the carrier from bouncing off the barrel extension, don't run into fail to fire problems with FP being block/bolt staying locked up at feed to begin with. View Quote This sounds very complex, and I have no machining capability. That said, I am interested in improving the performance of this rifle somehow, and reducing the gas flow would accomplish that. |
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Originally Posted By Scrapple: This sounds very complex, and I have no machining capability. That said, I am interested in improving the performance of this rifle somehow, and reducing the gas flow would accomplish that. View Quote View All Quotes View All Quotes Originally Posted By Scrapple: Originally Posted By Dano523: https://i.ibb.co/MMQ7SGN/20240220-190526.jpg Not able to add an adjustable gas bolt to key since gas tube is welded to top of carrier, gas passage in front of the bolts,and adjuster would have to go through the bolts, unless threaded channel to front side of key isntead. Also to point out, if dead blow effect device was to be added to keep the carrier from bouncing off the back of barrel extension, it would need to be added to the extended key. With it not solid, front tube welded to top of carrier, such a device on the extended from end of the key front end, would just cause the weld to break in time. http://i.imgur.com/aXBJMYW.jpg So would be easy to intercept the gas passage at the front block, drill and tap for set screws shown above Hence figure out size of gas passage on block, to come up with a set screw that is wider than it, drill the intercept channel for set screw to other side of passage void, go in with 90 degree drill bit to V channel the other side, shorten and 90degree the end of the set screw, and you now have a gas adjuster that can not only close off the gas passage in the block, but backed off to open the gas port as needed to reduce the amount of pressure out of the barrel port to B/C, so bolt is not opening too soon to cause the rig to over function. Also to point out, front channel as also been drilled and taped, for a jam screw to hold the adjustment set screw in place. So front jam set screw is loosened, side gas screws is set to just allow the bolt to lock back on last round out of mag, turned out another 1/8" for good messure to add just a touch more gas, and then jam screw is tighen into side of set screw, to retain in in place. If machining is beyond our skill level, then check with the local guys, since one may be a machinist to do the work for you. It a 5 min job if you know what your doing, and really just paint by numbers using the DRO. This will at least resolve the bolt opening too soon for the ammo in play, and may slightly help with the bolt bounce. I say slightly, since will reduce the amount of carrier slamming into the back buffer too cause the carrier to be sling shoot off it, but without a buffer in play as the bolt does go to lock up, still going to have the carrier bouncing back off the face of barrel extension at lock up. As for carrier on the rig, it just a cut standard AR carrier, and you can tell that its a AR10 carrier, since the hammer for it uses is the narrow type, while a DPMS/stoner carrier uses the wide type hammer isntead (wider hammer will bind in the ar-10 lower carrier opening). https://i.ibb.co/MGB1pzy/20240219-175756.jpg As why it never caught on (even with it being a folder that should have sold like hotcakes for para use), it was due to lack of buffer to control bolt bounce for full auto fire in the first place. Hence sear release gap will grow as the hammer rear tab and auto sear wear, with to much service time to keep that in check at .083" so you don't have problems with fail to fire in full auto to start with, and semi with the carrier not fully returning to be tight against barrel extension at trigger pull. With buffer system, you can have an auto sear gap grow well into the .100" range, and since the buffer will keep the carrier from bouncing off the barrel extension, don't run into fail to fire problems with FP being block/bolt staying locked up at feed to begin with. This sounds very complex, and I have no machining capability. That said, I am interested in improving the performance of this rifle somehow, and reducing the gas flow would accomplish that. Don't say no machining capability. You have a drill & a Dremel, no? It would seem your fancy gas key would bolt right on to a Bootleg carrier. Their website is back up: https://bootleginc.com/ That would give you the most control, and you can always have a pencil barrel to drop weight later. |
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Death to quislings.
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Originally Posted By backbencher: Don't say no machining capability. You have a drill & a Dremel, no? It would seem your fancy gas key would bolt right on to a Bootleg carrier. Their website is back up: https://bootleginc.com/ That would give you the most control, and you can always have a pencil barrel to drop weight later. View Quote It won't just bolt up. The ZM key is keyed into the carrier. |
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Originally Posted By RDTCU: It won't just bolt up. The ZM key is keyed into the carrier. View Quote View All Quotes View All Quotes Originally Posted By RDTCU: Originally Posted By backbencher: Don't say no machining capability. You have a drill & a Dremel, no? It would seem your fancy gas key would bolt right on to a Bootleg carrier. Their website is back up: https://bootleginc.com/ That would give you the most control, and you can always have a pencil barrel to drop weight later. It won't just bolt up. The ZM key is keyed into the carrier. Could an ARFCOMer with a mill in South Carolina mill a Bootleg carrier so the ZM key would fit? |
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Death to quislings.
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