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MCX: Generation 3/SPEAR LT (Page 45 of 47)
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Some guy made a 3d printed gas valve for the MCX I'm nervous to post here among some big names that I have a lot of respect for, but here goes. I've been working over the last several years to design a four position, tunable valve to replace that of the Sig MCX. I call it the Optimized MCX Enhanced Gas Attenuation Valve (the OMEGA Valve). Is it redundant to use "optimized" and "enhanced" in the same name? You bet, but this is America and I wanted it to be called the OMEGA Valve. Anyway, it's a patent pending design that uses slotted ports to delay the gas from entering the expansion chamber of the valve, therefore delaying the unlocking of the weapon. It also utilizes SCAR gas jet screws to vent excess gas out through the distal end. It's manufactured via DMLS out of 17-4 stainless steel by MK Machining, and is coated with a hexagonal boron nitride coating by RT Coating Solutions. It works very well. The example I always like to throw out: the full-size Polonium 5.56. I love the Polonium, you love the Polonium, most of us can agree that the Polo is an excellent performer... but that traditional technology lends itself to higher back pressure, which would typically necessitate tuning on an AR-15 to achieve the most enjoyable experience with it. What could you do to an MCX to tune for it? Nothing, you just take the port pop to the face like a champ and tell yourself it's awesome because you're a Sig guy and it's "supposed to be that way." Maybe shop around and spend a bunch of money to get all the different Sig valves that come with the different barrels. Or you can use an OMEGA Valve in Position 1 with a 1.20mm jet screw and experience an entirely different system. Brass kicks gently out to the side, the recoil is softer, and the bolt unlock time is increased to the point that your ears are no longer ringing after a single shot from ejection port signature, and all becomes right in the world... I'm very proud of it. I have no idea if it works in the 5.5" or 7.75" Rattler 5.56 barrels, but I have tried it in every other configuration across all three generations. Who am I, I'm nobody, I just like guns and silencers. This was going to just be a passion project for myself, but I was talked into trying to do something with it and here we are. I'm nearing completion on a 300BLK model (Mod. 2), and have plans to hit 308 if this goes well. J. Bennett Designs OMEGA Valve Mod. 1, data table on the website. Thank you.  |
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Originally Posted By JK-919: Some guy made a 3d printed gas valve for the MCX I'm nervous to post here among some big names that I have a lot of respect for, but here goes. I've been working over the last several years to design a four position, tunable valve to replace that of the Sig MCX. I call it the Optimized MCX Enhanced Gas Attenuation Valve (the OMEGA Valve). Is it redundant to use "optimized" and "enhanced" in the same name? You bet, but this is America and I wanted it to be called the OMEGA Valve. Anyway, it's a patent pending design that uses slotted ports to delay the gas from entering the expansion chamber of the valve, therefore delaying the unlocking of the weapon. It also utilizes SCAR gas jet screws to vent excess gas out through the distal end. It's manufactured via DMLS out of 17-4 stainless steel by MK Machining, and is coated with a hexagonal boron nitride coating by RT Coating Solutions. It works very well. The example I always like to throw out: the full-size Polonium 5.56. I love the Polonium, you love the Polonium, most of us can agree that the Polo is an excellent performer... but that traditional technology lends itself to higher back pressure, which would typically necessitate tuning on an AR-15 to achieve the most enjoyable experience with it. What could you do to an MCX to tune for it? Nothing, you just take the port pop to the face like a champ and tell yourself it's awesome because you're a Sig guy and it's "supposed to be that way." Maybe shop around and spend a bunch of money to get all the different Sig valves that come with the different barrels. Or you can use an OMEGA Valve in Position 1 with a 1.20mm jet screw and experience an entirely different system. Brass kicks gently out to the side, the recoil is softer, and the bolt unlock time is increased to the point that your ears are no longer ringing after a single shot from ejection port signature, and all becomes right in the world... I'm very proud of it. I have no idea if it works in the 5.5" or 7.75" Rattler 5.56 barrels, but I have tried it in every other configuration across all three generations. Who am I, I'm nobody, I just like guns and silencers. This was going to just be a passion project for myself, but I was talked into trying to do something with it and here we are. I'm nearing completion on a 300BLK model (Mod. 2), and have plans to hit 308 if this goes well. J. Bennett Designs OMEGA Valve Mod. 1, data table on the website. Thank you. https://preview.redd.it/adjustable-gas-valve-for-the-sig-mcx-v0-tysnkb964lze1.jpeg?width=640&crop=smart&auto=webp&s=cccc34ac17b65c86cb71bb226ae3713b2fb2cf60 Looks amazing. Can't wait to see them in the wild. |
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Thank you! Mod. 1 (5.56) is currently on backorder. I wanted to re-up when my stock got to like 5 left and then I made a Reddit post and they were all gone. I have submitted my order to my manufacturer and more are on the way! Your 11.5" will love it, that's the barrel that I spent my of my time testing. What silencer (if any) are you running with it? Mod. 1 will also work to some degree in the 7.62x39 11.5" barrel, probably the 16" as well. PMC Bronze worked well anyway. This is purely serendipitous, Mod. 1 was 100% developed with 5.56 in mind. Mod. 2 (300BLK) is coming soon. 308 is a different story. Bigger gun, bigger parts, totally different geometry. It is 100% on my list of things that I want to do, but I am a one-man-band and I'm new, so Mod. 1 and 2 need to do well so I can acquire a 308 to work with. That being said, I've had various customers send me barrels, uppers, and even silencers to borrow and test with. If any 308 users are up for letting me borrow their barrel for about two weeks to take some measurements and 3D print some models to test fit, please reach out. I obviously would not be putting any rounds through it, and getting those measurements ahead of time would accelerate the Mod. 3 (308) timeline dramatically and solve a lot of problems that you guys are having a lot faster. If anyone has any questions, please feel free to reply here, or contact me through my website: jbddesigns.com You can also follow my instagrams at AudioGungineer and jbennettdesigns for updates, test footage, etc. Thanks! |
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I got mine the other day. Will get it put in today or tomorrow. I'm using an 11.5 5.56 with a Surefire RC3 and an FRT. ETA: Shot it today, was pretty neat but I'm not sure I notice a huge difference with the RC3 as far as gas in the face goes. I was surprised about how much gas vents vertically while shooting it without the handguard on. The brass ejection was a little better/ It would lock back sometimes on the 2nd position (not enough to eject the spent case) but every time with the 3rd position. I may look for some gas jets and see if that helps some more. Installation was pretty easy, just take the old one out and put the new one in. I had to depress the plunger to get the new valve in but did not have to press it to get it to move between positions. I would say it was a little more than finger tight and while I could do it without a tool, using a punch or bullet tip helped a lot. I probably could have done it without taking the handguard off but I wanted to see how it all fit together better. I haven't taken the handguard off since I got the NGAL so I guess the piston was due for a cleaning. The FRT had one light primer strike / bolt bounce(?) on the 4th position.       
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''Hokey religions and ancient weapons are no match for a good blaster at your side, kid.''
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That vertical gas leak is crazy to see. It's because of the hole in the top of the gas block, the factory Sig valves do it too. For your RC3, if you're getting consistent lock-back in position 3 with the solid screw, I would bet that the 1.20 jet would probably take you the rest of the way. I am currently experimenting with making my own jets at smaller diameters as well. If they're not a royal pain in my butt to make, I'll start offering them on the website. High-back pressure silencers definitely have the most noticeable difference when using the OMEGA Valve vs the factory Sig valve. With the high flow rate stuff, like your RC3, the HUXWRX silencers, etc., the design of the silencer already sort of dictates a reduced volume of gas exposure, and the OMEGA Valve is only going to help so much to improve that aspect of performance. You should still have an improved recoil impulse and ejection port sound signature as a result of the bolt unlock being delayed, when dialed in. The improved ejection port signature is also more noticeable with reduced flow rate silencers, because without the OMEGA Valve, the back pressure throws the action open really fast and hits the user with a nice fat port pop. Still, high-flow rate silencers can be dialed in to be better than with the stock valves. The light strike in position 4 could very well have been bolt bounce as you said, perhaps a consequence of a little much gas cycling the bolt pretty hard. Thank you for sharing your experience thus far, and the photos as well! |
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Wanted to add a backpack/PDW type gun to the collection. Being the certified Sig hater that I am I got a... Rattler LT in 7.62x39. Actually kind of excited for it. I thought about a CZ Bren 2 but I already have a 14" in 5.56 and don't want two of the same gun, so I got the Sig. Also love the look of the exposed gas regulator on the Rattler. 
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Originally Posted By Iccirrus: It's probably a purpose built handguard like they did for the CSAW Originally Posted By Iccirrus: Originally Posted By headlifeguard: Does anyone know which handguard the UK contract 12.5" spear LT uses? It's probably a purpose built handguard like they did for the CSAW I saw a video the other day talking about some UK SF unit's MCX's and it featured a black LT with a 12.5" but it still used the same rail as the 11.5". I kind of liked how the barrel stuck out a little bit more. |
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Originally Posted By Zeebz: Wanted to add a backpack/PDW type gun to the collection. Being the certified Sig hater that I am I got a... Rattler LT in 7.62x39. Actually kind of excited for it. I thought about a CZ Bren 2 but I already have a 14" in 5.56 and don't want two of the same gun, so I got the Sig. Also love the look of the exposed gas regulator on the Rattler. https://cdn11.bigcommerce.com/s-1kqh9qmybo/images/stencil/500x659/products/115255/229854/SSI166497__33637.1719437500.png I love mine |
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Originally Posted By Zeebz: Wanted to add a backpack/PDW type gun to the collection. Being the certified Sig hater that I am I got a... Rattler LT in 7.62x39. Actually kind of excited for it. I thought about a CZ Bren 2 but I already have a 14" in 5.56 and don't want two of the same gun, so I got the Sig. Also love the look of the exposed gas regulator on the Rattler. https://cdn11.bigcommerce.com/s-1kqh9qmybo/images/stencil/500x659/products/115255/229854/SSI166497__33637.1719437500.png All the 7.62's on sale have been super tempting. |
BikerNut:
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
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Originally Posted By Zeebz: For sure. I ended up getting it for like $1,650 all said and done. Originally Posted By Zeebz: Originally Posted By ALASKANFIRE: All the 7.62's on sale have been super tempting. For sure. I ended up getting it for like $1,650 all said and done. I think I've seen most of the configurations too even the SBR. Just the wrong time for me. I don't really want a 7.62 but a deal is a deal. |
BikerNut:
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
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Originally Posted By methical20: @coregon Any news on the 10.5" CSAW on the civilian side? Maybe it could help to distract a little bit from what's going on with the P320  Shit, I’m still waiting on a Rattler LT 5.56 barrel. What’s it been over 2 years and still no barrels or handguards for them? |
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Originally Posted By Cops66: Shit, I’m still waiting on a Rattler LT 5.56 barrel. What’s it been over 2 years and still no barrels or handguards for them? Originally Posted By Cops66: Originally Posted By methical20: @coregon Any news on the 10.5" CSAW on the civilian side? Maybe it could help to distract a little bit from what's going on with the P320 Shit, I’m still waiting on a Rattler LT 5.56 barrel. What’s it been over 2 years and still no barrels or handguards for them? @Cops66 Rattler LT 5.56 barrel. It was released a few months ago. |
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Originally Posted By GrAvril: Just need damned Lt handguard for 6.75 .300 barrel, what is the hold up I used one of these for a 6.75" 300 BLK barrel in a Virtus. It also fits the Spear LT upper receiver. It might be a little tight for some suppressor mounting choices, but plan A for Charlie suppressor backends, and the SRD762 & SRD762Ti direct thread work. 6 in. Midwest Industries Virtus Handguard |
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Thank you for the info. |
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Originally Posted By SgtKiwi: Picked up a 9" spear LT in 300BO this morning. Anyone have recommendations on a suppressor? Reliability most important. Surefire? I have a RC2-762mini on mine, reliable as a Swiss watch with good tone; its a good combo. 
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| For those who own the Spear LT in 7.62x39, what has been your experience with the reliability of fully loaded 28 round magazines (The ones they come with if you live in a free state)? If you leave them fully loaded for a month and then shoot them, are they still reliable? |
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Originally Posted By jwlaxton: For those who own the Spear LT in 7.62x39, what has been your experience with the reliability of fully loaded 28 round magazines (The ones they come with if you live in a free state)? If you leave them fully loaded for a month and then shoot them, are they still reliable? Work fine for me. I have to use “adverse” setting for cheap Russian shit. |
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Originally Posted By fullmedaljacket8: Work fine for me. I have to use “adverse” setting for cheap Russian shit. Originally Posted By fullmedaljacket8: Originally Posted By jwlaxton: For those who own the Spear LT in 7.62x39, what has been your experience with the reliability of fully loaded 28 round magazines (The ones they come with if you live in a free state)? If you leave them fully loaded for a month and then shoot them, are they still reliable? Work fine for me. I have to use “adverse” setting for cheap Russian shit. Thanks for the feedback. |
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Originally Posted By jwlaxton: For those who own the Spear LT in 7.62x39, what has been your experience with the reliability of fully loaded 28 round magazines (The ones they come with if you live in a free state)? If you leave them fully loaded for a month and then shoot them, are they still reliable? In 2018 and 2019 I ran those magazines HARD as I was almost exclusively running 7.62X39 AR platforms. I downloaded my magazines to 27 rounds as closed bolt reloads were really difficult with a full 28 rounds. I had no magazine related issues and the guns chewed through ammo. The only real "issue" with the magazines is that the steel feed lips are sharp and they absolutely destroyed a few aluminum lowers. I'd recommend a sacrificial magwell for the Spear lower. Let that take the brunt of the damage and replace as necessary. Also, for those of us that are vain. The 28 round magazines actually look pretty bitching in an AR lower. The 30 round magazines are a fucking abomination lol. |
Mike_Golf says: "You're not an ethical hunter and likely an asshole to boot."
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Originally Posted By Magsz18: In 2018 and 2019 I ran those magazines HARD as I was almost exclusively running 7.62X39 AR platforms. I downloaded my magazines to 27 rounds as closed bolt reloads were really difficult with a full 28 rounds. I had no magazine related issues and the guns chewed through ammo. The only real "issue" with the magazines is that the steel feed lips are sharp and they absolutely destroyed a few aluminum lowers. I'd recommend a sacrificial magwell for the Spear lower. Let that take the brunt of the damage and replace as necessary. Also, for those of us that are vain. The 28 round magazines actually look pretty bitching in an AR lower. The 30 round magazines are a fucking abomination lol. Originally Posted By Magsz18: Originally Posted By jwlaxton: For those who own the Spear LT in 7.62x39, what has been your experience with the reliability of fully loaded 28 round magazines (The ones they come with if you live in a free state)? If you leave them fully loaded for a month and then shoot them, are they still reliable? In 2018 and 2019 I ran those magazines HARD as I was almost exclusively running 7.62X39 AR platforms. I downloaded my magazines to 27 rounds as closed bolt reloads were really difficult with a full 28 rounds. I had no magazine related issues and the guns chewed through ammo. The only real "issue" with the magazines is that the steel feed lips are sharp and they absolutely destroyed a few aluminum lowers. I'd recommend a sacrificial magwell for the Spear lower. Let that take the brunt of the damage and replace as necessary. Also, for those of us that are vain. The 28 round magazines actually look pretty bitching in an AR lower. The 30 round magazines are a fucking abomination lol. Good Info! |
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One more data point. I ran 8 magazines during that time period. The 8 magazines were never cleaned and had over 40K rounds through them. They were pretty darned ratty towards the end but they continued to function. Cproducts/Duramag did a really good job on these. |
Mike_Golf says: "You're not an ethical hunter and likely an asshole to boot."
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Bought this a few weeks ago. Changed out the brace. Brand new Cloud Rein (on the other side, lefty) Swapped out the muzzle device today and mounted up the new can. Not even a single shot fired yet. Maybe next weekend. Attached File |
Gonads & Strife
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Originally Posted By Roadblock: @jbdDesigns Just backordered a Mod 1 valves for my SPEAR LT 11.5". Currently running a Hux Ventum 762, but I want to be able to run my RC2 on it, comfortably. Can't wait to get one of these for my SPEAR 16" 308, that bitch, ugh! Thanks so much! Just got them in yesterday and put in 12 hours overnight on the belt sander getting the OAL into spec, and tapped the holes for the screws. Just dropped them off at my gunsmith this morning to get the OD turned down to spec. Trying really hard to get them shipped to coating by Friday morning. Along with all of those and the Mod. 2 300BLK valves, I have one or two prototypes for something new that I think you'll be happy to hear more about soon :) |
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Originally Posted By jbdDesigns: Thanks so much! Just got them in yesterday and put in 12 hours overnight on the belt sander getting the OAL into spec, and tapped the holes for the screws. Just dropped them off at my gunsmith this morning to get the OD turned down to spec. Trying really hard to get them shipped to coating by Friday morning. Along with all of those and the Mod. 2 300BLK valves, I have one or two prototypes for something new that I think you'll be happy to hear more about soon :) AWW YISSS |
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Probably been detailed before but I don't feel like digging through the thread. If I got a x39 Rattler I can convert it to a rifle length MCX, correct? Just need a new barrel, bolt (of changing to 5.56/300 BLK), and the bolt needs the longer op-rod (Rattler and normal MCX rifle come with different length op-rods?)? Do I have that right? |
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Originally Posted By Zeebz: Probably been detailed before but I don't feel like digging through the thread. If I got a x39 Rattler I can convert it to a rifle length MCX, correct? Just need a new barrel, bolt (of changing to 5.56/300 BLK), and the bolt needs the longer op-rod (Rattler and normal MCX rifle come with different length op-rods?)? Do I have that right? Rattler LT already has the longer op-rod in it. You only need the barrel, bolt if changing between 556/300BLK vs X39), and possibly a handguard (unless you prefer a 16" barrel with the Rattler LT short handguard). |
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Originally Posted By jwlaxton: Rattler LT already has the longer op-rod in it. You only need the barrel, bolt if changing between 556/300BLK vs X39), and possibly a handguard (unless you prefer a 16" barrel with the Rattler LT short handguard). Originally Posted By jwlaxton: Originally Posted By Zeebz: Probably been detailed before but I don't feel like digging through the thread. If I got a x39 Rattler I can convert it to a rifle length MCX, correct? Just need a new barrel, bolt (of changing to 5.56/300 BLK), and the bolt needs the longer op-rod (Rattler and normal MCX rifle come with different length op-rods?)? Do I have that right? Rattler LT already has the longer op-rod in it. You only need the barrel, bolt if changing between 556/300BLK vs X39), and possibly a handguard (unless you prefer a 16" barrel with the Rattler LT short handguard). Not all Rattler LT setups have the longer oprod. My RSAR Rattler LT in 5.56 has the shorter Rattler length oprod. |
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Originally Posted By Zerlak: Not all Rattler LT setups have the longer oprod. My RSAR Rattler LT in 5.56 has the shorter Rattler length oprod. Originally Posted By Zerlak: Originally Posted By jwlaxton: Originally Posted By Zeebz: Probably been detailed before but I don't feel like digging through the thread. If I got a x39 Rattler I can convert it to a rifle length MCX, correct? Just need a new barrel, bolt (of changing to 5.56/300 BLK), and the bolt needs the longer op-rod (Rattler and normal MCX rifle come with different length op-rods?)? Do I have that right? Rattler LT already has the longer op-rod in it. You only need the barrel, bolt if changing between 556/300BLK vs X39), and possibly a handguard (unless you prefer a 16" barrel with the Rattler LT short handguard). Not all Rattler LT setups have the longer oprod. My RSAR Rattler LT in 5.56 has the shorter Rattler length oprod. That's interesting. Does it have the 7.75" barrel? |
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I believe the barrels always come with the op rod you need? I've been looking at picking up a few spare parts, and I see that the bolts seem to come in variants marked "CIP", and not CIP marked. Googling seems to suggest this may just represent an extra QC test to meet some Euro requirements... I was wondering if anyone knew for sure whether there is a any difference between them or reason to buy one over the other. The CIP ones appear to be a little more money. |
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Originally Posted By jwlaxton: That's interesting. Does it have the 7.75" barrel? Originally Posted By jwlaxton: Originally Posted By Zerlak: Originally Posted By jwlaxton: Originally Posted By Zeebz: Probably been detailed before but I don't feel like digging through the thread. If I got a x39 Rattler I can convert it to a rifle length MCX, correct? Just need a new barrel, bolt (of changing to 5.56/300 BLK), and the bolt needs the longer op-rod (Rattler and normal MCX rifle come with different length op-rods?)? Do I have that right? Rattler LT already has the longer op-rod in it. You only need the barrel, bolt if changing between 556/300BLK vs X39), and possibly a handguard (unless you prefer a 16" barrel with the Rattler LT short handguard). Not all Rattler LT setups have the longer oprod. My RSAR Rattler LT in 5.56 has the shorter Rattler length oprod. That's interesting. Does it have the 7.75" barrel? Yup, 7.75" 5.56 |
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Originally Posted By Zerlak: Yup, 7.75" 5.56 I'm surprised they made them for both the long and short op-rods. I have the 7.75" 7.62x39 and 5.56 barrels and both use the longer op rod. My 7.75" 5.56 has the T08 gas valve. Do you happen to know what gas valve your barrel has and what the port sizes are for the plus and minus settings? If you have the same gas valve, it may have the gas port in the same place on the barrel, and simply have a longer piston. |
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Originally Posted By jwlaxton: I'm surprised they made them for both the long and short op-rods. I have the 7.75" 7.62x39 and 5.56 barrels and both use the longer op rod. My 7.75" 5.56 has the T08 gas valve. Do you happen to know what gas valve your barrel has and what the port sizes are for the plus and minus settings? If you have the same gas valve, it may have the gas port in the same place on the barrel, and simply have a longer piston. Originally Posted By jwlaxton: Originally Posted By Zerlak: Yup, 7.75" 5.56 I'm surprised they made them for both the long and short op-rods. I have the 7.75" 7.62x39 and 5.56 barrels and both use the longer op rod. My 7.75" 5.56 has the T08 gas valve. Do you happen to know what gas valve your barrel has and what the port sizes are for the plus and minus settings? If you have the same gas valve, it may have the gas port in the same place on the barrel, and simply have a longer piston. T11 plug. I cannot provide gas port sizes, all of my tools are in Texas but I'm currently living in an extended stay in Montana while I try to get a job again in Texas.   
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Originally Posted By Zerlak: T11 plug. I cannot provide gas port sizes, all of my tools are in Texas but I'm currently living in an extended stay in Montana while I try to get a job again in Texas. https://i.imgur.com/8YJVbld.jpeg https://i.imgur.com/rIa1hRn.jpeg https://i.imgur.com/nkHWSHF.jpeg Looks like the gas port is in the same place, but with a shorter piston. 
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MCX: Generation 3/SPEAR LT (Page 45 of 47)
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