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LIMA SEVEN Belt Fed 308 Official Build Thread (Page 2 of 3)
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Originally Posted By LimaSix: Can you provide some links? If SR25 pattern is easier to convert, that is very relevant information. |
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Originally Posted By KavonTN: Came to say this. Originally Posted By KavonTN: Originally Posted By FlatlandBusa: Co-developing this with inoculum so a dedicated lower is available at launch would be nice for those of us who don't have an AR10 already. Came to say this. Working on it! We have some cool ideas for it, waiting for Harvey to get further along, for now we will sketch some things up! Lucky for us, our engineer has a long long LONG history of large and magnum framed AR based products. He is also a Spring wizard as well! ETA: We are going to keep things grounded on the design of this though, The IGM7 has a ton of 3D surfacing on it, and the cost to produce has been crazy. Most shops want nothing to do with something that has so much surfacing on it. So for the .308 version, we will keep it looking good, but also make sure we keep it more manufacturable. "Costco Hotdog" as Harvey says. |
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Originally Posted By TZLVredmist: Working on it! We have some cool ideas for it, waiting for Harvey to get further along, for now we will sketch some things up! Lucky for us, our engineer has a long long LONG history of large and magnum framed AR based products. He is also a Spring wizard as well! ETA: We are going to keep things grounded on the design of this though, The IGM7 has a ton of 3D surfacing on it, and the cost to produce has been crazy. Most shops want nothing to do with something that has so much surfacing on it. So for the .308 version, we will keep it looking good, but also make sure we keep it more manufacturable. "Costco Hotdog" as Harvey says. If someone is going to spend 7k or whatever on the 308 upper I feel like a dedicated lower at $600-800 vs $300 isnt too crazy. But ideally the extra makes cool functionality and not JUST appearance. |
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Originally Posted By TZLVredmist: Working on it! We have some cool ideas for it, waiting for Harvey to get further along, for now we will sketch some things up! Lucky for us, our engineer has a long long LONG history of large and magnum framed AR based products. He is also a Spring wizard as well! ETA: We are going to keep things grounded on the design of this though, The IGM7 has a ton of 3D surfacing on it, and the cost to produce has been crazy. Most shops want nothing to do with something that has so much surfacing on it. So for the .308 version, we will keep it looking good, but also make sure we keep it more manufacturable. "Costco Hotdog" as Harvey says. Use 45 degree chamfers on outside contours and fillets on inside contours. It will look great and be easy to machine. |
https://www.limasix.com
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I wish we could get a FCG that provided default open bolt locking. Maybe have a two stage trigger such that stage one disengages the bolt hold open, keep pulling and it lets you drop the hammer once the bolt closes. Keep it held back and it stays in an FRT mode. Release quickly and it engages the bolt lock keeping the chamber empty until the next trigger pull. That way you could meet the ATF's closed bolt requirements but still have it function like an open bolt belt fed. |
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Originally Posted By jaqufrost: I wish we could get a FCG that provided default open bolt locking. Maybe have a two stage trigger such that stage one disengages the bolt hold open, keep pulling and it lets you drop the hammer once the bolt closes. Keep it held back and it stays in an FRT mode. Release quickly and it engages the bolt lock keeping the chamber empty until the next trigger pull. That way you could meet the ATF's closed bolt requirements but still have it function like an open bolt belt fed. Yeah, someone needs to design this. I would take a stab at it but I'm pretty slammed with the 308 developement as well as managing production on the L6. If someone doesnt come out with this in the next 6 months maybe I'll work on it. |
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| Well I’m excited for this too! Love my LimaSix and everyone that shoots it is impressed. Showed this thread to a buddy that’s interested as well and just passing on that a feed stud that retracts similar to the cloak industries upper so the top cover can close no matter the bolt position was requested. I’m not bothered by it either way, just need to start saving so I can get one of these someday too! |
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As a former owner of an RIA M60 who did MG line shoots I never swapped out a barrel in order to keep shooting. Most times I would dump a 100 round box and let it sit. There were times I would dump 300-400 rounds in a single burst and again just let it sit to cool. In my experience only the most hardcore guys or guys who were trained in the military or who really cared about prolonging barrel life swapped them out at some predetermined round count. While the idea of a QD barrel might be nice for perhaps different barrel lengths, I do not see it being necessary for how most end users would use this system. Personally, I never saw the appeal of a semi belt fed but now with FRT's it would be totally different. I am most curious where the cook off point of a LIMA 7 would be with an FRT at a ROF of 600 or 700 RPM. If I recall correctly the cook off point for a standard LIMA 6 was just north of 200 rounds with an FRT. How many more rounds before cook off does a heat sink get you and is the number worth the added cost? |
I need to make the top cover latch stronger on the L7, and there is not enough space on the standard mag release button for a stronger spring. So I'm going to make a perfectly scaled up clone of the mag release button. It's gonna be pretty cool I think 
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https://www.limasix.com
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Outstanding. The non-reciprocating right sided cocking handle it a fantastic idea. Nutsacks are important on a Beltfed imo. I’d consider a dedicated lower that incorporates a bottom ejection port but still has provisions for a nutsack. Shorten the magwell, bottom is solid for the nutsack retention groove, add an angle ejection port out the right side of the magwell with a case deflector inside to control ejection. QD barrel is a necessity IMO. It’s better to have it than not. Maybe design something like the FN Evolys with a single or even the LMT pattern dual retention cross bolts. That way it’s a fast swap, but not necessarily QD and keeps the weight down. |
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Originally Posted By CaveCreek: Thought I'd jump in here. In regard to a heat sink maybe I missed something. I have had a few Shrikes/MCR's since 2000 and whatever, probably 8 or so. At one time I picked up 2 Gen 5 with the heat sink. I understood Aries abandoned that when they supposedly discovered it held heat in on the removable barrel due to lack of heat transfer from barrel to aluminum heat sink. Heat paste like on a computer chip would help but not viable on a removable barrel. Any thoughts on this? Did I go down a rabbit hole? Anyhow I removed the heat sink from my systems. Love the Lima 6!!!! Picked up the builders kit and have had zero issues over 1000 rounds the first days. Only issue was mine, getting the gas porting to the place where I can run weak Tula Steel 55 gr up to SS109 62 gr. Using Hoffman's trigger kicker which by the way has perfect timing. Look up Lima6 video on timing and also Google M16 timing if you've been getting lit hits. Ive built and worked on, improved, HK Belt feds since the late 80's and am a big BeltFed lover! It's great Harold and his team are building systems that don't take 50 mods to run right like my experience with the Shrike/MCR. Plus he is keeping the cost of spares and parts down so you don't have to have the Military's budget to keep you belts pulling. This time we are in with all the great ideas is reminiscent of the 80's and 90's where people used their brain cells instead of simply copying others work verbatim. I'm beginning to like this era we're in! The Lima 6 is kicking the competition with their business model of affordability and soon, parts availability plus customer service is the best I've seen. I can only assume this is Ralph Sr. Great to see you here. |
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Originally Posted By LimaSix: I need to make the top cover latch stronger on the L7, and there is not enough space on the standard mag release button for a stronger spring. So I'm going to make a perfectly scaled up clone of the mag release button. It's gonna be pretty cool I think You could always use nested dual springs. |
Middleofnowhere, Nebraska
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Originally Posted By FlatlandBusa: You could always use nested dual springs. There is not really enough room for that. I already tried using a heavier gauge spring, and the coils bottom out before you can push the button all the way. The top cover needs to be extremely secure on the 308, there is a lot more violence happening in there. The original 1919 machine guns had an issue where the top covers were popping open during firing, and they had to retrofit heavier springs on all of them to fix the issue. A retrofitted 1919A4 latch is extremely tight, to the point that you usually need two hands to pop them open. On the A6 they completely changed the latch design to make it easier to open while still being secure. The other thing is, the standard button will be painful to push if the spring is extremely stiff. Point is, I'm not taking any chances on this. I really want to nail the design on the first prototype to keep the project on schedule. |
https://www.limasix.com
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Originally Posted By LimaSix: There is not really enough room for that. I already tried using a heavier gauge spring, and the coils bottom out before you can push the button all the way. The top cover needs to be extremely secure on the 308, there is a lot more violence happening in there. The original 1919 machine guns had an issue where the top covers were popping open during firing, and they had to retrofit heavier springs on all of them to fix the issue. A retrofitted 1919A4 latch is extremely tight, to the point that you usually need two hands to pop them open. On the A6 they completely changed the latch design to make it easier to open while still being secure. The other thing is, the standard button will be painful to push if the spring is extremely stiff. Point is, I'm not taking any chances on this. I really want to nail the design on the first prototype to keep the project on schedule. Good points. |
Middleofnowhere, Nebraska
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Originally Posted By EnablerNo1: Could the 240 top cover latch design be used? The M240 top cover latch is a steel part that engages with another steel part. We have a steel latch part that needs to engage with an aluminum receiver. So we need a larger contact area to prevent the latch from damaging the receiver over time. |
https://www.limasix.com
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Originally Posted By EnablerNo1: Outstanding. The non-reciprocating right sided cocking handle it a fantastic idea. Nutsacks are important on a Beltfed imo. I’d consider a dedicated lower that incorporates a bottom ejection port but still has provisions for a nutsack. Shorten the magwell, bottom is solid for the nutsack retention groove, add an angle ejection port out the right side of the magwell with a case deflector inside to control ejection. QD barrel is a necessity IMO. It’s better to have it than not. Maybe design something like the FN Evolys with a single or even the LMT pattern dual retention cross bolts. That way it’s a fast swap, but not necessarily QD and keeps the weight down.  And it will have safety wire on the angle eject "Cartridge" bolts because safety wire is frickin' cool and we want that wear portion replaceable. |
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Originally Posted By JestersHK: I could see a dedicated lower here that has an angled or curved ejection shute with the bottom dove tail remaining intact for attaching a nutsack. Bottom ejection is interesting but I'm guessing good reason for it? Non reciprocating charging handle means no forward assist. No forward assist means we should use a single ejector (for more reliable chambering). Single ejector will be much more reliable in a down eject configuration. Also, no ejection port on the right side means that side of the gun will be much better sealed from debris. |
https://www.limasix.com
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Originally Posted By jaqufrost: I wish we could get a FCG that provided default open bolt locking. Maybe have a two stage trigger such that stage one disengages the bolt hold open, keep pulling and it lets you drop the hammer once the bolt closes. Keep it held back and it stays in an FRT mode. Release quickly and it engages the bolt lock keeping the chamber empty until the next trigger pull. That way you could meet the ATF's closed bolt requirements but still have it function like an open bolt belt fed. Holy crap, that would be incredible. ETA: Can you please incorporate a mechanism to keep the top cover from slamming down with gravity and make so it can be closed regardless of where the bolt is? This is pretty exciting, thank you for working on this! |
| I would like to cast my vote for the upper to be slant cut (Knights SR25/ Armalite/ LMT/ LaRue, etc.). Slant cut uppers will also fit on DPMS LR308 style radius cut lowers, there will just be a slight gap. And in this age of 3D printers, a plug similar to the L6 one could probably be used, for those who want to put this on a PSA, DPMS, or Aero lower. |
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Super interested. If youre not going with QD barrels, will different barrel lengths be a possibility? I dont think I saw anyone ask but some kind of a tripod adapter would be nice. The M2 or M122 or similar seems like a good option or even a mount for the German AA tripods which are still reasonably priced |
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Originally Posted By CTM1: As a former owner of an RIA M60 who did MG line shoots I never swapped out a barrel in order to keep shooting. Most times I would dump a 100 round box and let it sit. There were times I would dump 300-400 rounds in a single burst and again just let it sit to cool. In my experience only the most hardcore guys or guys who were trained in the military or who really cared about prolonging barrel life swapped them out at some predetermined round count. While the idea of a QD barrel might be nice for perhaps different barrel lengths, I do not see it being necessary for how most end users would use this system. Personally, I never saw the appeal of a semi belt fed but now with FRT's it would be totally different. I am most curious where the cook off point of a LIMA 7 would be with an FRT at a ROF of 600 or 700 RPM. If I recall correctly the cook off point for a standard LIMA 6 was just north of 200 rounds with an FRT. How many more rounds before cook off does a heat sink get you and is the number worth the added cost? Make the barrel heavy enough and it’s more than 400 rnds. The 21 fires from a closed bolt at a higher RoF than an AR is gonna. It does fine. Attached File |
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Originally Posted By fordkicksass: I'm guessing no since this will be ejecting downward through the magwell and therefore subject to those dimensional limitations, but I have to ask is there any possibility this will have a constant recoil system? |
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Originally Posted By fordkicksass: I'm guessing no since this will be ejecting downward through the magwell and therefore subject to those dimensional limitations, but I have to ask is there any possibility this will have a constant recoil system? It will have a stretched receiver like the lima six, but with the extra energy of the 308 I doubt you'll be able to reliably tune it to prevent the carrier from bottoming out in the buffer tube. |
https://www.limasix.com
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Originally Posted By Jmolden87: I would like to cast my vote for the upper to be slant cut (Knights SR25/ Armalite/ LMT/ LaRue, etc.). Slant cut uppers will also fit on DPMS LR308 style radius cut lowers, there will just be a slight gap. And in this age of 3D printers, a plug similar to the L6 one could probably be used, for those who want to put this on a PSA, DPMS, or Aero lower. I agree with this. The KAC/LMT/Armalite slant cut is what the industry standard should be for the large frame AR. |
| If you don’t offer the QD barrel, is there any chance you’d go with a LMT MWS/MRP type barrel retention, so barrels are easily swapped just not quick detach? That would also be a nice addition to the L6. That would make it similar to the FN Evolys. |
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Originally Posted By EnablerNo1: If you don’t offer the QD barrel, is there any chance you’d go with a LMT MWS/MRP type barrel retention, so barrels are easily swapped just not quick detach? That would also be a nice addition to the L6. That would make it similar to the FN Evolys. Actually that’s a really good idea. Their standard weight barrels are about as heavy as the HK21 barrels too. I can snap some comparison pictures tomorrow. Don’t hurt that I have two MWS’s…so I wouldn’t be offended if you went with that receiver cut. |
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Originally Posted By EnablerNo1: I agree with this. The KAC/LMT/Armalite slant cut is what the industry standard should be for the large frame AR. Originally Posted By EnablerNo1: Originally Posted By Jmolden87: I would like to cast my vote for the upper to be slant cut (Knights SR25/ Armalite/ LMT/ LaRue, etc.). Slant cut uppers will also fit on DPMS LR308 style radius cut lowers, there will just be a slight gap. And in this age of 3D printers, a plug similar to the L6 one could probably be used, for those who want to put this on a PSA, DPMS, or Aero lower. I agree with this. The KAC/LMT/Armalite slant cut is what the industry standard should be for the large frame AR. And DoD has a bunch of slant cut lowers from M110s, and soon the Mk24s. If this upper is well received maybe you could have some adopted by SOCOM. One can dream! |
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Originally Posted By cms81586: They’re all semi auto. Originally Posted By cms81586: Originally Posted By Jmolden87: And DoD has a bunch of slant cut lowers from M110s, and soon the Mk24s. If this upper is well received maybe you could have some adopted by SOCOM. One can dream! They’re all semi auto. Ahh. Well not the Mk24 / MRGG-A. Plus, a drill bit and jig could fix that on the M110 |
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Originally Posted By AFSOC: Maybe a Lima 50 next? Just sayin... Attached File |
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Originally Posted By cms81586: Actually that’s a really good idea. Their standard weight barrels are about as heavy as the HK21 barrels too. I can snap some comparison pictures tomorrow. Don’t hurt that I have two MWS’s…so I wouldn’t be offended if you went with that receiver cut. Pretty easy to add a collar to a standard barrel to make it MWS compatible. D Wilson offers this service. |
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Originally Posted By EnablerNo1: I agree with this. The KAC/LMT/Armalite slant cut is what the industry standard should be for the large frame AR. "Should be" and "are" are very different perspectives of reality. As it stands the DPMS pattern is almost the defacto standard relative to market share and accessibility. I am not saying one is definitively better than the other, just that slant cut lowers are fading into irrelevance for everyone except cloners. Shoot, even PSA has thrown their hat in for round cut... |
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Originally Posted By LimaSix: There is not really enough room for that. I already tried using a heavier gauge spring, and the coils bottom out before you can push the button all the way. The top cover needs to be extremely secure on the 308, there is a lot more violence happening in there. The original 1919 machine guns had an issue where the top covers were popping open during firing, and they had to retrofit heavier springs on all of them to fix the issue. A retrofitted 1919A4 latch is extremely tight, to the point that you usually need two hands to pop them open. On the A6 they completely changed the latch design to make it easier to open while still being secure. The other thing is, the standard button will be painful to push if the spring is extremely stiff. Point is, I'm not taking any chances on this. I really want to nail the design on the first prototype to keep the project on schedule. Could you cam it shut with a handle instead of a button maybe? |
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I love this! Just like the L6, I'll be in in the ground floor for this one. I'm disappointed regarding the build kit, as I like things configured my way, and that's just that. Like I prefer deep SDM style flutes as opposed to fins. All the "demands" for quick change barrels is a bit over stated. I have carried an M249 and never had an absolute need to die the barrel change. That being said, I have turned barrels on 60E4s, 240s and M2s into glow sticks. But for this application I'm more interested in the maneuverability and man portable automatic rifle type application. Harvey, The answer to making it nutsack compatible is easy. Copy the 60E4 style hanger, and also allow ears for the canvas 762 bags. Most people are not going to have Capcom boxes. Attached File |
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Originally Posted By ABabyEater: "Should be" and "are" are very different perspectives of reality. As it stands the DPMS pattern is almost the defacto standard relative to market share and accessibility. I am not saying one is definitively better than the other, just that slant cut lowers are fading into irrelevance for everyone except cloners. Shoot, even PSA has thrown their hat in for round cut... Yet all of the quality/reliable/ actual hard use and combat proven large frame AR’s use the slant cut. |
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Originally Posted By cms81586: Yet all of the quality/reliable/ actual hard use and combat proven large frame AR’s use the slant cut. This. Who cares what PSA and other lower tier manufacturers use. Most buyers are likely going to use a purpose built lower receiver, not a stripped DPMS cut lower. Slant cut SR25 spec is the way to go IMO. Add in a 3D printed spacer for use with DPMS pattern lowers. Doing it this way allows compatibility with both SR25 slant cut and DPMS. It opens the market up to more buyers. |
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Originally Posted By EnablerNo1: Who cares what PSA and other lower tier manufacturers use. Pretty sure this exact "who cares about the poors" type attitude is exactly what/why a massive hole in the market was formed that allowed L6 to come in and sweep an incredible amount of sales... Just saying, this kind of elitism is a great way to drive people away. Now am I intending and willing to spend a ton on a belt fed 7.62 (for both the gun, and feeding it)? Sure, but that is because I am understanding of the upfront costs and looking at developed advantages in one way or another, not because I think that it should be "muh KAC, muh LMT, who cares about market availablity." And this is coming from someone who does own DD, LMT, etc. |
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Originally Posted By ABabyEater: Pretty sure this exact "who cares about the poors" type attitude is exactly what/why a massive hole in the market was formed that allowed L6 to come in and sweep an incredible amount of sales... Just saying, this kind of elitism is a great way to drive people away. Now am I intending and willing to spend a ton on a belt fed 7.62 (for both the gun, and feeding it)? Sure, but that is because I am understanding of the upfront costs and looking at developed advantages in one way or another, not because I think that it should be "muh KAC, muh LMT, who cares about market availablity." And this is coming from someone who does own DD, LMT, etc. For a 5.56 AR it doesn’t matter. Lower selection does matter for a large frame. There is no official standard or TDP for large frame AR’s. The best you’ll do is LMT/KAC. It’s not elitism. It’s about choosing a lower that is suitable and high quality. LMT lowers are the only current market large frame AR rifles designed for full auto use too. Do I care what pattern they choose? No. The L7 is one I’m probably not buying because those bases are already covered for me. But if they want to give the most flexibility, it’s the best option. |
LIMA SEVEN Belt Fed 308 Official Build Thread (Page 2 of 3)
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