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Posted: 7/4/2026 8:49:59 PM EDT
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Over the past several months, I’ve been approaching the Lima Six belt-fed system much like a modern SOPMOD Block I/II enhancement program, identifying areas where upgrades and ergonomic refinements could further improve the platform. A few immediate focus areas became apparent early on: the charging handle, telescoping feed stud, folding front sight/bayonet lug assembly, and an improved feed tray capable of retaining linked ammunition during loading. The goal has been to enhance shooter ergonomics, handling, and field usability without compromising reliability or adding unnecessary complexity. The charging handle assembly became the first area of development. Drawing inspiration from proven legacy belt-fed systems such as the FN M249, Stoner 86, and Russian PKM, I began prototyping several redesigned charging handles. After multiple revisions and plenty of help from Harvey, I finalized a few concepts that I believe improve manipulation while also giving the platform a more purposeful and refined appearance. I’ve printed Stoner 86, M249, and PKM inspired variants for preliminary fitment and handling evaluation. Fitment has been excellent, and the designs are nearly finalized. The next step will be sourcing a machine shop to manufacture them from 7075 aluminum with a black anodized finish. I also explored an FN M240inspired charging handle configuration but ultimately decided against it, as the longer handle had a greater tendency to snag on gear. Here’s a look at the printed prototypes installed on the Lima Six:     The next component I’ve been developing is a telescoping feed stud that allows the top cover to close with the bolt forward, similar to the FightLite MCR system. I’ve printed the initial prototype and am currently working to determine the ideal spring rate, one that provides enough force for the plunger to extend reliably while also keeping it fully engaged as it reciprocates with the bolt during cycling. There’s still a significant amount of testing ahead, but this is the initial concept.  I’ve also designed a feed tray that helps retain the ammunition belt during loading, eliminating the need for belt holders or a second hand. This is accomplished through a spring-loaded feed-assist pawl that pivots above the feed tray to keep the belt in position. I believe this adds meaningful functionality while making the loading process more user friendly. Like the other upgrades, this component is being designed as a true drop-in replacement.     The final component currently under development is a folding front sight/bayonet lug assembly. The bayonet lug base has already been printed, and I’m continuing to refine the front sight design. My current plan is to pair it with the LPA rear sight, as it closely mimics the M249 rear sight, although I may also adapt it to work with the Occam rear sight. The bayonet locks securely into the lug, which has been a promising milestone.   If you have any recommendations regarding the designs, materials, or manufacturing process or if there's an upgrade you're particularly looking forward to, leave a comment and let me know. |
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It’s great to see all the innovations that the Lima Six project has inspired. The fact that Harvey actively encourages and helps everyone is very unique. |
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An armed populace is governed. An unarmed populace is ruled.
An armed populace is governed. An unarmed populace is ruled.
| If I incorporate a shell deflector and heat shield, this is going to be one bulky charging handle. I believe that if you are running a belt fed, you have to wear proper PPE. M249 had Skelton cuts already into them which I hope will shed heat a bit more than the standard L6 CH. |
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Originally Posted By Silverbear_51: If you could incorporate a shell deflector into your charging handle design, it would be a distinct improvement for the southpaws out here. Also a heat shield so you could manipulate the bolt without having to wear gloves. Pull an ejector  LIMA SIX Tips and Tricks #8: Left Handed Shooters (ejector removal) |
https://www.limasix.com
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This is awesome! I have shared a lot of these ideas, but input very little effort into it, as life calls me other directions. Another part to look at is a carry handle. Using an M249 handle, or an M60E4 handle on a pic rail mount would be ideal. I have a sling swivel loop that I need to put aa handle onto that would work perfectly, but I don't know about survivability. I have some other ideas if you are in SoCal, I can meet or discuss them, I'm still in Ca part time. I would buy all of those upgrades! Furthermore, I have a friend with a foundry and machine shop in Los Angeles. He is interested in doing firearm related parts if that is near you. |
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I have not developed a carry handle because I am planning to use the RRH handguard which already has a dedicated carry handle. I believe there is already a couple of picatinny carry handles on the market. I’m in the SoCal area. A casting wouldn’t make sense because the low quantity couldn’t justify the price of making the tooling. I will be shooting some emails over the weekend to some machine shops to determine prices and see where it goes. If you have a recommendation, let me know. |
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LA, USA
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By changing the current design of the front sight bases vertical tang to 50% of the folding leafs lower width and the two lower ears of the folding tang should to 25% of the lower width will increase stability and wear resistance. Exponential stiffness of the sight base with near grunt proof front sight bend resistance will also be gained. Position retention: suggest using positive manual latching to retain sight in both folded and un folded positions. Ideally the latch, pin or plunger mating surfaces would be tapered to match the engagement surfaces thereby eliminating wobble and rattle. Advice: look at as many charging handles as possible for inspiration. Non reciprocating is highly desirable, folding would be preferred. |
| Waiting on machine quotes right now. My first run will be 25 units each of the m249 and Stoner and 10 for the PKM style. I won’t take preorders since I want to guarantee parts on hand. I am currently ordering a few springs to test in the reciprocating feed stud which after, I will send to RRH, Harvey, and a few others to T&E. The front sight will take some time as I haven’t gathered all the dimensions. The feed tray will need to be T&Ed too. |
| I have looked at a lot of different style of charging handles and I believe these are what most people would like to see. Some people are trying to mimic the M249 while others want a bigger handle to grasp. I’d love to do a folding handle like the RPD or the FAL but this is a reciprocating system and it’s more added parts that I haven’t designed. In regards to non reciprocating, the receiver would have to be redesigned or parts needs to be designed so that it can be retrofitted onto the side, I have explored the retrofit option and it seems possible but there would need to be machining done to execute this. |
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| I have thought about developing a universal base with interchangeable handles but never thought about using a non conductive material. From everyone’s review of the L6, the handle can get super hot and will probably melt most plastics and woods. I have made Skelton cuts to the handles so that heat can shed off of it. |
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I don’t think that there will be enough interest to justify that handle. I can see a g10/g11 sleeve type handle. *****UPDATE****** I have determined the spring I will be using for the reciprocating feed stud. I will make a sample of 5-10 to have T&E done. I will ask Harvey what material might be best for the feed stud but so far, everything looks promising. I have finalized on a machine shop and will have first article sent to me in a month. |
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***** UPDATE ****** First article finalized. Machining for handles will begin this week. Design for reciprocating feed stud will be finalized this week and possibly a quote of T&E run of 10. New design included grease grooves but won’t finalize this version till after testing. Harvey has come in with the material rec for hardened 4140 which is what the T&E and production versions will be made of. |
| Most definitely. I will releasing all updates here and my instagram page: Viridium Designs. Currently setting up everything. Reciprocating feed stud is still in first article production. I believe dremel smith is releasing his version but I have my reservations on it due to some of the unsupported portions of the part. The good thing about my feed stud is that it is chunky but the caveat is minimal clearing will need to be done which I will demonstrate and offer the service for a small fee. |
| First article for the reciprocating feed stud is finalized and some slight design changes have been made. First article for handles are in my possession and production of those will be finalized by end of the upcoming week. Next product will be the flip folding sight/bayo combo that will cowitness with LPA sight. |
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