Grendel LMG

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  • stanc
    Banned
    • Apr 2011
    • 3430

    Originally posted by sharky47 View Post
    Hey guys - so the picture of the 6.5G on the RPD belt is mine - they do fit great!

    Since that picture was taken, I did receive my MK46 semi from MGA - and I have even built a second gun, the only closed bolt semi auto SAW-K. The SAW-K is a form-1'd SBR now as well.

    I have been busy doing a bunch of work on the SAW, including designing/prototyping/and patenting a 300 BLK conversion barrel with a really trick secondary gas system that allows subs to work correctly. That was in partnership with US MGA.

    Anyway - I am currently working on adapting an RPD feed tray and top cover to the SAW - which if successful, will unlock 7.62x39/6.5G/9x39 - and any other cartridge that will fit on that belt. I am working with Green Mountain barrels and PTG and tooling up so I can make 9x39 ammo/dies/barrels, plan on using the 300BLK tech to make that round also run in the SAW.

    I already have a barrel and bolt made for 6.5G - soon as I get the RPD parts adapted, I can test it!

    Stay tuned.....
    Roger that. I've been pleading for years for anybody to make a belt-fed Grendel.
    It's good to see there's finally someone who has both the means and motivation.

    Hey, by chance have you checked MGA 6.8 links compatibility with the 6.5 case?

    Comment

    • Texas
      Chieftain
      • Jun 2016
      • 1230

      Has any consideration been given to the NEGEV by IMI which is currently chambered in 5.56X45 and 7.62X51. The weapon is similar to the M249 but also features a safe/semi-auto/full-auto. the 7.62 version could easily be converted to Grendel and still use AR15 style magazines in a pinch.

      Comment

      • sharky47
        Unwashed
        • Nov 2017
        • 9

        Doing it with an RPD is super easy - it's just a legacy system. But all the parts are sized correctly since the parent cartridge is the same.

        M249 takes some more doing since you have to figure out what/which belt/link system you want to make/use. There's really only once choice for off the shelf, and it's the non-disentigrating RPD belt. Tooling cost to make new disintegrating links is very expensive - but then stupid cheap to churn them out.

        Comment

        • BluntForceTrauma
          Administrator
          • Feb 2011
          • 3897

          Good article HERE questioning the whole premise of a belt-fed SAW.

          Actually made sense to me, looking at it from an angle I hadn't thought about.
          :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

          :: I Drank the Water :: Revelation 21:6 ::

          Comment

          • sharky47
            Unwashed
            • Nov 2017
            • 9

            The links that MGA made for the 6.8 could probably be stretched just a hair the same way we stretched M27 links for 5.45 (which worked well). I have some of those links - but I am pretty sure they went through few more iterations since then, I need to call them and get some of the newest ones to play with.

            But then you have to mod the feed tray a bit, no big deal - but you really need to increase the height between the feed tray and the top cover since you made the cartridge "fatter". Then you need to change the geometry of the feed lever for the increase in belt pitch forced by the increase cartridge diameter.

            This is why I am kit-bashing an RPD onto my SAW, much faster fabrication time so I can get shooting and prove a concept. As a civilian shooter - I am also fine with non-disintegrating belts, much easier to recover.

            Comment

            • stanc
              Banned
              • Apr 2011
              • 3430

              Originally posted by sharky47 View Post
              The links that MGA made for the 6.8 could probably be stretched just a hair the same way we stretched M27 links for 5.45 (which worked well).
              Yeah, I'd also think that MGA M68 links could be stretched enough to fit the 6.5 Grendel case, since I was able to press a 6.5 Grendel round into 6mm SAW links for the photo below.




              Originally posted by sharky47 View Post
              But then you have to mod the feed tray a bit, no big deal - but you really need to increase the height between the feed tray and the top cover since you made the cartridge "fatter". Then you need to change the geometry of the feed lever for the increase in belt pitch forced by the increase cartridge diameter.
              Feed tray mods: Due to the minimal cartridge shoulder protrusion in front of the link, wouldn't it be necessary to reconfigure the cartridge stop to have a squared-off, lower-left corner, as shown by the red "L" in the photo above? Wouldn't the links be likely to hang up on such a sharp corner?

              Top cover mods: Is there enough case shoulder (on 6.5 Grendel) extending in front of the links for the front feed pawl to push against? Compare shoulder extension of 6.5 Grendel (above) to that of 5.56 (below).


              Originally posted by sharky47 View Post
              This is why I am kit-bashing an RPD onto my SAW, much faster fabrication time so I can get shooting and prove a concept.
              What concept do you want to prove?



              P.S. I am surprised that 5.45x39 reportedly worked well in (stretched) M27 links. Because the base-to-shoulder dimension of 5.45x39 is little greater than on 6.5 Grendel, I would've expected you to encounter the same issues with the cartridge stop and feed pawls as I noted above. Did you have these issues, and if so, how did you deal with them?

              Last edited by stanc; 12-04-2017, 11:01 PM.

              Comment

              • sharky47
                Unwashed
                • Nov 2017
                • 9

                Ideally - you would make a link that was shorter front to back so that more of the case body protruded above the link and you could make your cartridge stop longer towards the back of the gun.

                On the 5.45 - I am going off of what MGA told me, I made them a barrel and modified a bolt/extractor for them and they shot it. I do have a barrel core made up for myself, but I have yet to populate it and shoot it.

                The concept I am proving for myself is just to make a SAW kit that runs on RPD belts and all the ammo that will fit into it.......including 9x39 - tooling for which is just starting to arrive.

                Comment

                • stanc
                  Banned
                  • Apr 2011
                  • 3430

                  Originally posted by sharky47 View Post
                  Ideally - you would make a link that was shorter front to back so that more of the case body protruded above the link and you could make your cartridge stop longer towards the back of the gun.
                  Yup. My concern is if the link can be shortened enough to properly fit the 6.5 Grendel case, and still have the needed strength and flexibility.

                  Originally posted by sharky47 View Post
                  The concept I am proving for myself is just to make a SAW kit that runs on RPD belts and all the ammo that will fit into it.......including 9x39...
                  Cool. I've long wondered if the RPD belt -- which was developed for the highly-tapered 7.62x39 case -- will give reliable operation with the relatively straight-walled 6.5 Grendel case.

                  Comment

                  • stanc
                    Banned
                    • Apr 2011
                    • 3430

                    Originally posted by BluntForceTrauma View Post
                    Good article HERE questioning the whole premise of a belt-fed SAW.
                    Hmm. Calling the belt-fed SAW a "failure" seems a bit of an overreach, considering how many armies use them.
                    I read the article, and must say I find some of it not only badly flawed, but some even dishonest. For instance:

                    -------

                    "[The SAW] burdens the squad with (literally) thousands of rounds of extra ammunition needed just to feed the two belt-feds. In the Army’s [rifle squad], each rifleman carries the same 7 magazine loadout, but on top of that they carry 200 round belts for the SAW..."

                    If the seven riflemen in the squad each carry a 200-round belt of SAW ammo, that totals to 1400 rounds, not the "thousands of rounds" claimed by the author.

                    -------

                    "In the video below, a USAF JTAC engages the enemy with a 7.62mm Mk. 48 machine gun, a close relative of the Minimi. Note the large amount of downtime of the weapon during reloading, and how difficult it is for the gunner administer the weapon by himself in combat."



                    This is blatant dishonesty. The author uses a 7.62mm LMG being reloaded with loose belts of ammo that are twice as heavy per round as 5.56mm ammo.
                    Compare to 5.56mm SAW reloading using 100-rd and 200-rd "nutsacks":




                    -------

                    "A magazine-fed automatic rifle, on the other hand, may be either based on and share parts with the infantry rifle, as in the Russian RPK, or the infantry rifle itself may serve both functions, as the M16A1 did prior to the M249’s introduction."

                    IIRC, the M16A1 rifle proved inadequate in the automatic rifle role, one of the reasons it was superseded by the M249 machine gun.

                    -------

                    "...the significantly higher accuracy of a closed-bolt automatic rifle gives similar effectiveness to the belt-fed, open-bolt SAW, while using far less ammunition."

                    The automatic rifle's "significantly higher accuracy" would seem of little value in suppressing an enemy who cannot be seen due to effective use of cover or concealment.

                    -------

                    "Although [the SAW] is capable of prodigious firepower, it sacrifices key characteristics of individual weapons to achieve it, and in doing so becomes something that is neither fish nor fowl. It is too heavy, cumbersome, and finicky to be a good individual weapon, and its caliber is too small to serve as a very good crew-served machine gun. Therefore it exists in a space where it is neither one nor the other."

                    The SAW is not meant to be a crew-served weapon. It is intended to be an individual weapon.

                    Perhaps what should be done is not to replace a poorly-designed SAW with an inadequate IAR, but with a much better SAW.
                    Last edited by stanc; 12-05-2017, 03:46 AM.

                    Comment

                    • HowaGrendel
                      Bloodstained
                      • Sep 2017
                      • 99

                      I carried a shorty SAW in Afghanistan 2010-2011 and it was the most reliable, NON-accurate weapon I ever shot.....lol.....no need for sights.....just point in general direction and start moving it around till you got close or hit something....

                      Comment

                      • BluntForceTrauma
                        Administrator
                        • Feb 2011
                        • 3897

                        Article may be flawed, but DID get me thinking. What is the proper premise for a squad level belt-fed?

                        Going back to WWII, isn't it true the MG34/42 was acknowledged as the primary killing machine, and the bolt-action rifles were basically support?

                        How does that change in the era of assault rifles/automatic rifles with full-auto fire? Does one need a burst longer than 30 rounds? Mag changes are quick. Even if one has a belt, machine gunners are taught to use short bursts, right?

                        So if we don't need a 200-round belt because we never use 200-round bursts, what's the downside to lesser on-board capacity?

                        Is the only advantage of a dedicated LMG a quick-change barrel? Pretty sure that can also be done in an IAR.

                        I don't think of the USMC as those willing to give up firepower superiority, and yet they're dropping the SAW in favor of the IAR. (Or are they also keeping their SAWs? I could be mistaken.)

                        Why do we need a belt-fed SAW in the age of full-auto capable individual weapons?
                        :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

                        :: I Drank the Water :: Revelation 21:6 ::

                        Comment

                        • stanc
                          Banned
                          • Apr 2011
                          • 3430

                          Unusually long bursts may be deemed necessary for suppressive fire when the exact position of the enemy is unknown. See the video in post #166 for an example.

                          Mag changes in military combat are not nearly as quick as the speed reloads seen in civilian competition. I'd post a video example, but don't have time right now.

                          Several decades ago, the infantry squad was equipped solely with full-auto capable M16A1 rifles. It was considered inadequate, and the belt-fed M249 was fielded.

                          Comment

                          • BluntForceTrauma
                            Administrator
                            • Feb 2011
                            • 3897

                            Originally posted by stanc View Post
                            full-auto capable M16A1 rifles. It was considered inadequate, and the belt-fed M249 was fielded.
                            Fair enough. But I can't buy in to the concept until I fully understand WHY.

                            It's possible there was something flawed with the M16A1 rifles themselves, rather than the concept of being belt-less.
                            :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

                            :: I Drank the Water :: Revelation 21:6 ::

                            Comment

                            • stanc
                              Banned
                              • Apr 2011
                              • 3430

                              Originally posted by BluntForceTrauma View Post
                              Fair enough. But I can't buy in to the concept until I fully understand WHY.
                              John, I can't provide the info you seem to want. Perhaps Paul can tell you, since he has considerable knowledge in this area.

                              Originally posted by BluntForceTrauma View Post
                              It's possible there was something flawed with the M16A1 rifles themselves, rather than the concept of being belt-less.
                              It isn't unique to the M16A1. Offhand, I can't think of any army that equips the rifle squad with assault rifles only.

                              Everyone I know of has a squad auto, either mag-fed IAR or belt-fed LMG.

                              Comment

                              • BluntForceTrauma
                                Administrator
                                • Feb 2011
                                • 3897

                                Originally posted by stanc View Post
                                Everyone I know of has a squad auto, either mag-fed IAR or belt-fed LMG.
                                Just cuz everyone's doing it the way everyone else has always done it doesn't make it smart.

                                Still want to know WHY.

                                And what's the real difference between an IAR and an AR. Heavy barrel? That's it?

                                Somebody please justify belt-fed in a modern infantry squad in 2017. "Everybody else does it" is not a justification.

                                "Well, you really need 200 rounds on-board for those scenarios when you need to do a 200-round burst." THAT'S a justification. Not a very good one, but at least it's an attempt.

                                Or, "Mag changes every 30 rounds slows weapon too much and puts unit at tactical disadvantage."

                                Or, "Need physically heavier weapon for less round dispersion at range."

                                Somebody please think through the fundamental premise and articulate it.
                                :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

                                :: I Drank the Water :: Revelation 21:6 ::

                                Comment

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