New Army "Caliber Configuration Study"

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  • stanc
    Banned
    • Apr 2011
    • 3430

    Originally posted by HANKA View Post
    Thanks, Stan, for taking the time to generate the data points. So, worst case, our carbine is still almost going neck-and-neck with their MMG?
    Yeah. Much better than I expected. It looks to me like a 65G LMG would be quite capable of going up against a PKM, even without a super-streamlined bullet.
    Something went awry at the 700-yard mark on your drop data?
    No, the numbers are correct. I guess I really should've changed the column heading from "Drop" to "Trajectory." I ran it using 1000 yards as the zeroing distance, in order to show the height above ground the bullets reach en route to 1000 yards.

    Comment

    • stanc
      Banned
      • Apr 2011
      • 3430

      Was curious what difference there'd be to use G7 instead of G1 BC's, so I re-ran the tables. Makes little difference in trajectory and wind drift, but definitely affects velocity.

      6.5 Grendel LMG: 110gr Barnes banded solid (0.232 G7 BC) @ 2550 fps from 16" barrel.

      7.62x54R PKM: 148gr 57-N-323S mild steel core (0.208 G7 BC) @ 2750 fps from 25.4" barrel.

      Data was generated using the online JBM Ballistics Calculator. (Traj = Trajectory)

      _______ 65G _ 762 ____ 65G _____ 762 ____ 65G _____ 762 ___ 65G __ 762
      Range _ Traj __ Traj _ Windage _ Windage _ Velocity _ Velocity
      (yd) ___ (in) __ (in) ___ (in) _____ (in) ____ (ft/s) ___ (ft/s)

      000 ____ 0.0 ___ 0.0 ___ 0.0 ____ 0.0 ____ 2550.0 __ 2750.0
      100 ___ 48.6 __ 44.9 ___ 0.8 ____ 0.8 ____ 2360.4 __ 2530.0
      200 ___ 90.9 __ 84.3 ___ 3.4 ____ 3.4 ____ 2179.1 __ 2319.9
      300 __ 125.9 _ 117.3 ___ 7.9 ____ 8.0 ____ 2006.4 __ 2120.5
      400 __ 152.3 _ 142.5 __ 14.7 ___ 14.9 ____ 1841.0 __ 1931.2
      500 __ 168.3 _ 158.3 __ 24.0 ___ 24.4 ____ 1682.3 __ 1750.6
      600 __ 172.1 _ 162.8 __ 36.2 ___ 37.0 ____ 1529.6 __ 1577.8
      700 __ 160.9 _ 153.2 __ 51.8 ___ 53.2 ____ 1383.4 __ 1412.7
      800 __ 131.5 _ 126.1 __ 71.3 ___ 73.6 ____ 1244.8 __ 1256.8
      900 ___ 79.6 __ 76.9 __ 95.4 ___ 99.0 ____ 1117.6 __ 1114.6
      1000 ___ 0.0 ___ 0.0 _ 123.9 __ 129.2 ____ 1043.0 __ 1036.0

      Energy @ 1000 yards
      65G: 266 ft-lbs
      762: 353 ft-lbs

      Comment

      • Tony Williams

        Originally posted by HANKA View Post
        Tony, perhaps I wasn't clear, but what I meant is that I'd like to postulate a 6.5 M855A1, with its two-part copper and steel construction, that exactly matches the shape or form factor of the 6.5mm 112gr GS Custom monolithic in order to preserve that bullet's BC, as nearly as possible.

        Photo concept attached.
        That bullet looks very good, John. It's simpler than the M855A1 because it doesn't include the half-jacket, but inserts the steel penetrator straight into the brass body. It looks like a half-way point between the bullets which ARDEC made for their calibre comparison tests a few years ago (which had a smaller steel element IIRC), and the RUAG HC bullets which are mostly steel penetrator with a smaller brass "shoe" around the base (see below). My only concern with these designs is the potential effect on the BC of the join between the steel and brass bits, and whether the steel tip is so easy to work to the optimum shape.



        By the way, talking about efficient Russian designs take a look at the bullet from the experimental Russian 6 x 49 Unified round - it weighed only around 5g (77 grains) - shown here next to the 5.45 x 39:



        Finally, just to illustrate the issue over bullet length and form factor, here's a selection of 5.56mm military bullets: 55 grain M193, 62 grain M855, 62 grain M855A1, 77 grain MK262. You can see the length issue with the lead-free bullets, and the fact that despite its extra length, the MK262 FF is actually no better than the M855's - it improves in long-range performance only by being heavier.

        Comment

        • BluntForceTrauma
          Administrator
          • Feb 2011
          • 3897

          Those Russian bullets are creatures of ballistic beauty!

          John
          :: 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


          • Those clever Russians, they made the 6mm bullet with the rifling grooves already pressed in. I bet that makes it go even faster!

            Comment

            • stanc
              Banned
              • Apr 2011
              • 3430

              I always did like that 6x49 round.

              Comment

              • BluntForceTrauma
                Administrator
                • Feb 2011
                • 3897

                I know you've long championed the 6mm SCC. And it is commendable that it is the one concept the Russians seemed most interested in as an alternative. What, if any, do you see as drawbacks to the concept as a replacement for both 5.56N and 7.62N?

                John
                :: 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

                  If you mean my 6mm Optimum (below), one of the drawbacks that come to mind is the same as for 6.5 Grendel and 6.5 GPC: Increased weight and size relative to 5.56 NATO.

                  Another, perhaps more important issue, is that barrel life would likely be very low.

                  Comment

                  • NugginFutz
                    Chieftain
                    • Aug 2013
                    • 2622

                    Found this AP hosted article regarding the M4 vs. the "Others". Definitely slanted against the M4.



                    A bit of interactive stuff, but still a puff piece.
                    If it's true that we are here to help others, then what exactly are the others here for?

                    Comment

                    • stanc
                      Banned
                      • Apr 2011
                      • 3430

                      Originally posted by NugginFutz View Post
                      A bit of interactive stuff, but still a puff piece.
                      And, being a 2008 article, a wee bit dated...

                      Comment

                      • BluntForceTrauma
                        Administrator
                        • Feb 2011
                        • 3897

                        Army still wants the 6.5 Grendel and still doesn't know it.

                        They want a compact, semi-auto sniper rifle. And, further, I quote: "However, advances in warfighting technology have promoted the need for increased sniping capabilities to counter constantly changing threats particularly in urban environments and at extended ranges."

                        Hmmm. . . Now who does THAT sound like?

                        High sectional density for urban penetration? Check.

                        High BC for extended ranges? Check.

                        Lightweight? Semi-auto? Need I say more?

                        It boggles my mind that the biggest no-brainer in the history of small arms is staring them in the face. Instead, "Let's extend the range by increasing weapon bulk and weight and by increasing ammunition blast and recoil."

                        John
                        :: 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

                          Perhaps if a 6.5 Grendel sniper rifle was to be demonstrated to the sniper community?

                          Better yet, let Army snipers shoot it side-by-side with a 7.62mm M110?

                          Comment

                          • NugginFutz
                            Chieftain
                            • Aug 2013
                            • 2622

                            “For those who believe, no proof is necessary. For those who don't believe, no proof is possible.” ~ Stuart Chase
                            If it's true that we are here to help others, then what exactly are the others here for?

                            Comment

                            • Guardsman26

                              I understand that the US Army's Caliber Configuration Study is now proceeding with all guns blazing if you'll forgive the metaphor. Better news is that the US Army leadership and key influencers are all behind it with the US AMU is leading from the front by providing its own new ammo proposals. Common sense has prevailed meaning that the CLAWS and LDAM programs won't materialise until the US Army has decided which calibers it wants to use in future. I sense that there is now a shared belief that 5.56mm has reached the omit of its development potential. The UK has signed a MoU with the USA and will participate in the CCS. Meanwhile, the performance of the existing Grendel round is serving as a benchmark. Exactly which calibers are being looked at is not publicly available, but you don't need the brains of an archbishop to realise that it will likely include: .250, .260, .270 and .280 (with .308 above and .223 below serving as reference calibers). Meanwhile, as H&K melts down in the wake of the G36 scandal, FNH seems to be refining both SCAR-H and Minimi Mk 3 platforms. If I were a betting man, I might lay odds on the next US Army AR being the SCAR-H in something very close to a 6.5mm Grendel. Of course, there's many a slip between cup and lip, but I tend to think that the overall configuration of the SCAR-H has created a new AR benchmark.
                              Last edited by Guest; 07-02-2014, 04:25 PM.

                              Comment

                              • stanc
                                Banned
                                • Apr 2011
                                • 3430

                                Originally posted by Guardsman26 View Post
                                I understand that the US Army's Caliber Configuration Study is now proceeding with all guns blazing if you'll forgive the metaphor. Better news is that the US Army leadership and key influencers are all behind it... The UK has signed a MoU with the USA and will participate in the CCS.
                                Nick, that's very interesting news. (Pardon the late response. Somehow I missed seeing your post before today.) I'd rather like to see the Germans get on board, too. I always thought their old 6.5x43 round and its very long ogive bullet looked quite promising.


                                Meanwhile, the performance of the existing Grendel round is serving as a benchmark. Exactly which calibers are being looked at is not publicly available, but you don't need the brains of an archbishop to realise that it will likely include: .250, .260, .270 and .280 (with .308 above and .223 below serving as reference calibers).
                                I hope .240 is also included. The Russki 6x49 may have been too high pressure, but I think the projectiles were on the right track.


                                Meanwhile, as H&K melts down in the wake of the G36 scandal, FNH seems to be refining both SCAR-H and Minimi Mk 3 platforms. If I were a betting man, I might lay odds on the next US Army AR being the SCAR-H in something very close to a 6.5mm Grendel.
                                I'd take that bet. I personally like what I've seen of the SCAR-H, but has there been any US military interest in it, outside of SOCOM?

                                Plus, it seems worth noting that the Turks have reportedly adopted an AR-10 derivative. http://www.thefirearmblog.com/blog/2...ational-rifle/

                                Comment

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