PDWs...and other small arms.

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  • Texas
    Chieftain
    • Jun 2016
    • 1230

    Originally posted by LRRPF52 View Post
    6.5 Grendel with an M855A1 projectile does have arms defeat advantage over M855A1 5.56, and will perforate the CRISAT test at 400m from a 14.5" barrel.

    Sectional density and length of projectile to depth of armor shows significant advantage to 6.5mm, as well as BC and retained impact speed or momentum at distance.

    Not saying 6.5 Grendel should be a 5.56 replacement, just something to consider.



    If one of the main objections to a new PDW cartridge is adding an additional DODIC to the system, then we really should be looking at letting 9mm and 7.62 NATO being left in the 20th Century, and maybe even 5.56 NATO.

    A smart move would be to develop a PDW cartridge that is also suitable for a good portion of the Combat Arms Duty positions that are not specifically tasked with engaging the enemy with their primary weapon unless in the defense or in an overrun scenario. Guys like key leaders, RTOs, Ammo Bearers, Assistant Machine Gunners, Forward Observers, JTACs, TAC-Ps, Stinger Gunners, Javelin Gunners, Carl Gustav Gunners, etc.

    None of them should be carrying a 9mm pistol. All of them should be carrying a small PDW that is effective out to 300m, but fits in a smaller package than 5.56 NATO, like the 6x35 KAC PDW updated with a better projectile in the form of M855A1.

    If that 6x35 PDW was dusted off with engineered propellant, a higher BC, and copper core with steel penetrator construction, you could have something that would do as well as 5.56 NATO M855A1 by making up for MV with BC, while allowing many more magazines to be carried than is currently feasible. Even 5.56 mags become more difficult to carry with out armor. I used to be able to carry a double basic load before Interceptor IOTV and SAAPI plates. Now you have man units who go with an SOP that is less than the older 210 rounds basic load for the M16/M4.

    With an improved 6x35 PDW, you could carry 1.5x as many mags as with NATO 5.56 STANAG mags, and have better terminal performance than M855, with higher hit probability than M855A1 5.56 by going with much higher BC.

    Have a dismounted cartridge mix of:

    PDW/Enhanced Infantry Rifle Cartridge for most soldiers
    DM/Light SASS 6.5mm cartridge
    6.5mm LSAT (which exceeds 7.62x54R performance)

    These would replace the aging 9mm, 5.56 NATO, and 7.62 NATO systems and all their penalties and limitations. 9mm has no place outside the wire, 7.62 NATO is too heavy with not enough juice for the squeeze, and 5.56 suffers from too long of a case with no room for ogive length to increase BC like 5.45x39 has.
    WE ARE IN VIOLENT AGREEMENT! Keeping the same demensions in the joining of the M16 upper and lower, the diameter to the upper could be increased to provide stronger webbing to the bolt/barrel lockup which would allow for higher pressures/velocities and REPLACE THE 5.56 and 7.62 which would simplify the supply chain significantly.

    Comment

    • LRRPF52
      Super Moderator
      • Sep 2014
      • 8569

      I like the lower working pressure of 6.5 Grendel and see it as a major advantage over higher pressure systems, especially in a military context looking at critical component life.

      You could still engineer a rifle around it from the start, but don't chase pressure when you have BC already. They have pushed 5.56 way too hard from the start, always wanting more, more, more, when a better case design with longer ogive length could have solved their retained momentum desires.

      BC gives you a lot of room to work with on the back end, rather than trying to milk performance out of the front.
      NRA Basic, Pistol, Rifle, Shotgun, RSO

      CCW, CQM, DM, Long Range Rifle Instructor

      6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

      www.AR15buildbox.com

      Comment

      • stanc
        Banned
        • Apr 2011
        • 3430

        Originally posted by LRRPF52 View Post
        6.5 Grendel with an M855A1 projectile does have arms defeat advantage over M855A1 5.56, and will perforate the CRISAT test at 400m from a 14.5" barrel.
        That would be great if it was 30 years ago and we were planning to defeat the thin metal plate armor then in use by the Soviets.

        But, how does it perform against current Russian ceramic armor?

        A smart move would be to develop a PDW cartridge that is also suitable for a good portion of the Combat Arms Duty positions that are not specifically tasked with engaging the enemy with their primary weapon unless in the defense or in an overrun scenario. Guys like key leaders, RTOs, Ammo Bearers, Assistant Machine Gunners, Forward Observers, JTACs, TAC-Ps, Stinger Gunners, Javelin Gunners, Carl Gustav Gunners, etc.

        None of them should be carrying a 9mm pistol. All of them should be carrying a small PDW that is effective out to 300m, but fits in a smaller package than 5.56 NATO, like the 6x35 KAC PDW updated with a better projectile in the form of M855A1.

        If that 6x35 PDW was dusted off with engineered propellant, a higher BC, and copper core with steel penetrator construction, you could have something that would do as well as 5.56 NATO M855A1 by making up for MV with BC, while allowing many more magazines to be carried than is currently feasible. Even 5.56 mags become more difficult to carry with out armor. I used to be able to carry a double basic load before Interceptor IOTV and SAAPI plates. Now you have man units who go with an SOP that is less than the older 210 rounds basic load for the M16/M4.

        With an improved 6x35 PDW, you could carry 1.5x as many mags as with NATO 5.56 STANAG mags, and have better terminal performance than M855, with higher hit probability than M855A1 5.56 by going with much higher BC.
        Unfortunately, there appears to be a number of problems with your proposal.



        1. The 6mm 65gr bullet has a lower BC than 5.56mm 62gr.

        2. If the 6mm bullet construction is changed to steel tip/copper slug, projectile weight will decrease, and BC will be even lower.

        3. In order to get your "much higher BC," it will be necessary to use a long-ogive bullet, a la 6.5 Grendel, which will increase cartridge OAL to that of 5.56 NATO, thereby permitting no reduction in magazine dimensions, or increase in number of magazines that can be carried. (Since OAL of the 6x35 TSWG cartridge is only 20% less than that of 5.56x45 NATO, I'm not sure how you figure it would be possible to fit 50% more magazines in the same area on a soldier's chest, anyway.)



        4. Such a long, streamlined projectile would also be much heavier*, which would significantly reduce muzzle velocity, adversely affecting effective range and armor penetration.

        *Steel core bullets for the 6mm Unified (below) were 77gr; for the 6mm SAW, 90gr.



        Have a dismounted cartridge mix of:

        PDW/Enhanced Infantry Rifle Cartridge for most soldiers
        DM/Light SASS 6.5mm cartridge
        6.5mm LSAT (which exceeds 7.62x54R performance)

        These would replace the aging 9mm, 5.56 NATO, and 7.62 NATO systems and all their penalties and limitations. 9mm has no place outside the wire, 7.62 NATO is too heavy with not enough juice for the squeeze, and 5.56 suffers from too long of a case with no room for ogive length to increase BC like 5.45x39 has.
        IMO, the optimum choice depends upon whether or not the capability to defeat modern hard body armor is wanted.

        If it is, then I think it'll be necessary to use a cartridge which combines a high BC (hardened steel or tungsten core) projectile and very high muzzle velocity.

        The velocity requirement pretty much calls for a return to long barrels. And the operational need for short weapons effectively mandates adoption of the bullpup concept.

        Last edited by stanc; 02-06-2017, 11:24 PM.

        Comment

        • Texas
          Chieftain
          • Jun 2016
          • 1230

          And so now we can see why there is not a fielded PDW

          Comment

          • ahillock
            Warrior
            • Jan 2016
            • 339




            SFC Gregory Wilson @ Fort Benning regarding training of combat soldier:

            "More and more soldiers now a days are using pistols than in past. So now they are carrying it as a secondary weapon in case their primary weapon goes hard down, or there is a malfunction that they can not clear themselves. They still have a pistol to go to to fight their way to a secure position or to where another rifle is, that they can get to use."

            Comment

            • yoni
              Unwashed
              • Mar 2017
              • 16

              The original question was about the military adopting a PDW for support troops.

              I have an Israeli perspective.

              I have never been in a support position, however I was in a position where I was issued a full sized M16 that I set up for urban sniping, a Colt Commando, mini Uzi and depending on the time frame a Hi Power and later a Glock.

              I also own a micro Uzi in Israel.

              In the IDF during my time the support weapon could have been a full sized Uzi in the old days, or today we are seeing Galils and M16 in the hands of support troops. A full sized M16 does not fit the idea of a PDW of most people here, but a lot of terrorist in Israeli cities have been killed by a full sized M16 in the hands of support troops travel between their duty station and home.

              We operated in either uniform or in civilian clothing in a covert manor. When covert a lot of us would carry in a bag a mini Uzi and I would a lot of times do the same thing off duty with my micro Uzi.

              I did have shootings off duty with the micro and was glad I had it plus a pistol with me.

              I will note that the micro was used when I had to go to social events such as wedding or bar mitsvah, etc. I would carry it in a back pack and it went on the floor at my feet. Much better than sitting a Colt Commando on the floor at a social event.

              When off duty I usually had the Colt commando with me and my pistol.

              I remember talking with my good friend Eugene Sockut who was twice the Chief Shooting Instructor for the IDF and he had a habit of training support troops to really shoot. He told me they never complained about what gun they were issued and were very happy to be taught to shoot better.

              In the civilian police they have used M1 Carbines and even micro Galils inthe same caliber. I remember hearing that with proper ammo the M1 carbine round has a good record over the military ball.

              In closing we tried the P90 in a trial and that round was a joke. 9mm ball put terrorist down better.

              So I think something like the B&T poly framed 9mm with proper training would be easy for the troops to carry and would do the job for 90% plus of what a support troop might need.

              Comment

              • VASCAR2
                Chieftain
                • Mar 2011
                • 6219

                Thanks for posting your perspective yoni, it's always good to hear from people with first hand experience!

                Comment

                • stanc
                  Banned
                  • Apr 2011
                  • 3430

                  PEO Soldier wants a 9mm PDW? RFI issued: http://www.thefirearmblog.com/blog/2...mpact-weapons/

                  Comment

                  • LRRPF52
                    Super Moderator
                    • Sep 2014
                    • 8569



                    Stan, I think I'm going to be more disgruntled and cynical than you if I ever reach your years...

                    This is madness.
                    NRA Basic, Pistol, Rifle, Shotgun, RSO

                    CCW, CQM, DM, Long Range Rifle Instructor

                    6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

                    www.AR15buildbox.com

                    Comment

                    • stanc
                      Banned
                      • Apr 2011
                      • 3430

                      Originally posted by LRRPF52 View Post
                      Stan, I think I'm going to be more disgruntled and cynical than you if I ever reach your years...

                      Comment

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