UTM Holdover Data

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    • #108607
      rhino11
      Participant

        I ran a drop test on UTM ammo before our recent Force on Force class in Idaho. This was using the standard “Man Marker Rounds’ and not the reduced velocity CQB rounds. Test rifle was a stock Colt 6920 (16″ / 1/7″ twist). Temperature was mid sixties. The scope: a Leupold Mark 6 with a CMR-W .5.56 reticle.

        The test protocol was to shoot groups at 10, 20, 30, 40 & 50 yards using the same forehead hold at each distance.

        For red dot shooters & those who just want something simple:
        @ 10 hold forehead & hit mouth
        @ 20 hold forehead & hit chest
        @ 30 hold forehead & hit gut
        @ 40 hold forehead & hit crotch
        @ 50 hold over head to hit crotch.

        Put even more simply: If you put your dot on the top of your target’s helmet, you will hit from contact to 50 yards. If there is any discernible crosswind at 20 yards & beyond you need to favor for it.

        For the detail oriented, drop in inches and MILS are below:
        10 yards: 3.5″ / 8 MILS (corresponds to the 800 meter reticle hash)
        20 yards: 8.5″ / 10.5 MILS (corresponds to the 900 meter reticle hash)
        30 yards: 16″ / 14 MILS.
        40 yards: 28″ / 18 MILS.
        50 yards: 41″ / 23 MILS

        There is a lot of vertical dispersion (more than 8” @ 50 yards), so bear in mind this is measuring with a micrometer, marking with a grease pencil & cutting with an ax.

        You will know your dope is pure when you hear the OPFPR yell “F*ck!” while falling over as you spring that hasty ambush in your next Force on Force training…
        Good hunting!
        D

      • #108608
        JohnnyMac
        Participant

          Well done! :good:

        • #108609
          tango
          Participant

            What zero were you using?

          • #108610
            rhino11
            Participant

              Sorry, I should have mentioned the zero: The Mark 6 is set up for a 200 meter zero, which is about 1/2″ low at 50 yards using M855 or similar.
              D

            • #108611
              tango
              Participant

                If you ever get the chance to repeat this with 100yd zero it would be great to compare. Anecdotally, some of us repeat UTM alumni over east here use 100yd zero and have agreed it works best to minimize holdover. Much more point-shoot-hit over the spread of UTM range. That’s based on hits on eachother during iterations, no real scientific method.

                Not detracting from your data, but worth noting:
                The target shoot at the beginning of class is great for each individual –
                as long as you accept the results and don’t compare yourself. The tendency sometimes is to mentally FUBAR the situation by comparing holdovers with everyone afterwards. Nobody uses the same zero so Guy-A using 25yd zero shoots next to Guy-B using 100yd zero and their holdovers are totally different. One guy’s holding sky high and the other right on the shoulders, both making center mass hits @ 25yds. Then they go do an iteration and think all their misses are UTM’s fault because they can’t agree on holdovers.

              • #108612
                rhino11
                Participant

                  “If you ever get the chance to repeat this with 100yd zero it would be great to compare.”

                  With the aid of your favorite ballistic calculator we can easily convert the data for a rifle zeroed at 100 yards.

                  If you plug in M855 type numbers (for comparable results try a G1 ballistic coefficient of .301 @ 3000 fps with a 2.7″ height above bore) with a 200 yard zero you will see that your bullet path above line of sight at 100 yards is 1.1″ (or .3 MIL). That same .3 MIL results in a 1/2″ delta between the 100 and 200 yard zeros at 50 yards, or a 1/4″ delta at 25 yards.

                  In plain English, if you prefer a 100 yard zero, add 1/2″ to the 50 yard drop data, and add 1/4″ to the drop for 20 & 30 yards. Given that the vertical dispersion of these rounds exceeds 4 MILS at 50 yards, we are approaching a debate of how many angels can dance on the head of pin.

                  Guys who use the US Army standard 300/25 yard zero can subtract .9″ from the drop table at 50 yards, and 1/2″ at 25…

                  Because the UTM rounds never cross above the line of sight until you out to around an 800 yard zero (they are going too slow), if you apply the ‘put your dot on the top of the target’s hat,’ you will always get on the torso of an exposed target out to almost 50 yards. If all you have to shoot at is the target’s helmet, then you need to apply some holdover, or you can just ‘zipper up’ on subsequent shots.

                  I hope this helps…
                  ;-)

                • #108613
                  tango
                  Participant

                    Because the UTM rounds never cross above the line of sight until you out to around an 800 yard zero (they are going too slow), if you apply the ‘put your dot on the top of the target’s hat,’ you will always get on the torso of an exposed target out to almost 50 yards. If all you have to shoot at is the target’s helmet, then you need to apply some holdover, or you can just ‘zipper up’ on subsequent shots.

                    Thanks @rhino11 So there’s almost no mathematical difference in the zeros, as long as you’re zero’d properly – interesting. Quoted above is the simplest golden technique explanation on shooting UTM.

                    The zippering technique is not unique to UTM, it’s actually a practical shooting technique for multiple weapons platforms. I would suspect point-shoot-hit mindset comes from square range stationary target type training. Cadre could explain this in great detail far better than myself, possibly an interesting idea for a longer post @firstsergeant

                  • #108614
                    rhino11
                    Participant

                      There are, of course, downsides to using techniques like ‘zippering.’ The most obvious is the risk of training scars which can carry over to the real world. You ‘own’ every round which leaves your muzzle, and the risk of fratricide or hitting innocent bystanders is significant with FMJ or M855 in urban or suburban environments (or your house).

                      One of our guys cranked 10 MILS of elevation onto his scope (giving himself a true 20 yard zero) at the beginning of Force on Force training. That way he had a true ‘point & shoot” weapon (a little high @ 10 yards, a little low at 25) out to about 25 yards. Since many of the guys in the OPFOR were wearing plates, he had an easier time hitting hips or heads than those of us who were ‘holding high and spraying.’ One important safety tip: remember to crank that 10 MILS off your scope after you are through with UTM’s, or your 1st round with live ammo is going to be really high!

                    • #108615
                      First Sergeant
                      Moderator

                        The zippering technique is not unique to UTM, it’s actually a practical shooting technique for multiple weapons platforms. I would suspect point-shoot-hit mindset comes from square range stationary target type training. Cadre could explain this in great detail far better than myself, possibly an interesting idea for a longer post

                        Explain what you mean by “point-shoot-hit mindset”.

                        As far a zippering goes, I was taught that technique in one handgun class that I took. I am not a fan off it and I don’t teach it.

                        FILO
                        Signal Out, Can You Identify
                        Je ne regrette rien
                        In Orbe Terrum Non Visi

                      • #108616
                        Max
                        Keymaster

                          This has the potetial for getting complicated. I prefer to think of UTM as a microcosm of live fire. According to this data, shooting at 50 YARDS roughly corresponds to shooting at 500 meters. With a 100 meter zero rounds center mass will inpact around the feet. David’s testing shows maybe a 3.5 foot drop at 50 YARDS.

                          Also recall that when you shoot close with live, like when we stand at 10 meters and do stream fire, due to height over bore and zero, your live rounds will go low unless you adjust. Half unconvinced that this is not also happening with UTM at 10 yards.

                          In the real world with a 100 meter zero, if you underestimate the range you will hit low and will have to adjust your strike onto the target. This is real world ‘application of fire.’ With a belt fed, you walk the rounds on. It is also applicable to wind and leading a moving target. Adjust and fire till the target goes down or out of sight.

                          So UTM is a microcosm of that. Important that ‘zippering’ does not become a training scar, but application of fire by adjusting up for longer ranges is applicable. ‘Zippering’ would also be applicable down the torso if you are hitting body armor, adjust down to belly/hips.

                          Head shots are generally not recommemded on dynamic targets, unless that is the only center mass presented to you. Head shots as security shots once the target is down. They are always alive when you get there.

                        • #108617
                          Max
                          Keymaster

                            I think the point-shoot-hit refers to the point blank zero i.e. the search for the best zero to hit out to farthest within your chosen ‘minute of man’ target, while not having to adjust for range. Hence 50/200 becoming more popular than 25/300 in a bit to utilize a flatter portion of trajectory for longer.

                            I have given reasons why I like the 100 meter zero.

                          • #108618
                            tango
                            Participant

                              The zippering technique is not unique to UTM, it’s actually a practical shooting technique for multiple weapons platforms. I would suspect point-shoot-hit mindset comes from square range stationary target type training. Cadre could explain this in great detail far better than myself, possibly an interesting idea for a longer post

                              Explain what you mean by “point-shoot-hit mindset”.

                              As far a zippering goes, I was taught that technique in one handgun class that I took. I am not a fan off it and I don’t teach it.

                              I mean thinking in terms of wherever I put the center of my crosshairs that’s exactly where my rounds go as a less-than-perfect idea. Thinking in terms of minute of man rather than 1MOA from the center of my dot torture target. I know you understand what I’m about to say, but accounting for offset between POA to POI at 10yds is different than the offset on the same rifle at 150 yds. You have to think about it a little before shooting when you’re running around trying to pick people off at various ranges. To hit the man on the other end it may take a little searching with a few shots to actually get there rather than the instant 1-shot hits you get in practice on constant distance, stationary targets. That idea applying to live as well as UTM, although obviously more weighted to UTM.

                              Is that invalid or is there something I don’t know?

                            • #108619
                              rhino11
                              Participant

                                Knowing what we know now, there should be some value in cranking on enough elevation that the UTM projectile crosses the line of sight twice without too much deviation above the line of sight. Functionally this is the same thing as a 50/200 or 25/300 yard zero, just a lot closer.

                                I cannot model this with ballistic software since I have no idea of what the ballistic coefficient is for the UTM pellets. The next time I have a few rounds and a blue bolt available I will give it a go.

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