I did a comparison 120 SMK vs 123 SMK vs 123 AMAX

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  • I did a comparison 120 SMK vs 123 SMK vs 123 AMAX

    Since I'm beginning to reload with 8208, I decided to do some checking if I should decide to single load my Grendel for more precise competition shooting. I found a few interesting (at least to me) items while doing research. I used my AA Hunter upper as the test bed.

    120 SMK-
    Bullet length ~1.181"
    OAL to Lands- 2.236"
    Ogive to Lands- 1.736"

    123 SMK-
    Bullet Length ~1.291"
    OAL to Lands- 2.323"
    Ogive to Lands- 1.720"

    123 AMAX-
    Bullet length ~1.236"
    OAL to Lands- 2.282"
    Ogive to Lands- 1.710"

    What I took away from this-
    1- The shortest bullet had the shortest OAL to the lands, but also is bluntest with a tip to ogive of .5 (120 SMK)
    2- The 123 SMK is 0.055" longer than the 123 AMAX
    3- The OAL to lands on the 123 SMK and the 123 AMAX is a difference of 0.041" (In favor of the 123 SMK)
    4- But, the overall difference between the Ogive to lands of the 123 SMK and 123 AMAX is only 0.010" (The 123 SMK hits the lands slightly longer)
    So, it will be interesting to see how they stack up when I load some rounds 0.010" off the lands and see what happens.

    I am just an average guy reloading ammo and this may not mean much in the big picture, but I found it interesting. If my data conclusions are incorrect, please correct for me.
    Last edited by Guest; 08-28-2011, 05:21 PM.

  • #2
    I appreciate the effort and the info.

    Comment


    • #3
      Nice job, good measurements. Will any of those lengths that run into the lands fit in an AR magazine? I think, (not that far into it yet), but I think your mag will be your length constraint, not the lands. I'm starting my loads at the longest I think will run in my mags & working from there. I know they are clear of the lands so there will be a "jump". Off the top of my head, I'm thinking that is 2.226". There is a slight variation in lengths loading with the redding dies due to variations in actual ogive of the bullet but I'm trying to keep total length under that number. Nothing worse than having a bullet drag in the mag when you need it to feed.

      MLM

      Comment


      • #4
        I did the same measurements in my AA 16" tactical. In the chamber the SMK measured .104 longer than the AMAX, to where the oglive meets the Lands (1.797SMK vs 1.693AMAX). The Total cartridge length of the SMK in chamber was 2.295 vs the AMAX at 2.265. The interesting thing is when you load them both to Mag length 2.260, the AMAX is .020 longer to the oglive than the SMK. Less jump to the lands.

        Comment

        • LR1955
          Super Moderator
          • Mar 2011
          • 3355

          #5
          Originally posted by RStewart View Post
          Since I'm beginning to reload with 8208, I decided to do some checking if I should decide to single load my Grendel for more precise competition shooting. I found a few interesting (at least to me) items while doing research. I used my AA Hunter upper as the test bed.

          120 SMK-
          Bullet length ~1.181"
          OAL to Lands- 2.236"
          Ogive to Lands- 1.736"

          123 SMK-
          Bullet Length ~1.291"
          OAL to Lands- 2.323"
          Ogive to Lands- 1.720"

          123 AMAX-
          Bullet length ~1.236"
          OAL to Lands- 2.282"
          Ogive to Lands- 1.710"

          What I took away from this-
          1- The shortest bullet had the shortest OAL to the lands, but also is bluntest with a tip to ogive of .5 (120 SMK)
          2- The 123 SMK is 0.055" longer than the 123 AMAX
          3- The OAL to lands on the 123 SMK and the 123 AMAX is a difference of 0.041" (In favor of the 123 SMK)
          4- But, the overall difference between the Ogive to lands of the 123 SMK and 123 AMAX is only 0.010" (The 123 SMK hits the lands slightly longer)
          So, it will be interesting to see how they stack up when I load some rounds 0.010" off the lands and see what happens.

          I am just an average guy reloading ammo and this may not mean much in the big picture, but I found it interesting. If my data conclusions are incorrect, please correct for me.
          RS:

          OK....but how does this relate to the type of consistent precision you are requiring?

          Tangent ogive bullets tend to shoot more consistently from any rifle and gas blasters particularly as they are much less sensitive to jump. That's why I have a saying that if your Grendel blaster won't shoot a 120 Sierra, chances are it won't shoot anything.

          The 123 Sierra is a decent bullet from a bolt gun. Hard seat and hot load. Never messed with the 123 AMAX so I don't know but the guys on this forum claim it is outstanding and apparently isn't as sensitive to jump as the 123 Sierra.

          If you are going to shoot High Power at the real ranges, you will have problems at 300 and 600 if you have winds. It won't matter what bullet you use, either. So, choose the most consistent one you can find and be prepared to crank windage every time you see the slightest bit of shift.

          LR55

          Comment


          • #6
            There is no real motive behind this experiment other than fact-finding. Since everyone at one time or another has mentioned all of these and I have all 3, thought it would be a good chance to size them up.

            Mag length would not be a good comparison, so I wanted to see where to load as related to the lands. I already have shot High Power several times at "real ranges" (not sure about that one). Shooting High Power requires the 200 and 300 yards loads to be mag length, but 600 slow fire is single load. So this would be a 600 yard load.

            Once I check these out at 100, I will recheck the most consistent at 600 yards. I am already a F-TR shooter using a .223 bolt, so I know a little about reading wind and it's affect on bullets. Not being rude, just pointing out I do have some knowledge of the subject to rely on.
            Last edited by Guest; 08-29-2011, 02:16 AM.

            Comment

            • burnsome
              Warrior
              • Jun 2011
              • 132

              #7
              thanks for that info OP. I had a 123AMAX factory load stick in my chamber the other day in my rifle. loaded up a couple more and sure enuff', am getting some bullets that are just touching the rifling ahead of the chamber. Wolf ammo does not do this so i guess in my particular chamber, the Hornady loads are touching the lands pretty tight. the gun shoots them great with no other signs of chamber pressure or messed up brass. only issues is unloading an unfired round after chambering. i need to do some measurements on my chamber and see how much interference i'm getting.
              Last edited by burnsome; 08-29-2011, 02:31 AM.

              Comment


              • #8
                Originally posted by steel89 View Post
                I did the same measurements in my AA 16" tactical. In the chamber the SMK measured .104 longer than the AMAX, to where the oglive meets the Lands (1.797SMK vs 1.693AMAX). The Total cartridge length of the SMK in chamber was 2.295 vs the AMAX at 2.265. The interesting thing is when you load them both to Mag length 2.260, the AMAX is .020 longer to the oglive than the SMK. Less jump to the lands.

                That's why I checked all in the same rifle. Throats on rifles can vary and so each person can come up with something different in their respective rifles.
                Example: in my bolt .223 I was loading to 2.460" to be .010" off the lands with a PacNor barrel. I recently rebarreled with a Bartlein. I now have to load to 2.410" to be the same .010" off the lands.
                I'm going to load up some mag length and when I do I think I will find a very similar finding as you did.

                Comment


                • #9
                  Originally posted by mlmiller1 View Post
                  Nice job, good measurements. Will any of those lengths that run into the lands fit in an AR magazine? I think, (not that far into it yet), but I think your mag will be your length constraint, not the lands. I'm starting my loads at the longest I think will run in my mags & working from there. I know they are clear of the lands so there will be a "jump". Off the top of my head, I'm thinking that is 2.226". There is a slight variation in lengths loading with the redding dies due to variations in actual ogive of the bullet but I'm trying to keep total length under that number. Nothing worse than having a bullet drag in the mag when you need it to feed.

                  MLM
                  The 120 SMK would fit in a mag at 2.236", but I have found the 120 SMK's shoot best for me at 2.220" and the 123 SMK and 123 AMAX are too long to fit in the mag. The max I have loaded 123 SMK's to is 2.255." YMMV

                  Rick

                  Comment

                  • LR1955
                    Super Moderator
                    • Mar 2011
                    • 3355

                    #10
                    Originally posted by RStewart View Post
                    There is no real motive behind this experiment other than fact-finding. Since everyone at one time or another has mentioned all of these and I have all 3, thought it would be a good chance to size them up.

                    Mag length would not be a good comparison, so I wanted to see where to load as related to the lands. I already have shot High Power several times at "real ranges" (not sure about that one). Shooting High Power requires the 200 and 300 yards loads to be mag length, but 600 slow fire is single load. So this would be a 600 yard load.

                    Once I check these out at 100, I will recheck the most consistent at 600 yards. I am already a F-TR shooter using a .223 bolt, so I know a little about reading wind and it's affect on bullets. Not being rude, just pointing out I do have some knowledge of the subject to rely on.
                    RS:

                    Are you going to use the Grendel for High Power? Been there, done that, immediately dropped 15 - 20 points and never got them back. The wind blew the bullets around too much and holding elevation became a problem at 600. Went to a 6 mm AR and picked back up those points on the first match, plus a few more, and never looked back. Although I won't shoot a Grendel in High Power simply because there are tens of more effective cartridges out there, I still shoot it in practice periodically just to exercise my wind doping ability and to have some fun.

                    As and edit to this, the problems I encountered could well have been due to the use of the various ball powders that were our only real choice a few years ago. Unless you wanted to lose another hundred or two hundred feet per second by using Varget. So, I used TAC, 2520, and a few other common ball powders for the Grendel and lost points in a dramatic way. I used Varget and H-4895 for the 6 AR as the ball powders I tried (TAC / 2520) did not perform and had no problems what so ever across a wide spectrum of temperatures.

                    So, it could well have been the difference between ball powders and how they act in varying temperatures and extruded powders. Could well be that the 8208 XBR may be the key to success with the cartridge in varying environmental conditions.

                    Not sure how else to put it in terms of real verses reduced range shooting. I know that you probably have more reduced courses than where I live simply because of range availability. Not to be rude about it, just don't know of any other term to use. I would think the Grendel would be relatively competitive for reduced courses at 100 and 200 and even 300 providing the winds are consistent.

                    LR1955
                    Last edited by LR1955; 08-29-2011, 12:24 PM.

                    Comment


                    • #11
                      Originally posted by LR1955 View Post
                      RS:

                      Are you going to use the Grendel for High Power? Been there, done that, immediately dropped 15 - 20 points and never got them back. The wind blew the bullets around too much and holding elevation became a problem at 600. Went to a 6 mm AR and picked back up those points on the first match, plus a few more, and never looked back. Although I won't shoot a Grendel in High Power simply because there are tens of more effective cartridges out there, I still shoot it in practice periodically just to exercise my wind doping ability and to have some fun.

                      Not sure how else to put it in terms of real verses reduced range shooting. I know that you probably have more reduced courses than where I live simply because of range availability. Not to be rude about it, just don't know of any other term to use. I would think the Grendel would be relatively competitive for reduced courses at 100 and 200 and even 300 providing the winds are consistent.

                      LR1955
                      LR-

                      I'm not planning to shoot High Power with it, as like you said, there are other more suitable cartridges. I have a match AR in .223 that I shoot in High Power and have used a service rifle.

                      Thanks for clarifying the reduced range versus true distance part for me (I see what you were alluding to now). I have shot reduced range High Power matches at 200 yards and they are quite different than shooting at a true 300 and 600 yard distance.

                      I have shot my Grendel in a couple of Field Precision matches. I am looking for that combination that works best in it. Since the FPR matches are not NRA sanctioned, I can play around and tweak to my hearts content without interferring with my F-TR classification. It also has a second duty as my deer rifle.

                      As for wind and the effect on bullets, I absolutely agree. There's nothing like sending a 80 grain .223 round downrange 600 yards and getting the wind and mirage reading right and seeing an X or 10 score come up. I must be getting better at it, as my last few matches, I have won my division or placed 2nd overall. Not bad against a bunch of .308's launching them 168's and 175's. I just have to work harder.

                      Good shootin'

                      Rick

                      Comment

                      • LR1955
                        Super Moderator
                        • Mar 2011
                        • 3355

                        #12
                        Originally posted by RStewart View Post
                        I have shot my Grendel in a couple of Field Precision matches. I am looking for that combination that works best in it. Since the FPR matches are not NRA sanctioned, I can play around and tweak to my hearts content without interferring with my F-TR classification. It also has a second duty as my deer rifle.

                        As for wind and the effect on bullets, I absolutely agree. There's nothing like sending a 80 grain .223 round downrange 600 yards and getting the wind and mirage reading right and seeing an X or 10 score come up. I must be getting better at it, as my last few matches, I have won my division or placed 2nd overall. Not bad against a bunch of .308's launching them 168's and 175's. I just have to work harder. Rick
                        Rick:

                        I was wondering about the F Class thing as a Grendel isn't considered a service cartridge. Got it now.

                        You mean people who are serious about High Power are still shooting that obsolete .308 over the course? I haven't seen anyone shoot that cartridge over the course for years now. A decent service cartridge but when the .260 came on the scene, the .308's disappeared within a year. Same thing happened when the AR-15 became High Power capable. Within a year you didn't see a single M-14 on the line anymore.

                        Personally, I would shoot the old 190 load at 600 and just accept the blasting on my shoulder. Never found the 175's to be particularly consistent. Did find the 168's to be very consistent to 600 but absolutely lousy in the wind.

                        Man, you want to learn to dope winds? Shoot the .308 with the 168 grain Match Kings -- or a Grendel with any of the 120 or 123's.

                        All in good fun. Can't afford to shoot a .308 anymore so am glad I picked up several thousand 155's and 168's when they were affordable.

                        LR55

                        Comment

                        • bwaites
                          Moderator
                          • Mar 2011
                          • 4445

                          #13
                          Originally posted by LR1955 View Post
                          Rick:

                          You mean people who are serious about High Power are still shooting that obsolete .308 over the course? I haven't seen anyone shoot that cartridge over the course for years now. A decent service cartridge but when the .260 came on the scene, the .308's disappeared within a year. Same thing happened when the AR-15 became High Power capable. Within a year you didn't see a single M-14 on the line anymore.

                          Personally, I would shoot the old 190 load at 600 and just accept the blasting on my shoulder. Never found the 175's to be particularly consistent. Did find the 168's to be very consistent to 600 but absolutely lousy in the wind.

                          Man, you want to learn to dope winds? Shoot the .308 with the 168 grain Match Kings -- or a Grendel with any of the 120 or 123's.

                          All in good fun. Can't afford to shoot a .308 anymore so am glad I picked up several thousand 155's and 168's when they were affordable.

                          LR55
                          If I remember right, I think he shoots .223 80 grain bullets in FT/R against the .308's, LR1955.

                          I don't think you can do anything but shoot them single, so across the course matches you would only be able to shoot them in the slow fire portion, right?

                          He shoots the Grendel in Field Precision Rifle, (sometimes people seem to be calling it Field Tactical Rifle, I've noticed.) Its a new game that is basically "run what you brung", and the Grendel works well because of the low recoil, good accuracy. Being able to spot your own shots is an advantage.
                          Last edited by bwaites; 08-29-2011, 08:49 PM.

                          Comment


                          • #14
                            I dont shoot the G in any NRA sanctioned meets.

                            There are still a couple of guys lugging NM M-14's around, but most now shoot .223 Service Rifle, match .223 AR's and Tubbs-style rifles.

                            I don't see me transferring into the F-Open class anytime soon as I can't afford that type of equipment. So, I'll stick with my trusty Remmy 700 in F-TR and give those other guys fits. Lol!

                            Rick

                            Comment


                            • #15
                              Originally posted by bwaites View Post
                              If I remember right, I think he shoots .223 80 grain bullets in FT/R against the .308's, LR1955.

                              I don't think you can do anything but shoot them single, so across the course matches you would only be able to shoot them in the slow fire portion, right?

                              He shoots the Grendel in Field Precision Rifle, (sometimes people seem to be calling it Field Tactical Rifle, I've noticed.) Its a new game that is basically "run what you brung", and the Grendel works well because of the low recoil, good accuracy. Being able to spot your own shots is an advantage.
                              Thanks, Bill. That pretty well sums up what I do.

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