Bullet tolerances

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  • lrgrendel
    Warrior
    • Jul 2013
    • 662

    Bullet tolerances

    Was loading today for a competition tomorrow and being more anal than normal!

    AMAX 123. Noticed the length of the bullet was up to 5 thou's OFF. I was loading to 2.255 and about 1/3 out of 80 loaded came out at 2.600. I also measured from the ogive to the base and they were very consistent.

    I called Hornady and the guy said their actually tolerance was up to 17 thou's for total length of bullet and around 1 thou from the base to the ogive.

    I would be interested to hear if anyone has seen a difference like this with Berger, Sierra or Lapua bullets.

    And for the experts, at what distance shooting if any would you see a problem with a 123 AMAX being 5 thousands longer?
  • mnhntr
    Bloodstained
    • Dec 2014
    • 30

    #2
    I used to separate my bullets by ogive length and load them in those batches. The 142gr SMKs I use in my .260 very from .69 to .72. The 123gr AMAXs have similar tolerance differences as did the 140gr AMAXs. I quit doing it because I never noticed any accuracy differences.

    Comment

    • Savage Shooter
      Warrior
      • Dec 2014
      • 241

      #3
      Glad to see this thread here - I was thinking about starting one after skimming through both Vol. 1 and 2 of my new Grendel Handbooks and not seeing anything about weight sorting brass, weight sorting bullets or sorting by bearing surface of the bullets, and neck turning brass for consistent neck tension. I do most of these reloading activities for my 6.5 Creedmoor (Savage Model 12 LRP with 26" barrel), but I think that gun is more capable of taking advantage of the these "advanced" (and Pain in the A##) reloading steps. I have just started to reload for the Grendel, and was wondering if such steps in the Grendel load are a waste of time in a AR-15 platform (versus a bolt gun). Any one else experiment with these techniques and found them to not be worth the time?

      By the way Irgrendel, of my measurements of 900 Berger 140 Gr .264 HYBRID VLds, I saw two different "nodes" the bullets clumped into. The overall range for bearing surface was 0.5335 to 0.5450 with 31% of the bullets (measured in .0005 grain increments with a Mitutoyo caliper) being between 0.5335 and 0.5350 and 56.2% being in another 0.002" "window" between 0.5415 and 0.5435. So, I saw an overall spread in the bearing surface of 0.0115 inches over 900 bullets (not a small test sample!).

      I measured 197 Hornady 140 Gr AMAX (they shorted me 3 bullets out of 2 boxes) and found a RANGE of 0.6340 to 0.6500 - or a spread of 0.016". So, a bit wider than the Bergers and considerable higher than the 0.001 tolerance that the Hornady tech guy told you. (Granted, apparently he stated that tolerance was Base to Ogive and I measured the bearing surface (end of the boat tail to the ogive), which many consider to be the more important parameter. The AMAXs had three nodes over that range with 36% being between 0.6345 and 0.6365 and 50.8% between 0.6390 and 0.6410. The balance of the 197 bullets were between 0.6485 and 0.6500.

      It was interesting to note that there were no bullets outside of these "bands" - something in both companies manufacturing OR PACKAGING (if they somehow sort and combine the bullets) processes creates 2 or 3 nodes across the entire range with nothing in-between.

      Did it make a difference? For the Bergers, I loaded 5 each of the longest and 5 each of the shortest bearing surfaces and shot two groups, alternating between short and long in each group (so one group had 3 long and 2 short and the other had 2 long and 3 short). And I didn't see any real difference in group size or point of impact at 100 yards. (I can't find the targets to quote the exact group size, but I recall the "aha" moment and I am not likely to sort my next batches of bullets after I shoot through these 1100.) Mnhntr stated that he didn't notice any difference - anyone else? I sure would like to avoid the extra steps if it doesn't make a difference in a Grendel either.
      My "6.5" = 24" AA Overwatch upper 1/9 twist, NC based US Tactical lower, standard A4 6 position stock, AR Gold Trigger, JPS SCS buffer, Vortex 6-24 x 50 FFP PST with EBR-2C MOA reticle

      Comment

      • LRRPF52
        Super Moderator
        • Sep 2014
        • 8569

        #4
        I think if you have a rifle that is capable of delivering extreme accuracy, then it might make sense for you to weight sort if you are competing.

        With the open tip match bullets from Sierra, Lapua, and Berger, there are major variations in meplat geometry that some competitive shooters will uniform with tooling.

        I have such a tool from Tubbs for 6.5mm, but never ended up using it. I'm more of a practical steel blaster at distance when it comes to those things, but a shooter looking to tighten their ring count and x count will benefit from holding tight consistency with the bullets.
        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

        • lrgrendel
          Warrior
          • Jul 2013
          • 662

          #5
          Originally posted by LRRPF52 View Post
          I think if you have a rifle that is capable of delivering extreme accuracy, then it might make sense for you to weight sort if you are competing.

          With the open tip match bullets from Sierra, Lapua, and Berger, there are major variations in meplat geometry that some competitive shooters will uniform with tooling.

          I have such a tool from Tubbs for 6.5mm, but never ended up using it. I'm more of a practical steel blaster at distance when it comes to those things, but a shooter looking to tighten their ring count and x count will benefit from holding tight consistency with the bullets.
          I do NOT have a highly accurate rifle but on the other hand I would like to reduce any errors in components IF they actually affect me. I am stretching the Grendel to probably it's maximum range so to me it is critical my components are very consistent.

          Now today I was supposed to take part in a 300 yd F Class competition but the weather did not cooperate here in Central Florida. I was likely to be up against the likes of 6mm BR or something as accurate. My AR 6.5 Grendel was not really going to compete but that is not the point...

          I am not sure that weighing or measuring bullets would have helped me today but I am convinced banging some small steel targets at a 1000 yds it would.

          It is funny I measured some 6.5 123 Scenar's and some 308 175 Sierra MATCHKINGs. Very few but some had a variation of 5 thousands but not as as high a percentage as the Hornady.

          Comment

          • lrgrendel
            Warrior
            • Jul 2013
            • 662

            #6
            Originally posted by Savage Shooter View Post
            Glad to see this thread here - I was thinking about starting one after skimming through both Vol. 1 and 2 of my new Grendel Handbooks and not seeing anything about weight sorting brass, weight sorting bullets or sorting by bearing surface of the bullets, and neck turning brass for consistent neck tension. I do most of these reloading activities for my 6.5 Creedmoor (Savage Model 12 LRP with 26" barrel), but I think that gun is more capable of taking advantage of the these "advanced" (and Pain in the A##) reloading steps. I have just started to reload for the Grendel, and was wondering if such steps in the Grendel load are a waste of time in a AR-15 platform (versus a bolt gun). Any one else experiment with these techniques and found them to not be worth the time?

            By the way Irgrendel, of my measurements of 900 Berger 140 Gr .264 HYBRID VLds, I saw two different "nodes" the bullets clumped into. The overall range for bearing surface was 0.5335 to 0.5450 with 31% of the bullets (measured in .0005 grain increments with a Mitutoyo caliper) being between 0.5335 and 0.5350 and 56.2% being in another 0.002" "window" between 0.5415 and 0.5435. So, I saw an overall spread in the bearing surface of 0.0115 inches over 900 bullets (not a small test sample!).

            I measured 197 Hornady 140 Gr AMAX (they shorted me 3 bullets out of 2 boxes) and found a RANGE of 0.6340 to 0.6500 - or a spread of 0.016". So, a bit wider than the Bergers and considerable higher than the 0.001 tolerance that the Hornady tech guy told you. (Granted, apparently he stated that tolerance was Base to Ogive and I measured the bearing surface (end of the boat tail to the ogive), which many consider to be the more important parameter. The AMAXs had three nodes over that range with 36% being between 0.6345 and 0.6365 and 50.8% between 0.6390 and 0.6410. The balance of the 197 bullets were between 0.6485 and 0.6500.

            It was interesting to note that there were no bullets outside of these "bands" - something in both companies manufacturing OR PACKAGING (if they somehow sort and combine the bullets) processes creates 2 or 3 nodes across the entire range with nothing in-between.

            Did it make a difference? For the Bergers, I loaded 5 each of the longest and 5 each of the shortest bearing surfaces and shot two groups, alternating between short and long in each group (so one group had 3 long and 2 short and the other had 2 long and 3 short). And I didn't see any real difference in group size or point of impact at 100 yards. (I can't find the targets to quote the exact group size, but I recall the "aha" moment and I am not likely to sort my next batches of bullets after I shoot through these 1100.) Mnhntr stated that he didn't notice any difference - anyone else? I sure would like to avoid the extra steps if it doesn't make a difference in a Grendel either.
            Thanks for the detailed response. Please read below.

            Comment

            • LR1955
              Super Moderator
              • Mar 2011
              • 3355

              #7
              Originally posted by lrgrendel View Post
              I do NOT have a highly accurate rifle but on the other hand I would like to reduce any errors in components IF they actually affect me. I am stretching the Grendel to probably it's maximum range so to me it is critical my components are very consistent.

              Now today I was supposed to take part in a 300 yd F Class competition but the weather did not cooperate here in Central Florida. I was likely to be up against the likes of 6mm BR or something as accurate. My AR 6.5 Grendel was not really going to compete but that is not the point...

              I am not sure that weighing or measuring bullets would have helped me today but I am convinced banging some small steel targets at a 1000 yds it would.

              It is funny I measured some 6.5 123 Scenar's and some 308 175 Sierra MATCHKINGs. Very few but some had a variation of 5 thousands but not as as high a percentage as the Hornady.
              LRG:

              That small an amount will not make a bit of a difference. My suggestion to guys who are getting into competition is to find a load they like and once found, focus their time and effort on practice.

              It seems as guys get more into competition, they will go into neck turning, weighting brass, and uniforming primer pockets among other things. They will do this for a few years before they realize none of it really matters and that their time is better spent on practicing using a trusted load.

              They do realize that using the best components makes a difference so use the best components for your particular sport.

              LR1955

              Comment

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