I could use a little help with some loads.

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  • Builttoughf350
    Unwashed
    • Feb 2018
    • 7

    I could use a little help with some loads.

    Quick history on the rifle- it use to have a 18" Black Hole Weaponry barrel, now it has a 16" Alexander Arms barrel and it is usually suppressed with my AAC 7.62SDN-6 suppressor.

    I use to run 100Gr Barnes TTSX bullets with great results in the 18" 1:9 twist barrel with the bullets seated at 2.250" COAL

    The new Alexander Arms 16" barrel has a 1:7.5 twist ratio so I wanted to take advantage of that and run 120Gr bullets.

    I loaded up a batch with 120Gr A-MAX annnnnnnd... thats when my nightmare began. The bolt wasnt closing 100% and trying to manually eject the case was next to impossible without using a hammer on the charging handle. It seemed as though this new barrel does NOT like 2.250" COAL - and perhaps the bullets are hitting the lands. BUT ---- I re-seated the bullets down to 2.239 and they still prevent the bolt to close into full battery - and still require a hammer to open the charging handle.

    *** My old leftover 100Gr TTSX bullets cycle fine.
    ***Factory Hornady 123Gr SST ( 2.239" COAL) cycle fine. ***
    *** to the naked eye the reloaded 120Gr Amax loads look identical to the Factory Hornady ammo, and the caliper measures the cases pretty much identical so I dont think my dies left the reloaded cases wider than they should be.

    Any Ideas ?!?!?!?!? Ditch the 120Gr Amax bullets ? Seat the COAL even shorter ?
  • Drillboss
    Warrior
    • Jan 2015
    • 894

    #2
    My guess is you need to seat them deeper. Color a bullet with a Sharpie and see if you get any rifling marks on it.

    From my notes, I measured the 120 GMX in my chamber, and they actually gave me a COAL a touch longer than 123 gr SST's, but I never loaded and fired any. Other projects stepped in the way.

    Comment

    • Builttoughf350
      Unwashed
      • Feb 2018
      • 7

      #3
      Drillboss,

      Ive looked without much luck for info on these 120Gr Amax's for COAL and Im considering trying Barnes 120Gr TTSX with this as well,
      But I assume ill be using compressed loads for them, and would love to find a chart to go by for powder charges. Do you know of any charts for this ? The ones ive found do not list them.

      Comment

      • Builttoughf350
        Unwashed
        • Feb 2018
        • 7

        #4
        I marked two bullets with black marker and I do have a definite ring around both of the bullets that I got to jam without going into full battery. Trying to figure out how to post a pic of them.

        Comment

        • BCHunter
          Warrior
          • Jan 2018
          • 555

          #5
          Barnes site has load data on 120 ttsx in grendalhttp://www.barnesbullets.com
          Last edited by BCHunter; 02-18-2018, 10:24 PM.

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          • grayfox
            Chieftain
            • Jan 2017
            • 4295

            #6
            The 120 class bullets from Hornady have a more blunt nose profile than the 123's, so my guess would be 1 of 2 things:
            1. The new chamber needs shorter headspace... if you're using fired-brass check the datum point. New brass should not have this issue, but I mention it as you didn't say whether it's new or resized brass.
            2. Could be with the blunter ogive these pills need even shorter coal's than you've tried. I haven't personally used any 120's in order to stay away from this issue, the 123's have a more secant ogive (I think I have the right term) which is longer and sleeker.

            Anyway, best way to check for all of this is as DrillBoss says. I measure out every new chamber with unprimed, unpowdered bullet seated at a long, then shorter and shorter depths until I know what the max coal is for that bullet. Then take I take off an additional "tolerance" since pills do vary somewhat in length... Use a collet puller to remove the bullets from the cases once you've determined coal for that cartridge. Keep notes.
            I do this with just the upper and bcg, I don't use any spring force 'cause I want to have a good feel for the bullet as it goes into battery. Guide it in with fingers until it's well into the chamber area, this protects the tip etc. a bcg should be able to easily close on the casing.

            I also measure fired vs unfired datum-space (head space) on my brass so I know what that is as well. This, again, is for each chamber. So I know how far back to bump shoulders during resizing.

            Hope these ideas help you.
            "Down the floor, out the door, Go Brandon Go!!!!!"

            Comment

            • grayfox
              Chieftain
              • Jan 2017
              • 4295

              #7
              O, one more thing - the BHW barrel could well be an "LBC" style, or straight throat, single angle freebore, which again, could allow for longer coals. The AA barrel is a SAMMI throat, with a compound angle in the throat-freebore area, which could need therefore a shorter coal than you were used to. Just one more possible variable you might be encountering.
              "Down the floor, out the door, Go Brandon Go!!!!!"

              Comment

              • Lone Hunter
                Warrior
                • Jan 2017
                • 170

                #8
                You say you used a BHW barrel and then went to an AA barrel. You will have a different seating depth. Sounds like to me you need to check your headspace. Pretty sure it will be different. You need to get a Comparator to see where your bullet contacts the rifling. I have a 20" .264 LBC and a Howa 20" HB bolt action. They both have different headspace and both have different measures to the ogive. When I first started loading for the .264LBC I had the ring like you did. I had to also seat deeper and use a body die to make the headspace .003-.004 on the AR and .002 on the bolt action. That took care of my problem. If I were you I would get a Hornady Comperator and check my headspace and also get a modified case and see where my bullet was touching the lands. You can only seat so far out with magazine lengths also. It doesn't have to be a Hornady but something similar because you sure need to get some appropriate measures.
                Last edited by Lone Hunter; 02-18-2018, 10:55 PM.

                Comment

                • ricsmall
                  Warrior
                  • Sep 2014
                  • 987

                  #9
                  The 120 amax requires much shorter seating depth due to the less than ideal nose design. Seems like 2.20 was seating depth on these before the 123 amax came along. Do some searches, as there are probably numerous threads on this bullet.
                  Member since 2011, data lost in last hack attack

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                  • Builttoughf350
                    Unwashed
                    • Feb 2018
                    • 7

                    #10
                    Grayfox - the Saami / LBC threat difference makes a ton of sense as well as the blunter ogave.
                    I'd really love to try the 120gr TTSX thanks for the chart from Barnes.

                    Comment

                    • Builttoughf350
                      Unwashed
                      • Feb 2018
                      • 7

                      #11
                      And for what it's worth, if I remember right I think I ordered the AA barrel with a bolt they supplied for it but I may be wrong.

                      Comment

                      • grayfox
                        Chieftain
                        • Jan 2017
                        • 4295

                        #12
                        Using the matched bolt will ensure proper chamber sizing for AA b/c total chamber depth is measured from the "breech face" or the bolt face (the flat), and there are 2 distinct bolt face depths floating around in the Grendel world. AA IIRC has a bolt face depth of 0.136 (the real "Grendel" one IMO), whereas some mfrs use a 0.125 depth (akin to a 7.62x39 bolt face depth). Again there are several threads on this so search-fu is your friend. Sticky's too.
                        You can measure using your caliper to see which one (or ones) you have, then again make notes on them. AA's are good quality.
                        ps at one point I had 5 grendels and 2 had one headspace, 3 had a slightly shorter one. 0.003-0.004 but enough to keep some [edit: "re-sized"] cases from fully chambering.

                        SAAMI pdf info:

                        65Grendel_SAAMI_Specification.pdf
                        Last edited by grayfox; 02-19-2018, 12:07 AM. Reason: re-sized cases
                        "Down the floor, out the door, Go Brandon Go!!!!!"

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                        • grayfox
                          Chieftain
                          • Jan 2017
                          • 4295

                          #13
                          We just started a new print run of Volume I (4th Printing) and Volume II (2nd Printing). No changes were made to Volume I from the 3rd Printing, which includes the updated Western Powders data from 2014. Some slight changes were made to Volume II. We fixed a small typo on page 48 referring to figure 6.7 when it should


                          best money you'll spend on your Grendels.
                          "Down the floor, out the door, Go Brandon Go!!!!!"

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                          • Crusty
                            Warrior
                            • Dec 2017
                            • 237

                            #14
                            I use a home made OAL gauge to measure the length to the lands in my rifle with every new bullet I try, and then a comparator jaw on my calipers to measure case base to bullet ogive on loaded rounds so I know exactly how close to the lands my bullets can come. I also use a Wilson caliber gauge to check my brass, both shoulder set back and case length.

                            Of course my rifle's SA and my round fit in the chamber might be sloppy to a bolt gunner, but the principle of measuring to the ogive on the lands and the finished rounds is sound and it ensures that my bullets will fit in the chamber and not be jammed into the lands. I've found that measuring to the meplat isn't consistent, but ogive measurements are and I don't even care what the COL is as long as they fit in the mag.
                            I'll be yer Huckleberry.

                            Comment

                            • Drillboss
                              Warrior
                              • Jan 2015
                              • 894

                              #15
                              Originally posted by Builttoughf350 View Post
                              Drillboss,

                              Ive looked without much luck for info on these 120Gr Amax's for COAL and Im considering trying Barnes 120Gr TTSX with this as well,
                              But I assume ill be using compressed loads for them, and would love to find a chart to go by for powder charges. Do you know of any charts for this ? The ones ive found do not list them.
                              Lots of good info has posted since you asked this. Again, I have not yet fired a 120 GMX bullet, so what I have is generic info.

                              Hornady's data for 120-123 gr bullets includes the 120 GMX, so their loads should not be overpressured for the GMX.

                              When I bought my AA barrel, they told me they do not match bolts to barrels. Tolerance specs make them work together. If you have an AA barrel and an AA bolt, you should be fine on headspace.

                              If you don't have comparators to measure headspace and overall length, try these. Start out by making sure your sized brass will chamber and extract easily in your rifle. Keep bumping the shoulder back a little until they chamber and extract without resistance.

                              Then, drop a loaded round (or a dummy round) into your barrel with the muzzle pointed down. Next, turn it muzzle up and see if it drops free. It should. If you have to bump it to get it to fall out, you need to seat the bullet a little deeper. If it does fall free, then you aren't into the lands. Coloring the bullet should confirm this.

                              As far as powder is concerned, as always, start low and work up.

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