Berger 130 OTM Hybrid Load Workup

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  • heyyouguesswho
    Unwashed
    • Nov 2017
    • 19

    Berger 130 OTM Hybrid Load Workup

    Long time lurker, first time poster. I built my first 6.5 Grendel last winter and fired it for the first time in late February. I had been skeptical of actual results versus the ‘hype’ but quickly found out my Investement was very sound and that I was far from disappointed. I’ll brag about my rig later, this one’s for load development. Not to be redundant, but I’ve had some interesting finds over the last week (all good).

    The purpose of my build was long-range accuracy. I’d like to get respectable performance in the 800-1000 range just to see if I can do it. After reading these forums for months, last week I decided to start my very first workup. Since I’m going LR, I opted for the Berger 130 grain OTM AR Hybrid as one of my close friends has repeatedly had good luck with the Juggernauts in his 308. I chose powders based on both published load data and research from THIS SITE. To compare, I made two batches. One with BL-(c)2 and one with CFE 223. Here’s the result:

    Barrel: 24” Satern cut bull barrel and matched bolt. 1:8.75 twist.
    Conditions: 45 degrees farenheit. 1148 feet above mean sea level. Pressure: 30.01” hg
    Target: 100 Yards. Chrony at 10 feet (measured).
    All rounds seated to 2.260” (1.656” at 26 OGIVE with Bullet Comparator)
    CCI BR-4 Primers for all rounds.
    Brass is once-fired Hornady.

    BLC workup: 28.3gr, 28.6gr, 28.9gr, 29.2gr. According to Hornady’s 10th edition, the limit for 129-130 class bullets in BLC is 29.5 grains - no need to try that on day 1. I loaded FIVE at each charge. Checked each one for pressure signs and shot across a chrony recording each shot.

    28.3gr: 2241 FPS average, ES: 26fps. 1.1” center to center five shot group
    28.6gr: 2259 FPS average, ES: 22fps. 0.9” center to center five shot group
    28.9gr: 2299 FPS average, ES: 26fps. 0.5” center to center five shot group discarding a flyer (my bad!)
    29.2gr: 2321 FPS average, ES: 28fps. 0.75” center to center five shot group

    Not stellar. I’ve had better groups using the stock ‘Hornady BLack’ with 123 grain ELD-Match bullets. I’ve seen as little as 1/4 MOA out of that ammo, on one string.

    On to CFE! This is going to mirror some info in the load data listed in the sticky on this section of the forum. CFE brought a tremendous improvement in velocity. It contradicts Hornady’s load data in the ‘10th edition’ manual which shows BLC having the velocity advantage for these weights of bullet. Yes, I know the OTM Berger is a different animal and each barrel varies. But I was pleasantly surprised with the velocity. For this run I started with 29.7 grain and incremented in 0.3 grain steps until I hit 31.2 grain. Max charge (per Hornady’s book) is 31.7 grain which seemed really high for this class of bullet.

    29.7gr: 2419 FPS average, ES: 45fps. 1.2” group - not encouraging
    30.0gr: 2450 FPS average, ES: 29fps. 0.8” group. Redemption is coming!
    30.3gr: 2473 FPS average, ES: 39fps. 0.75” group. Coming into an Accuracy Node!
    30.6gr: 2496 FPS average, ES: 50fps. Threw a flyer that opened the group to 1.5”, group was around 0.8”” without the flyer included.
    30.9gr: 2532 FPS average, ES: 28fps. Small cloverleaf that had a center-to-center group of 0.3” from what I could measure! We have found a node for this barrel!
    31.2gr: 2583 FPS average, ES: 59fps. Opened up into a small ‘box’ with 0.45” centers. Also had what I perceived as a tiny bit of flattening on the primers.

    Phase 1 testing was fine. Phase 2 will be a Ladder test and I intend to do this at 300 yards.
    Last edited by heyyouguesswho; 11-21-2017, 08:59 PM.
  • heyyouguesswho
    Unwashed
    • Nov 2017
    • 19

    #2
    For the ‘phase 2’ test (ladder), I’ve created another round of loads in 0.2 grain steps. These start lower and end slightly higher than tested. I start at 29.6 grain and increment all the way to 31.4 grain of CFE 223. The stopping point on my first run was 31.2 and one of the five exhibited a slight pressure sign. I am apprehensive to fire that last round, despite data indicating 31.7 is max.

    I have also created five additional rounds at 30.9 grains (the ‘node’ discovered in round 1) which I’ll use to get this thing on target at 300 yards. I really don’t have any confirmed trajectory for this thing yet - just some data while playing with the factory Hornady Black last Spring and Summer. I will say this, the factory ammo did a nice job out to 600 but it fell apart from there.

    I’m really enjoying the CFE223 performance despite a slightly larger ES than I had hoped. Calculation of the SD’s isn’t too awful, but I’ll save that for a later time. Will see how the Ladder works out as soon as I get a ‘calm’ wind day (Northern Iowa, it’s always windy). If we get some clusters during Ladder test, I’ll put something together and try it out to 1000 Yards. According to the Ballistic tables, this should easily be possible as the transonic range is beyond 1100 at this elevation/density.

    More as I get a chance to test!

    Comment

    • heyyouguesswho
      Unwashed
      • Nov 2017
      • 19

      #3
      Also worth noting is the twist rate of my barrel versus suggested for this weight of bullet. 8.75 twist versus the recommended 8.0. At 100 there isn’t enough data to determine if we’re fully stabilized. I defer to the leaders on here; but I fear if the temps drop much lower we may throw some curveballs with my barrel. Maybe, maybe not. Experience will tell!

      Comment

      • LRRPF52
        Super Moderator
        • Sep 2014
        • 8569

        #4
        Welcome aboard.

        My experience with the Bergers is that they seem to pressure up a little faster than the Hornady SSTs, and they are longer, so less usable case capacity.

        It makes sense to tap out at 31.2gr with them, whereas Hornady's data shows 31.7gr for the 129gr bullets with their jacket construction.

        CFE223 is definitely the powder to beat for speed with 120-130gr cup and core bullets.

        Nice to see you using .3gr charge weight increments.

        Precision Firearms and Federal both have 130gr Berger loads, Federal's new one being in their Federal Gold Medal Match product line.

        Very few cartridges have Federal Gold Medal Match ammunition.

        Do you have the Grendel Handbooks we published? They are the most comprehensive source for Grendel load data, as well as component selection, procedures, barrel length considerations, hunting, target loads, cartridge history, chamber variations, etc.

        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

        • VASCAR2
          Chieftain
          • Mar 2011
          • 6219

          #5
          Very good report, you’ve probably read CFE223 is not real stable when it comes to temperature change. Doing your load development in 45 degree weather will likely increase velocity and pressure on a 90 degree day. Not a big deal if your developing a hunting load for winter. Might be a consideration if you plan on shooting long range year round.

          Comment

          • heyyouguesswho
            Unwashed
            • Nov 2017
            • 19

            #6
            LLRP - Thank you for ringing in; I’ve enjoyed many of your posts and sharing experiences. I have been reading about the PF and GMM ammo but haven’t crossed paths with any of it as of lately. A tremendous thanks for the referral to the Loading handbook. I’ll be digging into that later today - cross reference and experience data are greatly needed.

            VASCAR2 - I’ve read that but went with the CFE for this initial load as it didn’t appear 8208 would put up adequate velocity numbers. I’ve also seen a few different charts tracking the variations per degree. I’m in Iowa and it’s quickly cooling off for the year. Last weekend was 45, today is 10 and falling. Yay. I’ll likely start fresh next Spring and approach a workup rather than assuming dropping a few tenths is safe. But I am open to suggestions if there’s more efficient data.

            As stated the purpose of this build and the ammo development is to get a semi-auto that can consistently ring the 1000 yard gong. I have a 308 and also a Creedmoor that can. My ultimate intent is to have a hunting/game load and a target load. Based on experiments and fellow shooters’ experience with Berger Juggernauts in 308, this was my starting point. I’ll probably shoot the bucks on some ABLR’s for the hunting load - but some of the stuff in Lead-Free thread has my attention.

            YOU GUYS ARE A GREAT RESOURCE! THANKS TO ALL at 65GRENDEL.COM!!!

            Comment

            • heyyouguesswho
              Unwashed
              • Nov 2017
              • 19

              #7
              Update #1

              Last weekend I had the opportunity to run my ladder test. First 'calm' day we've had in weeks. Since I started a bit lower than my test batch and worked up to the top of the food chain, I found a secondary 'node'. In my first batch, we started at 29.7gr and worked up 0.3 grain increments to 31.2 grain. For the ladder test at 300 yards, I started at 29.6 and used 0.2 grain steps to 31.4 grain. 31.2 and 31.4 grains of CFE are starting to show pressure signs - that is my limit. Test ambient temperature was 50 degrees and when it warms up late spring I'll back it down and try this again.

              At 29.4, 29.6 and 29.8 all had damn near the same point of impact. 30.8, 31.0 and 31.2 all had damn near the same point of impact. There was some small left-right variations with the light breeze but vertical stringing was all but non existant. 31.4 ended up being a flyer. All holes were very clean, no keyholing or apparent instability. This confirms my node that we documented at 30.9 and very little shift at 31.2. This also laid out a similar node lower velocity surrounding 29.6.

              All rounds were loaded to the ogive of 1.655" which gave me an OAL (averaging for tip variations) of 2.263". My C-Products mag let me get away with up to 2.265". Primers are CCI BR-4.

              I've now made a small batch at 31.0 grain. Next calm day I get, we're going to push the distances out to 600, 880 and maybe 1000.

              -Aaron

              Comment

              • Cornbread
                Warrior
                • Dec 2015
                • 288

                #8
                If those es numbers are right that is going to be a devil at long range on your vertical. If you are using an optical chrono make sure the sensors are square to the bullet path. Also, cfe can be temp sensative so be careful with a load worked up now in warmer temps. Looking for normal pressure signs at the relatively low saami max of the grendel can be deceiving. The max presssure is due to the bolt head diameter and stress on the bolt lugs etc. I would look into the ASC mags as they are cheap and will let you load out to 2.295. I would check the distance to the lands. Also, once you settle on a powder charge a coal ladder may be beneficial.

                Comment

                • kmon
                  Chieftain
                  • Feb 2015
                  • 2095

                  #9
                  I have worked up loads for the berger 130 hybrid and CFE223 in a lot warmer conditions and with Lapua brass COAL 2.27 started getting sticky bolt lift on the bolt action at 30.9gr on a 100+ degree day. I didn't try that load in the AR since it was a little hot in my CZ with an Obermeyer 8.4 twist barrel. 30.6 is a good accuracy load in both the CZ and AR with 24inch overwatch upper .3 and .6 respectively. Same data shoots well from my guns with the 129gr LRAB, no quite as accurate as the bergers but I have not done much load development with them yet, tried 30.6gr with same setting on the seater stem and got less than .75 inch groups at 100 and 3 inch group at 300 so good enough for my hunting load at the ranges I normally shoot at, that is well within minute of deer or hog.

                  Welcome to the horde and keep it up, this is a fun little round.

                  Comment

                  • LRRPF52
                    Super Moderator
                    • Sep 2014
                    • 8569

                    #10
                    I don't recommend going over 30.4gr of CFE223 in the AR15 under a 130gr Hybrid.

                    That's where we saw 50kis under the 129gr ABLR, so you may be higher even with that charge.

                    31.0gr or more is more than likely well over 50ksi.
                    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

                    • heyyouguesswho
                      Unwashed
                      • Nov 2017
                      • 19

                      #11
                      Thanks for feedback and as LLRP had discussed earlier in this thread - we are probably pushing my luck.

                      I'm going examine that lower node I found centering at 29.6.

                      Comment

                      • heyyouguesswho
                        Unwashed
                        • Nov 2017
                        • 19

                        #12
                        Originally posted by Cornbread View Post
                        If those es numbers are right that is going to be a devil at long range on your vertical. If you are using an optical chrono make sure the sensors are square to the bullet path. Also, cfe can be temp sensative so be careful with a load worked up now in warmer temps. Looking for normal pressure signs at the relatively low saami max of the grendel can be deceiving. The max presssure is due to the bolt head diameter and stress on the bolt lugs etc. I would look into the ASC mags as they are cheap and will let you load out to 2.295. I would check the distance to the lands. Also, once you settle on a powder charge a coal ladder may be beneficial.
                        Thank you for the referral on ASC Mags - I'll shop a couple!

                        Comment

                        • SP1776
                          Unwashed
                          • Mar 2018
                          • 1

                          #13

                          Comment

                          • hikfromstik
                            Warrior
                            • Oct 2016
                            • 190

                            #14


                            Cfe223 isn't o the list but a few Grendel powders are .

                            Comment

                            • grayfox
                              Chieftain
                              • Jan 2017
                              • 4295

                              #15
                              Your loads sound to me like they are above safe levels for the Grendel. Since Gr brass/loads are a mild pressure load system (~50-52ksi) the brass, primer and such "normal" AR-type pressure indicators are not reliable fore-runners... if they occur you are probably already beyond max. This will shorten bolt and brass life. When '52 speaks up on pressures it is wise to heed.
                              Just sayin' - we don't want any face-type surprises to happen to you!
                              "Down the floor, out the door, Go Brandon Go!!!!!"

                              Comment

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