Load development, velocities a little disappointing so far

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  • Tearlach61
    Unwashed
    • Nov 2014
    • 20

    Load development, velocities a little disappointing so far

    I recently bought an upper assembly in 6.5 Grendel from JP Enterprises. I am really happy with the accuracy I am seeing so far (11 3 shot groups, 9 of which under an inch, in the aggregate the 11 groups of different charge weights with 2 different powders would all fit within 2") but I am a little disappointed with the velocities I am seeing so far. I have done two OCW strings with 123gr AMaxes: one with BL(C)-2 (I have quite a bit of that, in excess of 8 lbs) and another with CFE 223 (I have less than a pound now and no idea when I can get more).

    With my BL(C)-2 string my highest velocity 2393 fps with 30.5 (that was the highest reading, my lowest was 2326 fps with the same charge weight). I got more consistent velocities with 30.2 grains clustered around 2370 fps. My Hornady says I should be seeing velocities of between 2400 and 2450 fps out of an 18" barrel. I expected something more out of a 22" barrel. My overall cartridge length was 2.25". The Hornady manuel had COAL 2.245".

    One more thing. At 30.5.gr of BL(C)-2 I had one case that showed signed of pressure: there was like a black marker on the case head and what looks like a small gas cut on the primer. I saw the same thing with 31.5 gr of CFE 223.

    I see that there is an Alexander Arms pdf circulating that has powder charges starting at a full grain higher and COAL's at about 2.265" and velocities up in the 2570 fps range. So does lengthening the COAL give you more leeway as far as powder charges go?

    I plan on going to the range later on today. I have 10 rounds with 30.2 BL(C)2 at 2.25" and 10 more at 2.27" the plan being to clock them and do a 10 shot group each.
  • VASCAR2
    Chieftain
    • Mar 2011
    • 6219

    #2
    I am at 350 FT above sea level and at approximately 85 degrees 31.0 grains of CFE223, 123 grain Nosler CC produced around 2450 FPS out of my 20" Shillen barrel. An 20" barrel will probably loose 40-50 FPS compared to a 22" barrel. If your chronographing on a cool day close to sea level I wouldn't be surprised by those velocities if using 123 grain bullets. I don't know if your barrel is producing a little lower velocity or not but I would be curious what velocities your 22" barrel would produce with factory Hornady 123 grain A-Max or SST. My 16" J&T chrome moley barrel produces about 2425-2440 FPS on a 80+ degree day at 350' ASL with factory 123 grain A-Max.

    I noticed your using a 22" barrel but atmospheric conditions can really affect velocity. Optical chronograph's are subject to lighting changes along with distance from the barrel to the first sky screen. I know the angle of the sun affects the shadow cast by the bullet as well as any deviation from the true center path across the two sky screens. I have seen these variables affect the readings causing the reading to be displayed lower than a true velocity. Several avid shooters have compared the velocities using optical chronograph's compared to the magneto speed chronographs. It reminds me of comparing the different weights measured on trucks whether fixed or portable scales. There are just variables that come into play when even weighing a truck on a fixed scale and getting the same weight twice.

    One nice thing about the 6.5 Grendel is you don't have to have really high velocity to shoot long range. I have shot my 16" Grendel to 800 yards and my 20" out to 1000 yards.
    Last edited by VASCAR2; 11-15-2014, 09:40 PM.

    Comment

    • PredatorDown
      Warrior
      • Jun 2014
      • 239

      #3
      My go-to load with my 22" JP Enterprises barrel is 30gr of BLC2 pushing the 123 AMAX at a velocity of 2490. I'm also at ~3500ft ASL, but I never thought of altitude effecting muzzle velocity, just bullet drop due to decreased wind resistance.

      Comment

      • LRRPF52
        Super Moderator
        • Sep 2014
        • 8569

        #4
        Can you tell us more about your primer, brass, and maximum COL allowable in your chamber?

        Your speeds are about where you should be actually with BL-(C)2. I'm more concerned about the pressure signs you are having.

        Need to know what primers you are using. Also, measure your bolt length from tail to lugs for us.

        If you want speed, CFE is the go-to powder for 123gr, with pretty good stability as well. I easily get 2535fps with not even the max load of CFE from a 16" barrel, but I use 2.275" COL. Factory Hornady A-MAX and factory PF 123gr Scenar both average 2450fps for me from 16", so I have some things to compare to.

        I have never seen a pierced primer in my Grendel's.
        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

        • Tearlach61
          Unwashed
          • Nov 2014
          • 20

          #5
          Hornady brass, Amax 123gr. 30.2 gr of BLC2 TulAmmo KVB-223 small rifle primers.

          I have attached a pic of one of my cases from an earlier shooting session. That one is 30.5 gr of BLC2 and a COAL of 2.25" But I am not sure it is a pressure thing per se. I looked through my cases and it pops up now and again at lesser powder charges and without other signs of pressure. It's like there is a path for the gases to take and the gases take it leaving a bit of gas cut on the primer which I can feel with the tip of my finger nail.

          Today's shooting session went as follows: 30.2 gr of BLC2 COAL of 2.25" initially (10 rounds) but then I went to 2.27" for the last 9 shots. Of the 10 2.25" length rounds, 4 had black smudges on the case has but no really gas cutting. None of the 9 2.27" cases showed any smudging.

          The velocities seemed to tighten up as did the group with the longer COAL. I did 10/9 shot groups and for a stretch with 2.27" rounds, I was laying one round on top of the other though the group did open up before I was done.

          I am at 200 ft elevation. Today it was in the mid to high 20s. The 2.25" length rounds gave me velocities that were all over the map ranging from 2364 down to 2182. I almost wonder if the conditions were messing with me. I was losing the sun behind a hill. Of my 9 rounds of 2.27" length rounds velocities ranged from 2368 to 2437 with an average of 2380. I actually only got readings on 6 shots because of the changing light conditions.

          I am thinking of loading a bit longer, maybe 2.28 and see what that gives.
          Attached Files

          Comment

          • LR1955
            Super Moderator
            • Mar 2011
            • 3355

            #6
            Originally posted by Tearlach61 View Post
            Hornady brass, Amax 123gr. 30.2 gr of BLC2 TulAmmo KVB-223 small rifle primers.

            I have attached a pic of one of my cases from an earlier shooting session. That one is 30.5 gr of BLC2 and a COAL of 2.25" But I am not sure it is a pressure thing per se. I looked through my cases and it pops up now and again at lesser powder charges and without other signs of pressure. It's like there is a path for the gases to take and the gases take it leaving a bit of gas cut on the primer which I can feel with the tip of my finger nail.

            Today's shooting session went as follows: 30.2 gr of BLC2 COAL of 2.25" initially (10 rounds) but then I went to 2.27" for the last 9 shots. Of the 10 2.25" length rounds, 4 had black smudges on the case has but no really gas cutting. None of the 9 2.27" cases showed any smudging.

            The velocities seemed to tighten up as did the group with the longer COAL. I did 10/9 shot groups and for a stretch with 2.27" rounds, I was laying one round on top of the other though the group did open up before I was done.

            I am at 200 ft elevation. Today it was in the mid to high 20s. The 2.25" length rounds gave me velocities that were all over the map ranging from 2364 down to 2182. I almost wonder if the conditions were messing with me. I was losing the sun behind a hill. Of my 9 rounds of 2.27" length rounds velocities ranged from 2368 to 2437 with an average of 2380. I actually only got readings on 6 shots because of the changing light conditions.

            I am thinking of loading a bit longer, maybe 2.28 and see what that gives.

            TL:

            You need a different primer. Best all around small rifle primer going is CCI-450 magnum. Get some of them and you won't see this again.

            LR1955

            Comment

            • pds
              Warrior
              • Dec 2012
              • 128

              #7
              Originally posted by Tearlach61 View Post
              Hornady brass, Amax 123gr. 30.2 gr of BLC2 TulAmmo KVB-223 small rifle primers.

              I have attached a pic of one of my cases from an earlier shooting session. That one is 30.5 gr of BLC2 and a COAL of 2.25" But I am not sure it is a pressure thing per se. I looked through my cases and it pops up now and again at lesser powder charges and without other signs of pressure. It's like there is a path for the gases to take and the gases take it leaving a bit of gas cut on the primer which I can feel with the tip of my finger nail.

              Today's shooting session went as follows: 30.2 gr of BLC2 COAL of 2.25" initially (10 rounds) but then I went to 2.27" for the last 9 shots. Of the 10 2.25" length rounds, 4 had black smudges on the case has but no really gas cutting. None of the 9 2.27" cases showed any smudging.

              The velocities seemed to tighten up as did the group with the longer COAL. I did 10/9 shot groups and for a stretch with 2.27" rounds, I was laying one round on top of the other though the group did open up before I was done.

              I am at 200 ft elevation. Today it was in the mid to high 20s. The 2.25" length rounds gave me velocities that were all over the map ranging from 2364 down to 2182. I almost wonder if the conditions were messing with me. I was losing the sun behind a hill. Of my 9 rounds of 2.27" length rounds velocities ranged from 2368 to 2437 with an average of 2380. I actually only got readings on 6 shots because of the changing light conditions.

              I am thinking of loading a bit longer, maybe 2.28 and see what that gives.
              TL,
              That's a primer cup issue not due too over pressure but due to a weakness in the cup at the 'U' bend. I would not use them any more as that pin hole will cause pitting in you bolt face. 31.6 gr of CFE gave me an average of 2599fps with 123gr Nosler CC using Wolf SRM primers, AA cases at 70 deg temp here in Salt Lake City with a 22" PF Bartlein upper. COAL of 2.210" which puts the CC bullet 0.015" from touching. I consider that a max load for this chamber at that temp. I have no data on the AMAX bullet. It's bearing surface in likely different than the Nosler thus a different seating depth and operating pressures with this load.

              pds

              Comment

              • Tearlach61
                Unwashed
                • Nov 2014
                • 20

                #8
                You guys are starting to tell me something I don't want to hear. I bought a case of those things when there was not a primer to be had in this town. I had them shipped. I have burned through about a 1000 of them so far mostly with my 5.56. I do have about 5 boxes of Federal 205 small rifle primers that I can give a try and I'll see what's available at the stores here.

                I did a bit of an inventory. I have shot 89 rounds so far through my Grendel barrel (see notes attached). 10 of those showed some signs of gas getting past the primer. It does seem somewhat charge related. For example of 33 rounds fired w 29.3 gr of BLC2, only one showed smudging (I was using mild loads for my barrel breakin). Of 13 fired with 30.2 gr of BLC2 (OAL 2.25) 4 showed signs of smudging and gas cutting. When I lengthened my OAL to 2.27", 9 rounds with that same charge looked fine, no smudging or gas cutting.

                I have fired a total of 20 rounds with cfe223: 28.7x1, 29.3x1, 30.0x3, 30.3x3, 30.6x3, 30.9x3, 31.2x3, and 31.5x3 all with an oal of 2.25". Of those 1 each of the 30.9 and 31.5 load showed signs of smudging.

                So it does seem somewhat charge or pressure related.

                I took a pic of bolt face. See attached. After 89 rounds, there is a circle showing the edge of the primer. That circle does have some pits. For comparison, I looked at the bolt face of my 5.56 and it looks about the same but it's fired several thousand rounds so far. I have an -06 with about 1000+ rounds through it and it has that circle. I have a 44 that has that circle but no pits.

                So my plan at this point is to lengthen my OAL, I think I'll go to 2.28 or 2.29 with that same primer and keep an eye on it. I think I might run a batch of say 20 or 30 rounds with CFE223 but also with a longer oal see what that gives. I'll also try a different primer, my Federal 205 anyway, CCIs if I can get my hands on any.
                Attached Files
                Last edited by Tearlach61; 11-17-2014, 12:19 AM.

                Comment

                • pds
                  Warrior
                  • Dec 2012
                  • 128

                  #9
                  TL,
                  The gray colored ring around the firing pin hole is normal. There are several black/dark spots within that gray ring that appear to be pitting in the bolt face from the primer cup failure you show in your first picture. If those primers were USA (Rem, CCI Fed, etc) they would likely replace them but TulAmmo is Russian I think. I would bite the bullet and stop using them and get some CCI 450 or Rem 7 1/2. Fed 205 or 205m can be used but have thinner cups and you may get a slam fire when used in an AR type rifle.

                  pds

                  Comment

                  • Tearlach61
                    Unwashed
                    • Nov 2014
                    • 20

                    #10
                    Thanks! At a stroke my once infinite stash of primers has become rather finite. I'll have to identify a primer that will work and look to accumulate.

                    I will say though, I haven't noticed anything similar with my 5.56. I'll have to go through about 40 spent cases and I found one with marginal signs of gas leakage. I'll have to see if I can dig up more spent 5.56 cases.

                    Comment

                    • LR1955
                      Super Moderator
                      • Mar 2011
                      • 3355

                      #11
                      Originally posted by Tearlach61 View Post
                      Thanks! At a stroke my once infinite stash of primers has become rather finite. I'll have to identify a primer that will work and look to accumulate.

                      I will say though, I haven't noticed anything similar with my 5.56. I'll have to go through about 40 spent cases and I found one with marginal signs of gas leakage. I'll have to see if I can dig up more spent 5.56 cases.
                      TL:

                      Don't let it surprise you. Not all primers are made the same and the ones you have (I have them too) do not work well in the Grendel for reasons I don't know. Mine would hang fire in the Grendel but had no problems with any 5.56 loads. I just stick with CCI 450 or even Wolf Small Rifle Magnum primers. Given a choice, it would be the CCI 450 primers.

                      LR55

                      Comment

                      • Tearlach61
                        Unwashed
                        • Nov 2014
                        • 20

                        #12
                        So I managed to get my hands on some CCI primers, 400s though. I hesitate to go with magnums since the loads given in the Hornady manual were with standard primers.

                        I am wondering if the cause isn't something else though. I seat my primers pretty aggressively using a Hornady hand priming tool. Sometimes I put a bit of a crease into the bottom of the primer (see attached pic of a primed 45 case). I am wondering of that could be a contributing factor.

                        So I have primed 20 cases each w the CCIs and the Tulammo kvb-223s, being careful to prime slowly and stop as soon as I feel the seating resistance increase. Circumstances permitting, I'll fire them this weekend and we'll see what gives.
                        Attached Files

                        Comment

                        • bwaites
                          Moderator
                          • Mar 2011
                          • 4445

                          #13
                          Originally posted by Tearlach61 View Post
                          So I managed to get my hands on some CCI primers, 400s though. I hesitate to go with magnums since the loads given in the Hornady manual were with standard primers.

                          I am wondering if the cause isn't something else though. I seat my primers pretty aggressively using a Hornady hand priming tool. Sometimes I put a bit of a crease into the bottom of the primer (see attached pic of a primed 45 case). I am wondering of that could be a contributing factor.

                          So I have primed 20 cases each w the CCIs and the Tulammo kvb-223s, being careful to prime slowly and stop as soon as I feel the seating resistance increase. Circumstances permitting, I'll fire them this weekend and we'll see what gives.
                          That's not a good look. You are crushing the cup. That means the anvil may be sitting skewed and not receiving a proper strike.

                          Comment

                          • LRRPF52
                            Super Moderator
                            • Sep 2014
                            • 8569

                            #14
                            Originally posted by Tearlach61 View Post
                            So I managed to get my hands on some CCI primers, 400s though. I hesitate to go with magnums since the loads given in the Hornady manual were with standard primers.

                            I am wondering if the cause isn't something else though. I seat my primers pretty aggressively using a Hornady hand priming tool. Sometimes I put a bit of a crease into the bottom of the primer (see attached pic of a primed 45 case). I am wondering of that could be a contributing factor.

                            So I have primed 20 cases each w the CCIs and the Tulammo kvb-223s, being careful to prime slowly and stop as soon as I feel the seating resistance increase. Circumstances permitting, I'll fire them this weekend and we'll see what gives.
                            CCI450's are the main primers AA used then developing the 6.5 Grendel. CCI400's are thinner in the cup area, making them not recommended for AR15 use by most experienced reloaders. You can get away with it, especially in the cold, but I can't recommend them. You really should get the 6.5 Grendel Reloading Handbooks that we collaborated on as a forum. Recommended primers are on page 67. Here's a diagram that compares rifle primers:

                            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

                            • rg1
                              Unwashed
                              • Sep 2014
                              • 10

                              #15
                              My one test of BL-C2 powder with Hornady 123 A-Max bullets, Hornady cases, RP 7 1/2 and CCI 41 primers. Worked up to 31.5 grains of BL-C2.
                              CCI 41 primer---31.5 BL-C2---2568 fps
                              RP 7 1/2 primer-31.5 BL-C2---2546 fps
                              Shot in J&T 24" heavy barrel. No pressure signs. Work up to this level.

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