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6.5 grendel accuracy issue

Dildobaggins

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Minuteman
  • Jun 26, 2020
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    So... I have a 6.5G. Criterion 22"Hbar and CMC 2.5lbs trigger. Everything else is pretty AR standard. Shooting off a bipod and rabbit ear protektor rear bag off a bench.

    I'm trying to keep my loads as consistent as possible, powder charge, neck tension, seating depth etc. Using Hornady brass, H-335 powder and 120 grain ELD-M. First time I took it out, I had them loaded to the jamb point, groups were
    .247., 875., .454, 1.241 1.35 etc. Pretty much all over the place.

    took the gun home refusing to assume it was me. Found a really bad carbon ring with my bore scope. Cleaned it. Loaded some rounds .01 and .02 off the lands. Took a week off and just dry fired/worked on fundamentals, until I was confident. Went to the range today and I felt all the shots felt good and below are my groups.

    Questions: is this me and my fundamentals?

    is H335 better with bullets in the 80-100 grain range? Any suggestions on how I can make this load more accurate?

    anything anyone can tell me by looking at these groups, other than how horrible they are? The 3 groups that are more consistent are the ones loaded .01 off the lands.

    thanks fellas
    IMG_20221027_234122.jpg
    IMG_20221027_234053.jpg
     
    What charge weight and what velocity?

    Have you tried factory ammo using either the 123 ELD-M or Sierra 120 Match King?
     
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    27.2gr. I haven't tried any factory ammo other than federal 120gr OTM. It was sub MOA. It was last year. I'd say it was around .75. I just ordered a Chrono, should be here next week. I also noticed the brass is ejecting at like 5oclock.
     
    Gas system length?
    Buffer weight?
    Velocity?
    OAL to be at lands?
    Pretty sure 120 ELD-M at 0.040-0.060 is going to work really well. Zero reason to be at lands, 0.010 or 0.020” off lands, IMHO.

    I’ve never used H335 in 6.5G but have had positive results with 120 gr bullets and:
    H322 (lower velocity but great accuracy), IMR8208,
    H4895 (little on slow side but accuracy was there),
    AA2520
    Viht N-530 and N-540
     
    The Federal 120 is a Sierra and the "barrel tester" bullet for 6.5 Grendel. It shot that fine so isn't a bad barrel at least.
    As @FCS is pointing out a little slower velocity may be the answer, 26.6 gr should put you around 2443 fps but at a 1.2 ms barrel time.
     
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    Rifle length
    A2 buffer
    OAL to the lands is around 2.260 I dont actually know. I just know the jamb point is 1.6840 using CBTO. I'll try seating them further back. I just felt like they shot better at .01 off the lands rather than .02. but I'll back it off more and see what happens.
     
    The Federal 120 is a Sierra and the "barrel tester" bullet for 6.5 Grendel. It shot that fine so isn't a bad barrel at least.
    As @FCS is pointing out a little slower velocity may be the answer, 26.6 gr should put you around 2443 fps but at a 1.2 ms barrel time.
    That sounds good to me. I'll try backing off the charge weight. I don't know why, but I feel like when I'm reloading (which I'm still new to. Only a year in.) That I should try and archive max velocity without seeing pressure signs. Funny you say that. Some of the best groups of my life were in my .223 with 21.6gr of H-335 and the bolt wouldn't lock back or cycle got great groups with pretty much every powder charge though. That's with my WOA barrel.
     
    The problem with Grendel is by the time you see one of the classic pressure signs (smears, flat or cratered primers) you are already way way past a safe pressure.
     
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    The problem with Grendel is by the time you see one of the classic pressure signs (smears, flat or cratered primers) you are already way way past a safe pressure.
    Great info man. Thank you. I'll be hitting the range Monday or Tuesday. I'll try loads in the 26gr range and seating them a little deeper.
     
    So tomorrow I'll be going to the range. Lower powder charge and bullets seated further back. However, I think I've found a problem with my fundamentals. I've left out a rather large detail. I'm new to the range. Every time I've ever shot, it's always been prone in my back field and I'm able to load the bipod. When I was shooting off the bench, the bipod was infact jumping and I was not loading it. That might explain the small and large groups perhaps?
     
    Mine liked wc844 which is a lot like h335, with the 100g sierra bullets. Mine wasn't shooting well at first. I tried a flat wound spring then a wolf extra power spring with an H3 buffer. I went back to an H2, with a regular carbine spring, tuned the gas to that with an AGB, and it shot pretty good after that.
     
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    Mine liked wc844 which is a lot like h335, with the 100g sierra bullets.
    Ive got about 45, 120 eldM left. Then I'm going to try those or 95 grain vmax. Anyone you know that makes 100 grain ballistic tip or softpoints for the 6.5 calls? I'd like to try them for varmint maybe.
     
    Hornady does have a .264 100 gr ELD-M offering
    Really? I havent seen them. I'll have to search harder. That would be my ideal round. Took two deer up here last year with the 120eldm. I'd like to try the 100 and get a little more velocity
     
    So the crappier of the two groups was with my old load. The other one was with backing off the powder charge to 26.6. I suppose the groups were smaller, and about half are sub MOA, but I'm still not happy. I'll be ordering different bullets tonight, and give the H335 another shot. Perhaps my gun just doesn't like the projectile or powder? When I shoot my 223 with a WOA barrel 99 percent of the groups are sub MOA, and half are under under 1/2 sub moa. wish I knew what was going on here.
    IMG_20221103_134333~2.jpg
    IMG_20221103_134530.jpg
     
    2 comments:

    - Primers are a crappy estimate of pressure. They can be affected by headspace just as much, causing false pressure signs. And different primers will show different levels of flattening or cratering. Don't rely on how your primers look, that's amateur hour.

    - 3 shot groups are fine to show when a load doesn't shoot well, but if you start seeing tighter groups you need to put more rounds on target to know what it's doing. And don't just shoot 3 (or 5) shot groups at a bunch of different targets. Shoot them at the same target.
     
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    Try some WAY off the lands. I load mine mag length and and pretty pleased with the results.
     
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    2 comments:

    - Primers are a crappy estimate of pressure. They can be affected by headspace just as much, causing false pressure signs. And different primers will show different levels of flattening or cratering. Don't rely on how your primers look, that's amateur hour.

    - 3 shot groups are fine to show when a load doesn't shoot well, but if you start seeing tighter groups you need to put more rounds on target to know what it's doing. And don't just shoot 3 (or 5) shot groups at a bunch of different targets. Shoot them at the same target.
    When I think I've found a load I will do more shots on the same target. To be honest. I wasn't even going to shoot three. After seeing two, I knew the group couldn't get any smaller, but I wanted the data.
     
    Try some WAY off the lands. I load mine mag length and and pretty pleased with the results.
    I just ordered more bullets in 95 grain. And 120 eldm. I am going to go .06 off the lands like @FCS said. I loaded a dummy .06 off the lands and it was very short. Measured my jam point 10 times with a Hornady OAL guage. CBTO Longest was 1.8640 shortest was 1.8620.

    .06 off the lands is very short, but I can't see how it could possibly hurt.

    Should I stick with a certain powder charge and test seating depth and then play with powder charges?
     
    What powder(s) are available?

    95 Vmax and VV N-133 is a great combo. H322 is close second.

    120 ELD-M would do better with slower burn rate like IMR8208, VV N-530, AA2520
     
    What powder(s) are available?

    95 Vmax and VV N-133 is a great combo. H322 is close second.

    120 ELD-M would do better with slower burn rate like IMR8208, VV N-530, AA2520
    Trying to get these to fly with some H335.
     
    H335 is probably a better fit with 95 or 100 gr bullets, slightly fast in burn rate for 120 gr.

    Berger used to make a 100 Match BT, great bullet for the 6.5 G but was discontinued 10 years or so back.
    100 Nosler BT, 100 Amax/ELD-M, 100 Scenar are all pretty nice to work with but have become unobtanium last couple years.
     
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    H335 is probably a better fit with 95 or 100 gr bullets, slightly fast in burn rate for 120 gr.

    Berger used to make a 100 Match BT, great bullet for the 6.5 G but was discontinued 10 years or so back.
    100 Nosler BT, 100 Amax/ELD-M, 100 Scenar are all pretty nice to work with but have become unobtanium last couple years.
    I'd like to try any berger bullet. I will eventually with my 6 creed. I found some 100 and 108 grain Lapua scenars. Might try them after the 95 VMAX. Never really noticed but a lot of offerings from nosler seem quite steep on the price.
     
    Yep. The Nosler 100gr BT is probably my all-time favorite, but just too expensive to shoot if you can even find them.
    Agreed, Nosler has gone absolutely loony with their prices. Even buying their blems costs as much as a lot of other bullets of equal or better quality. I pretty much only use Nosler for specialty bullets any more, definitely not for loading/shooting in any volume.

    One example is the 129 ABLR - an excellent Grendel bullet, since it's expansion velocity window is well suited to even short barreled Grendels. I buy a hundred or two at a time when they have them as blems, and use them for load workup, verifying zero, and hunting, but they aren't practical to shoot a lot of them, and nothing else really matches the weight and trajectory well enough to use as a practice substitute.
     
    Agreed, Nosler has gone absolutely loony with their prices. Even buying their blems costs as much as a lot of other bullets of equal or better quality. I pretty much only use Nosler for specialty bullets any more, definitely not for loading/shooting in any volume.

    One example is the 129 ABLR - an excellent Grendel bullet, since it's expansion velocity window is well suited to even short barreled Grendels. I buy a hundred or two at a time when they have them as blems, and use them for load workup, verifying zero, and hunting, but they aren't practical to shoot a lot of them, and nothing else really matches the weight and trajectory well enough to use as a practice substitute.
    The 129 ABLR is my second favorite bullet for all the reason you mentioned. It cuts through the air pretty well for long distance. My son and I were shooting them at 642 yards a few weeks ago. 5.5 mils to get there. Taking them out to 1K+ in a few weeks to see how they do and to put a spanking on my son who shot slightly better than me on that day. Tired of hearing about it.
     
    I used to use 8208 XBR. Ill have to look through my loads that I used to shoot with it. I had a load with the 123gr BTHP from Hornady that was about .5-.75 MOA. I also used CCI 450s to light it off and they were just loaded to mag length.

    Doc
     
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    I used to use 8208 XBR. Ill have to look through my loads that I used to shoot with it. I had a load with the 123gr BTHP from Hornady that was about .5-.75 MOA. I also used CCI 450s to light it off and they were just loaded to mag length.

    Doc
    I loaded the 120 eldm to mag length and they jammed pretty bad. I'd be interested in your data!
     
    So why did you settle on the powder charge that you did? What did your other groups look like. From just scanning it looks like you just guessed on a powder charge and ran with.
     
    So why did you settle on the powder charge that you did? What did your other groups look like. From just scanning it looks like you just guessed on a powder charge and ran with.
    I looked in my Lyman handbook and it stated a starting charge for 123 at 26.3 and a max of 27.5 so I figured I wanted to be near the max because I was hunting an antlerless season last month and wanted the velocity because I knew I'd be making longer shots. Took a look at Hornady load data just now, and with H335 is only 24.6 and a max of 26.4 I need a Chrono for sure. But Monday I have 200 95vmax and 200, 120 grain eldm coming. Perhaps I'll start at 25 grains and work my way up with the 120 eldm?
     
    You need to find an optimal charge weight. I’ve read and reread all the 6.5 Grendel load data on this forum. I will tell you my Grendel’s are 1-1.5 grains lower with the OCW than the average on this forum.

    But I’m not chasing velocity. I don’t care how fast the bullet is going if I can’t hit my target.
     
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    You need to find an optimal charge weight. I’ve read and reread all the 6.5 Grendel load data on this forum. I will tell you my Grendel’s are 1-1.5 grains lower with the OCW than the average on this forum.
    Will do. I'll start at 25 and work my way up. I already know what happens when I hit 27.2 and up. Haha
     
    So why did you settle on the powder charge that you did? What did your other groups look like. From just scanning it looks like you just guessed on a powder charge and ran with.
    I suggested the 26.6 based on his available components and barrel length which predicted what should be a favorable barrel time according to the P-max simulator.
     
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    I suggested the 26.6 based on his available components and barrel length which predicted what should be a favorable barrel time according to the P-max simulator.
    One of the last pictures I posted had more consistency that was with a 26.6 charge. I only did 3 groups with it though because I ran out of bullets
     
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    Doesn't mean it can't work for you, but now you know you have to move the seating depth in, not out. The big thing hurting everyone is little variety of available powder.
     
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    A footnote on my experience with 129 ABLR’s. Want to, but have yet to actually shoot something with them, but in working up loads to use for that purpose , found BTO variance of .007 in same two boxes of 100. Two close lot numbers-same variance. They’re now segregated by BTO, but would surely expect a better job of QC when paying what are now $70+/100 for a premium hunting bullet, and these were not seconds where I’ve seen over .020 variance.
    All said, I’ll use them, as I still think it’s a near perfect hunting bullet for anything 6.5, but do expect more rigid QC from Nosler than what they’re delivering in this specific bullet.
     
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    771CD312-FA08-4287-8A02-C0B7B0C38B86.jpeg
    C1AC1307-7CC2-4CCB-B312-A93B0796927B.jpeg

    120 Scenar
    Slightly slower burn rate powder than H335
    5rds @ 100
    6.5 oz buffer
    18” LaRue upper w/TranQuilo attached
    Mk4 6.5-20, TMR, FFP in NF Unimount
    D615A251-7636-4632-8E81-E1DA9D377407.jpeg
     
    The 120 ELD-M is meant for a conventional throat, is why this bullet is in a Creedmoor factory cartridge offering and not Grendel.




    If your barrel had one of the non-SAAMI bastardized chambers it might work better there.

    Most of the “bastardized” chambers have even less freebore than SAAMI 6.5 Grendel.

    120 ELD-M will probably shoot just fine and dandy when jumping 0.040” or so.
    H335 isn’t going to be a full case even if bullet is slightly deeper.

    I’d probably heavy up buffer a bit or turn down gas if AGB is installed.
     
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    So 28.6gr of 8208XBR
    2.275 COAL
    ASC mags.
    Was running 2685 out of 20" Saturn barrel.

    Doc
     
    I've got rounds loaded up that are .040 and .050 off the lands and charges from 25.8- 27.2 with 120 eldm. I'll be going to the range Monday or Tuesday and report back. Either way, thank you everyone for the help. Much appreciated.
     
    So 28.6gr of 8208XBR
    2.275 COAL
    ASC mags.
    Was running 2685 out of 20" Saturn barrel.

    Doc
    That same load is just over 2400 out of my Ruger 16”
    This rifle has a long throat. I loaded some long today to try out Tuesday from my 6arc aics mag.
    Tested some at 29gr today and was at 2440. No pressure.
     
    So I went to the range this morning. Forgot one of my ammo boxes. I shot the 120 eldm seated .04 from the lands, and powder charges from 26-27.2
    The lower end of the charges definitely did better and it was more consistent. I shot 2 groups of 3 shots for each charge. I need to learn to relax. I'd get two holes touching and get excited and then rip the third shot and pull it. First group in the top left were fouling shots with ammo I didn't seat correctly.

    So in conclusion. A.) Thanks everyone
    B.) The gun is more accurate than me,
    C.) I need to work on fundemtnals and learn to relax.
     

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    I’d say one of the biggest fundamentals to learn here for load development is to stop shooting groups of three. There’s zero reason to split up six rounds into two groups, just shoot all six at the same target. It’ll give you a better understanding of what the load is doing, and fewer lucky groups to mislead you.
     
    I’d say one of the biggest fundamentals to learn here for load development is to stop shooting groups of three. There’s zero reason to split up six rounds into two groups, just shoot all six at the same target. It’ll give you a better understanding of what the load is doing, and fewer lucky groups to mislead you.
    I suppose I should. I just figured if I pulled a shot, I've only wasted 3 rounds instead of 5 or 6. With load development, how many would you suggest shooting per powder charge/seating depth? 5? 10? More? Thanks, brother!