6x47L Help

Discussion in '6PPC, 6-6.5x47, 6XC, 6 Rem, 243' started by Clucknmoan, Oct 10, 2017.

  1. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    Need some help here gents, running out of options. Can't seem to get this rig to shoot anything.

    Rifle is a 6x47L, 26" 8 twist M24 Spencer barrel, Curtis Custom Axiom action in an MPA chassis. Just under 17 pounds in all.

    Brass prep. Turning the necks on Lapua brass to about .013 while at the. 264 diameter, (same method and K&M equipment that I use with all other cartridges). First step the necks down to 6BR in a Forster CoAx press, then on to a Forster 6x47L full length die, finish by expanding up with a mandrel to .0025 neck tension, champher mouth, debur flash hole...done. Brass looks great, square, no bell ends. After initial firing, cases are sized with a Whidden bushing die (and expanded with a mandrel), shoulders bumped right at .002. Bullets are seated with a Whidden seater and checked for runout.

    Ran about 10 rounds down the barrel to break in, inspecting an cleaning as necessary. Pulled the copper after the first and 10th rounds, no copper showed after that. Cleans up easy. Shot these 10 in .03 grain increments @ .005 off to see if I could find a flat spot while I was breaking it in and one showed at 3020 (110 SMK's). I usually shoot these in more or less an OCW style, you can usually see the POI shift around the bull and get a real good idea of what's going on. Of course operator error can happen when unexplained things show on target. Noticed right away during this test that there were severe flyers. Every 2 or 3 shots it would spit one 1.25" off somewhere, then return halfway close to where it should be.

    First firing of cases all seemed to have a little heavy bolt lift and the start of a cratered primer. I assumed that pressure would be a little higher initially when forming these to the 6x47 chamber from 6.5x47 brass.

    Seating depth test first for 110 SMK's. Seated 3 each at .005, .025, .045 off with 39.3 grains of H4350, CCI 400 primers. No preference was shown for any seating depth, there was at least one flyer around 1.25" in each group. ES was shockingly good at 14, 6, and 6...small sample size I know. Velocity was 3045, 3026, and 3011 respectively, decreasing as expected as depth increased. What I didn't expect was a heavy bolt lift and ejector marks on everything seated .045 off. Higher velocities did not show any pressure really.

    Since none of the seating depths showed favor, I chose .005 off and loaded up 5 at the flat spot I found before to see what they would do. Velocity was as expected, but the group was about 1.75". I am not sure I have had any rifle ever shoot a group that bad when loading for it.

    At this point I started questioning my brass prep...didn't know what else it could be. So I took the 5 cases I just shot and loaded them again to see if perhaps that was the issue. This time it shot slightly better, maybe 1.25"

    At this point I started checking everything. Rings, rail, action screws, make sure barrel is floated and cleaned it. Nothing helped. I did multiple tests like this with 110's and nothing was any better. I have also started the process with the 105 hybrids and so far it's doing the exact same thing although I am not done yet. I am going to try a few more things with 105's and I am going to swap out the scope today. If that doesn't work, I'm stumped.

    Other things that don't add up. Brass is always tighter than expected coming out of the chamber after firing. Doesn't matter if it is once fired or virgin, just heavier bolt lift that one would expect or want even when there is no pressure signs. Primers are almost always somewhat cratered no matter the charge, even if no other pressure sign is apparent. The neck on shot cases are about .001 out of round as you rotate it in the calipers.

    There is an accuracy guarantee of 3/8th for the rifle, but I want to make sure I cover all my bases before going that route. It seems to me that if a rifle is going to shoot well, it normally shoots everything reasonably well. This doesn't shoot anything worth a crap so far. Normally you would see some sort of direction on paper of where to go, but this is giving me nothing and I don't want to continue blowing $$ and time out the muzzle for no results.

    What am I missing here? Any help would be appreciated.
     
  2. JBT

    JBT Gold $$ Contributor

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    Have you tried any bullets other than 110's? I'm driving so did not read your post in its entirety.

    8" twist probably not fast enough for the 110's.
     
  3. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    Yes sir. Tried the 105's as well but not to the extent that I did with the 110's. For what it's worth my buddy has the same rifle with a different action, his shoots the 110's. I also made it clear I wanted to shoot the 110's when ordering.
     
  4. MDM

    MDM Silver $$ Contributor

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    Try putting the 110 .010 into the lands. I found the 110 a solid .5moa at .010 off or more, but it really came to life when I put it in the lands. Using Berger's stability calculator, you are at 1.27 for stability and are compromising the BC by 7% with the 8 twist and 110. Berger even recommends a 7 for the 105s, but not many run them with it. You should have a node somewhere close to 3050-60 with the 105 .015 off. It will take 150 rounds for the barrel to completely settle in and get your velocity stabilized. I run 39.6 in a 7 twist with 110s. I know guys that shoot them in an 8 twist and some can't get them to work in an 8.
     
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  5. MDM

    MDM Silver $$ Contributor

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    Also, run 450s in it if you can. 400s have softer cups.
     
  6. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    Will do. I'm at 3200 feet so the stability is a little better, but still not in the comfortable zone.

    Also I realize it will be a few hundred shots before everything stabilizes but I hate to put 200 rounds down a barrel that isn't going to shoot. Thus far I haven't had an ES over 19, but I know I will have to compensate in charge as the barrel speeds up.

    Very much appreciated.
     
  7. MDM

    MDM Silver $$ Contributor

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    I'd focus on the 105s while you are trying to get any problems sorted out. You might be chasing your tail a little with the 110 if its marginal stability and that bullet can be a little finicky in my experience. If you can't get the 105 to shoot with a little jump, I'd be inclined to think you may have an issue somewhere. That said, mine will shoot the 105/108eld/110/105vld all really well with the same charge, I just have to put the 105vld and 110 in the lands a little.
     
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  8. JBT

    JBT Gold $$ Contributor

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    At your elevation the 105 Hybrid should be ok. I really do not believe that the 110's will be satisfactory out of 1-8" twist.
     
  9. dminn1

    dminn1

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    Since you are reforming cases you might compare your loaded round neck diameter to your chamber neck diameter and see if you have a clearance issue. I ran into this when reforming .243 cases from .308 and had to turn my necks a bit more. When I got to .003 total clearance things started to run fine. Just an idea.
     
  10. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    Yup, did that. Chamber looks to have a .275 neck and my loaded round is .271. I also trimmed before the first firing at one point in this process thinking I may be a little long. Did not seem to help.
     
  11. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    So this afternoon I did a little more testing. Replaced the scope with a proven piece of glass and proven rings. So that's out of the equation.

    Switched to 450's and 105's seated .015 off and did a quick velocity test and sure enough, a flat spot about .6 grains wide right at 3050. Loaded 6 in the center of that flat spot and they shot an average of 3050, ES of 12. Group size was still right at 1".
     

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  12. SG4247

    SG4247 Silver $$ Contributor

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    Interesting, albeit frustrating issue. My experience with 105s in the 6x47 as follows:

    On my 6x47 28" 7.5 twist, BAT B, I tested the 105 Berger BTT .010" off using H4350. I started at 34.5 gr and went up to 39.0 gr in .3 gr increments. Used 2.630" OAL. Had .240" neck ID with .012" wall thickness - after sizing down to 6mm.

    5 shot Nodes that were .3" or better @100 yards were at:

    35.4 .300"
    36.2 .100"
    36.3 .250"
    38.1 .300"
    39.0 .250"

    Worst groups were at .725" at 38.8 and 38.9 gr. then it shaped up at 39.0 and gave me 5@.250" were I stopped.

    39.0 was max in my rifle. Started to get heavy bolt lift, worried about galling the lugs, so I stopped.

    I then switched to the Berger 105 VLDT and repeated the same test on a different day, with H4350. With this bullet, OAL was at 2.710" OR .008" off the lands

    At 300 yards in the wind:

    First Target 5 shots @ 36.3 grains are .720" or .23 MOA

    Second Target 5 shots @ 36.3 grains 5 @ .800" or .25 MOA

    Same node as with the 105 BTT!

    These checked at 2838 ft/sec ave with SD 10.

    If your rifle wont find a node in this range, with any 105 Berger and H4350, then I would bore scope it from chamber to muzzle. Something must be off center somewhere.

    Not sure if my gun would really shoot well above 39.0 grains of H4350, with 105 weight bullets.

    Just my experience..
     
    Last edited: Oct 10, 2017
  13. 6.5creed

    6.5creed Silver $$ Contributor

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    Lots of good advice here so far. Only thing I would add is when testing seating depth I go in .003 increments and usually find a seating node between .006 & .012 wide, easily missed in .020 seating increments.

    Good advice on the 450s for primers. If they're still cratering you may need to Bush your bolt. I had to do my Remington to keep from blanking primers where it wanted to shoot.
     
  14. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    I can see adjusting by .003 to refine an depth adjustment, but I always start with a course adjustment to get in the ballpark. I don't usually do the .040 spacing that Berger recommends for course testing, but this is the first time I can recall one depth .020 apart not outperforming another. Or at leaat one significantly worse than the others. I stopped this time @ .045 off because of pressure issues.

    This is now spitting random flyers and no better than 1" groups with 2 different bullets. I just don't see changing seating depth .10 or .15 tightening groups up an inch to acceptable levels.

    The primer cratering is fairly irritating also. I've had factory bolts crater primers and fully accepted it as a risk with a factory action. Sent it in to have it bushed or change out the bolt head, no big deal. But to have this happen on a custom action is a little different, I expect more.

    Tomorrow I will shoot these jammed .010 and see what happens. Any additional ideas would be appreciated, but if jamming them doesn't show some promise, this will probably be going back.
     
  15. boltfluter

    boltfluter Gold $$ Contributor

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    I have both a 6x47 and a 6.5x47 and neither will shoot well with H4350. But, both are tac drivers with Varget. Just a thought. Good luck.;)

    Paul
     
  16. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    Thought about this too, kind of dismissed it since it 4350 showed great stable flat spots and ES has been very good.

    Ever had a powder act exactly as it should but pattern like a .410?
     
  17. boltfluter

    boltfluter Gold $$ Contributor

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    Strangely enough I have. It was a .22BR that had great numbers with Varget but would not crack 1" no matter what I did. Tried my old standby powder of AA2015BR, and I'll be damned if the first load didn't shoot a .5" group. Sometimes a gun just doesn't follow the normal rules.:D:D

    Paul
     
  18. MDM

    MDM Silver $$ Contributor

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    Try Varget but about 3-3.5g less than your 4350 load, should put you in the same velocity node.
     
  19. Grimstod

    Grimstod Web Designer for PremierAccuracy.com Gold $$ Contributor

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    I would size first then neck turn. Necking up and down always introduces inconsistency in neck wall thickness. Especially if one sode of the neck is harder then the other.
     
  20. Clucknmoan

    Clucknmoan Silver $$ Contributor

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    This was the original plan and how I prepped some brass initially. When I started seeing flyers everywhere, that's when I started turning the necks at the 6.5 size before necking down. I assumed my issues had something to do with case prep. I was just trying to get some more consistency in my process and make sense of the terrible groups.

    I'd like to turn the necks after the first firing in the .243 state if I could get away with waiting that long.
     
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