Inconsistent Groups

Discussion in 'Reloading' started by 6.5Express, Jun 21, 2011.

  1. 6.5Express

    6.5Express Well-Known Member

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    I've lurked around here long enough combing these threads that are full of excellent information. My problem is this: I've been trying to work up loads in my 264 WM and cannot seem to get consistent results. I started with 140 gr vlds and couldn't get any powder to group well - everything was 1.5 - 2.0 moa. Tried 130 grain vlds and got the same results. Changed from CCI to WLRM primers and all three powders I was working with produced sub moa groups! Chose to work up with WIN 780 Supreme based on book velocity. Worked up to 67.0 grains with no pressure signs. 66.0 produced a .34" 3 shot 100 yd group. At this time, I ran out of new brass - I neck sized a few (with a neck-sizing die) and chambered to insure neck sized loads would function properly. Back out to the bench with the once fired neck sized loads - really sticky bolt and no group (1.5 - 2.0 moa). Went back through the lot of brass and full length sized all (these had all been full length sized, fired once, and neck sized) brass. Various powders (win 780 supreme, 7828ssc, H1000) all will shot terribly inconsistent .5" one time, 1.5" a half hour later. Also, now I'm getting pressure signs (sticky bolt, cratered primers) with 66.0 gr of 780 supreme (with full length sized brass)!

    Why am I getting pressure signs with a load that was already worked up in the same rifle - same lot of powder, primers, bullets, and twice fired brass? Did sizing the brass twice (neck sized, then full length) without firing in between mis-shape the brass? All brass measurements are consistent with book dimensions. Tonight I re-checked all action bolts, base / ring screws, etc.

    What say you?gun)
     
  2. Buffalobob

    Buffalobob Writers Guild

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    The temperature of the cartridge before it is fired is important. If it sit out in the sun or is allowed to sit in a already hot chamber it will affect the pressure.

    I would suggest you try RL22 and Fed 215 primers. If that will not give you good groups then consider that the problem may be somewhere else. Accuracy can be affected by parallax, bedding, barrel contact, poor bench skills, flinching, etc.

    If you can normally shoot half inch groups at 100 yards then you can pretty much rule out some problems but if not then you simply should realize that reloading technique does not compensate for poor shooting skills. This is much like the ability to shoot small groups does not compensate for not being able to find an animal to shoot at.

    Seating depth on VLDs is often a critical issue.
     

  3. BillR

    BillR Well-Known Member

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    Almost looks like your throwing too many variables into the works. When I start a new gun I will break in the barrel by finding a load a grain or so less than max and don't care what the accuracy is with it as I know this will change as I use new brass and the cheapest bullets I can find and besides breaking in the barrel with this load I am also fire forming my brass. Once the brass is all fire formed and the barrel broke in, (shoot clean, shoot clean etc. for 30 rounds and then shoot 5 clean, shoot 5 clean for another 20 rounds) I then end up with 50 cases that I neck size and trim to length and then begin my load work up. I also anneal those cases before sizing so I get consistent neck tension. I seldom use any powder besides one of the Hodgdon Extreme powders especially at this time of year. Outside temps can cause too many variables for me to deal with. When you bounce around from New case to neck size case to full length size case it introduces too many variables. Just pick one and work from there.
     
  4. Reloader222

    Reloader222 Well-Known Member

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    Seems that you have shot a lot of loads. Have you cleaned the bore with copper solvent? It could also be a buildup of copper fauling.
     
  5. 6.5Express

    6.5Express Well-Known Member

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    I broke in the barrel with 1 shot / clean for the first 10 rounds. Then 3-shot groups (beginning load development) - clean. Once I'd shot 30 rounds, I shot 5 shot groups (continuing load development) - clean. From about 50 til now (just over 200) I clean after ever 10 - 15 rounds (carbon and copper everytime). I've tried to concentrate on neck sized brass / win 780 supreme loads adjusting seating depth and powder amount and just don't have any consistency. A few times, I've gone back to some other powders that shot well with new brass (7828ssc & H1000). Both of these powders shot sub-moa with new brass and now will not group.

    The only other difference since I started is the weather has warmed 20 - 25 degrees. Maybe 780 supreme is temp sensitive?

    I don't think it's shooting form, bench practices, etc. Just to make sure, I shot 3 other rifles from the same set up. All were around .5 moa at 100 yards.

    I do run one oil patch down the bore (followed by a dry) after cleaning carbon and copper. I've heard some folks say it takes a dozen rounds to burn out oil - others swear by running an oil patch through???? Doesn't seem to make a difference in my other rifles.

    The rifle is a stainless cdl in 264 win mag. I put on a Bell and Carlson Medalist stock (with aluminum bedding block), and a VX3 6.5-20x50 LRT with talley one piece rings. Last night I checked all action screws and scope mount screws again.

    Maybe I just need to work up different loads now that the barrel is broke in instead of trying to force another 0.34 group with 780? I've got a bedding kit ordered. I guess the next order of business is bolt trueing?

    gun)
     
  6. cfvickers

    cfvickers Well-Known Member

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    I use a lot of 130 VLDs in my 6.5-284 and I use a carbon remover every 30-40 shots. I remove copper after about 100. This seems to work well for me. VLDs are sensitive to seating depth I am sure you have noticed. Go back over your reloading process and find your inconsistency. make sure you do exactly the same thing every time. Do you measure the OAL of every round? The first good thing I noticed you did was switch to winchester primers. some swear by CCI but the only consistent CCI primer I have found were magnums and that was in non magnum rounds. in summer back down to a standard primer. The powder is easier to ignite (to my understanding and experience) in higher temps of the summer. are the outside conditions the same from one day to the next when you are testing your loads? aside from temp check the barametric pressure at the nearest airport. Type in your zip code on weather.com and it will give you the pressure reading at the nearest airport with an ASOS system, then verify the difference in your altitude and that of the airport, from that look online to find how to calculate your pressure. if you are within 100 feet of altitude then there is no need to check it, it will get you close enough that it should not effect your shooting. bullets fly different when the pressure is different, and at some velocity/chamber pressure you will find a spot with the least deviation. Are you checking each shot on a Chronograph? These are a few subtle changes I have found to effect my groups that not everyone looks at. Again though, I would bet it is an inconsistency in your process somewhere. We all do it and have to check and recheck on a regular basis. Hope some of this helps. Some will say that I am sending you on a witch hunt with the pressures and what not, but I almost always find a discrepency when this is happening to me and I know my process is sound. Last thing, how much case stretching are you getting with each shot fired, and did you trim your cases. Failing to trim when needed is a sure fire group killer and can add pressure, the type of differences you are seeing. Been there and done that and the only way to find the issue is to go looking for it. a number of things can cause it.
    Last but not least is your shooting form and rest. I have a 22-250 Encore rifle that absolutely will not shoot the same with any load on any given day as the day before IF I rest the fore end in a vice type rest. However if I just rest it on sand bags I will consistently get the same results. What brand of brass are you using? if it is remington, I suggest throw it away and get winchester, nosler, or just about anything but remington. RP brass tends to be soft and I have found it to be at near max length even before firing the first shot. In my 300 win mag it tends to stretch and need trimming after the first shot is fired. In that rifle it absolutely will not chamber until it is trimmed. Hope you get where you need to be. I am sure I repeated someone at some point here but only in the interest of being thorough.

    Try some RL25 if 7828 isn't working for you. Accuracy trumps velocity in almost every instance. I am sure you know that, but it took me years to figure it out for myself.
     
    Last edited: Jun 23, 2011
  7. Mikecr

    Mikecr Well-Known Member

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    I don't understand all your abstracts in sizing.
    For load development, you should decide what size your brass will always be and put it there beforehand.

    New brass could be anything.
    NS'd only brass is different than new, or FL sized brass.
    Neck sizing before/after FL sizing is one sizing too many.
    You can't base pressure on case extraction until you know/standardize what sizes your cases are before firing.
     
  8. cfvickers

    cfvickers Well-Known Member

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    Neck sized brass can be a little sticky on the second shot.
     
  9. Casing

    Casing Well-Known Member

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    Personally I DO NOT put a round down the barrel with any oil in the barrel. If I have put any oil through the bore I will wipe it out with a patch with alchohol then dry the bore good with dry patches. I'm sure you've shot a rifle close to dark and have seen the flame from the powder burn? I don't like the thought of the oil in the barrel having to burn out. The barrel becomes an inferno and if you have something in the bore to "burn" such as oil it will likely glaze in the bore over time and can pre-maturely wear out the barrel. Also with a dry bore you always have one varible that remains the same, ie. a little oil, too much oil, or dry. Just my 2 cents.
     
  10. 6.5Express

    6.5Express Well-Known Member

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    Well, I found an inconsistency...This weekend, I went through and measured all the brass (Nosler). This is now been fired three times. Max case length is 2.500" and this brass is anywhere from 2.472 - 2.496! I sure didn't think I'd find something like that from a company like Nosler. I've never paid much attention to case length other than max and trim to lengths (max minus .010).

    Could this be a source of my issues, and can it be remedied, or do I need to throw out the brass and start over?

    Never came across brass almost .020" short of trim to.
     
  11. Mikecr

    Mikecr Well-Known Member

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    Nothing wrong, you just need to make ALL your brass the same, before load development.
    Prep pockets, turn necks, etc , then fireform.
    FIREFORMING is the only way to get it to baseline capacity.
    Then make em all the same length, and size them all the same way.

    With this, you can compare apples to apples during load development.
    Otherwise, well,, you're all over otherwise...
     
  12. cfvickers

    cfvickers Well-Known Member

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    Hornady .300 win mag brass has, in my experience, almost always measured around .025 short of trim too length. I have gotten my most accurate loads with this brass consistently. The only Nosler brass I have dealt with was around .020 shorter than trim too. I believe this is normal. It is likely done so that it will not have to be trimmed until fired 3-4 times. The variance is most likely from the fact you have already fired the rounds and in load developement you have induced varying degrees of pressure. With more pressure the cases will stretch more.
     
  13. diriel

    diriel Well-Known Member

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    Another thing to consider is after fireforming, only bump your shoulder about .001" so you will effectively headspace on the shoulder rather than the belt.

    Have a good one,
    Gary
     
  14. 6.5Express

    6.5Express Well-Known Member

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    What is the preferred method to adjust the sizing die to bump the shoulder .001? I loaded up some 130 accubonds the other night and was able to give them a whirl today - I was finally able to get consistency with 130 ab's and retumbo down around 0.75" at 100 yards. I think I will stick with the ab's for now as I have a mule deer hunt in october coming up and an antelope hunt in september. This should be a great load for both (even though I'd love try the 120 bt for antelope).

    Maybe I will come back to the 130 vld after hunting season. I was able to get real consistent velocity readings with 4831 sc, but I ran out of bullets before I could go through the vld seating depth test (accuracy was still +/- 1.5").

    Thanks for all of your replies and help!
    gun)