New #2231 200gr SMK for F/TR

Discussion in 'Big Stuff--7mm, 30 Cal, .338+' started by Quickoz, Jan 18, 2018.

  1. mike mccormick

    mike mccormick Gold $$ Contributor

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    FWIW...I have found a good load with the 2231s in my rifle. Bartlien 9.5-9:1 gain twist. Saami chamber. Bullets seated .040" off . 45.8 gr Varget in Starline srp cases. Br4 primer. 30" barrel giving MV of 2681fps. Testing so far gives .250 moa ten shot group @300yds.
     
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  2. Ned Ludd

    Ned Ludd Gold $$ Contributor

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    Laurie - I would think that using consistency of ES/SD at the target as a measure of stability and by extension, precision, would depend almost wholly on the exact cause of any instability that might be observed with a given projectile. If instability was evidenced soon after exit from the bore (i.e. typical pitch/yaw), you can easily envision that it could create measurable differences in ES/SD values over a 1000 trajectory. However, if the instability was due to some other factor that didn't materialize as a significant factor until late(r) in the trajectory, there may not be sufficient travel distance remaining to create a noticeable difference.

    I point this out because over the years, I have observed numerous references to "abnormal" ballistic behavior from the 90 VLDs at longer distances (800+ yd). Having fired many thousands of rounds of 90 VLDs, I have never observed any phenomenon that would lead me to believe the 90s start behaving erratically at some distance past 600-800 yd. Further, it is beyond clear that they can perform extremely well out to 600 yd, as numerous F-TR shooters have found in MR matches over the years. Together, those two observations would suggest that there are unlikely to be any unusual and significant instability issues with 90s straight out of the bore. If there were, it is unlikely that it would show up only after 800 yd or so.

    Along that line of reasoning, I can imagine a couple reasons why you might observe greater ES/SD values with 90s at 1000 yd than with a high BC 30 cal bullet. The first would be that they generally start out with much greater ES/SD than good .308 Win loads. In my hands, achieving ES values of 10-15 fps with .308 loads is usually not too difficult. In contrast, I rarely observed ES values like that with 90 VLDs loads; more typically 18-25 fps (or even slightly more) ES values are the norm. I attribute this in part to the fact that the case volume of the .223 Rem is just over half that of the larger .308 Win case. Even small variance in charge weight, case volume, neck tension, etc., would be predicted to have a much larger effect on velocity.

    The second possible reason is merely speculation, nothing more. I point that out because, as I mentioned above, I have never observed "anomalous" behavior from the 90 VLDs from 800 to 1000 yd. Nonetheless, it is possible there could be some design factor inherent to the 90 VLD that renders it less stable, or perhaps, more "sensitive", to external factors, but only after it has traversed some minimal distance (i.e. 600-800 yd). Such a factor, if it exists, would be akin to the dynamic instability caused by the boattail design of the 168 Matchking, in that it has a negligible effect on precision at shorter distances, but shows up quite readily at distances past 600-700 yd, or so. As I mentioned, I have never personally observed such behavior from the 90 VLDs, but acknowledge it as a possible explanation for certain behaviors others have reported.

    The only other observation I have that might deserve mention at this point is with respect to the latest generation extremely long, short bearing surface, high BC 30 cal bullets such as are the topic of this thread. I have talked to a number of individuals that have had similar experiences to mine in terms of tuning loads with these bullets. The bottom line is that some aspect of their behavior seems very different than other bullet designs. Despite significant effort, I have been unable to find a consistent tune. I have fired plenty of groups where you might put two or three in a row into the same hole, all of a sudden, one shows up 3/4 of an inch out of the group, at a distance of ~100 yd. There is no apparent rhyme or reason for this: velocity data appear normal, the rifle has a sufficient twist rate (9.0) and shoots quite well with other bullets. Basically, I am at a loss to explain the inconsistent grouping, other than as some possible design factor inherent within the bullet itself. I don't know if you can call this a "stability" issue, per se, but they are apparently not all flying consistently straight out of the bore. As you can imagine given the inconsistencies, I would not attempt to shoot them in a match at this point. I mention this behavior only to compare/contrast it with observations regarding 90 VLDs at 1000 yd. My impression that the two behaviors are completely different in that I've never had a problem getting the 90s to print tiny bughole groups.
     
    Last edited: Jan 18, 2019
  3. Laurie

    Laurie

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    This is the issue I suspect. I increasingly hear rumours that some (many?) of the 'Berger Challenger' bullets in calibres other than 224 now behave the same way - great short/mid range performance, then something goes wrong at long ranges especially in FTR where bullet speeds drop closer to transonic speed at 1,000 than hot Open calibre bullets do. A friend had a great 2017 season (finished it as the GB league FTR champion in fact) bar one four or five match fixture out of seven where he changed from 200.20Xs to one of its newly introduced leading competitors. He dropped from top three aggregate / stage-winning status to half way down the FTR field; told me afterwards that the bullets / load were great at 800, but lost consistency at 1,000. Hearsay and a sample of one but I hear talk like this from others too. What I don't hear so far - would love to as we need a wider field of proven top-performing bullets - is of others putting up solid, regular consistent good performance over 20-round matches under a variety of conditions.

    Yes, I hear what you say about larger terminal ES values won't show such behaviours if they only occur over the last hundred or couple of hundred yards of flight, but any significant increase at all will be indicative of something going wrong especially if elevations on the target deteriorate. My main club is starting off with Shot Markers now for all F-Class matches, as its year one of full electronic target use. I'll certainly be recording terminal ES/SDs to try to build a database and see if I can detect any differences between results for those bullets and loads I know are good performers and 'try-outs'. It might or might not tell me something - I'll have to see. As I shoot F/O these days, my first interest is Sierra's new 7mm 183gn MK. Unfortunately while Bryan Litz's latest rifle bullet performance edition includes this model it doesn't have the 308 #2231, so I can't compare them. However as the 7mm 183 has a near 28-calibres radius nose and shortish bearing surface length it sound a lot like a scaled-down version of the thirty. (But not in weight - 183gn in 7mm' 30-cal equivalent would be heavier, somewhere between 210 and 230gn.) Results for the 183 seven in a 284 have been at up to 600 in very limited use have been promising but so far inconclusive given bad weather conditions, but I'll try them on Sunday in a match at 900 in what is so far is forecast to be a day with more settled conditions.
     
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  4. Laurie

    Laurie

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    Interesting! Although I've found some new designs 'finicky', I've not suffered this. However, our experience with these new designs in whatever calibre is very limited in the UK as they only started to arrive long after the first US deliveries. There is also some considerable reluctance to try them amongst serious match shooters as they, especially new Hornady ELD-Ms, are very expensive here and don't offer large savings over equivalent and proven Bergers - nor is their availability in the UK any better than that of Bergers. Equally poor in other words!
     
  5. 6BRinNZ

    6BRinNZ

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    Thanks for this info Laurie - it is very interesting and with the ETs there is a possibility of collecting data, especially if its collected in conjunction with a LAB radar. The shotmaker system might be ok but in general a lot of confidence would be needed in the ET chronograph and the ET would need to be setup well. A point that has been made to me is that the temp sensor probe on some systems sit out in direct sunlight which in turn affects the readings.
    In the case of your friend do you know if he moved to a faster than 10 twist i.e. was the barrel/chamber optimised for that bullet? Even in a .308 200 grn at 800 yards it would be well above transonic I would have thought.
    I do think some of the new .308 200s have design flaws that are causing some sort of precision problem on target having been unable to get some working myself as Ned describes at short range i.e. 120 yards. So there appears to be two precision characteristics out there...1. it won't work at SR and 2./ some suggestion that past 800 there is a problem. My instinct suggests that those that don't work at SR are a design issue.
    I've read on other forums that there is a suggestion for some designs that > than 1.5sg and up around 1.7 might actually be needed in practice.
     
    Last edited: Jan 19, 2019
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  6. XTR

    XTR

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    I've shot some of the other 200 class bullets from a 1:8 twist and still got results as described above. Out of 20 shots 13 are great, 5 are outside of the ½ MOA vertical that is kind of the threshold for what we look for in F-TR, and 3 are WTF!, where did that come from.

    And, I have seen similar teasers at 100 yds testing seating depths. Three shot, in a lopsided hole, one close, and one clearly outside of the group.

    I've shot over 1000 rounds in testing, and several matches at 600 and 1000 on ETs where I could get good graphic feedback. I am not strong enough with the force to get them to work.
     
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  7. 6BRinNZ

    6BRinNZ

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    Interesting - thanks - actually I do recall now that you mentioned in another thread I think that you had used an 8tw for some testing.
    The pattern you described is pretty much it to a T!

    @Laurie - I ask about your friends setup not to doubt but its a good sanity check not to assume. :)
     
  8. Laurie

    Laurie

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    If they won't even group at 100, that really is dispiriting! I've tried some newer designs recently that I did get to work at 100 but only with a lot of effort and where they appear to be so finicky that small COAL and/or charge changes move them in and out of grouping well to grouping so-so or even very badly.

    For all the curses we Brits heap on our weather, it does at least usually stay pretty constant so we don't have to cope with large temperature changes in a day. (Or, even it seems at times between seasons. :) ) And .... I increasingly rely on Viht N100 series powders whose lot to lot consistency is very good indeed. BUT ... even so, I'm always very reluctant to rely on a load where some minor variation or other can push it into producing three quarter or even MOA verticals.

    Oh for the good old days where we all shot 7-calibre nose radius tangent-ogive old style Sierra MKs. No, as an inveterate experimenter I don't really mean that. In my 284 though, my fallback option is the elderly 175gn SMK whose BC is only 0.009 shy of that of the much pointier 180gn Berger VLD (0.018 for the Hybrid) and is delightfully unfussy about settings. In fact I've never changed anything over some 1,300 or 1,400 rounds down the barrel and four or five lots of Viht N165 - I just shoot a couple of 100 yard groups past the Labradar every now and then, or when I start a new powder lot, to check it hasn't gone off tune. So far, it just performs, fingers crossed.
     
  9. Laurie

    Laurie

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    I'll have to ask him.

    I agree that there is an increasingly good prima facie argument for yet faster twists. (I've been happily shooting 155.5 Bergers in a 1:10 twist barrel since 2012 at an Sg of 2.39 on my home range, somewhere around 3.25 at Raton in the 2013 FCWC. Many GB FTR competitors have done this for longer still as using the 155.5 Berger and 210 Berger BT as an either/or combination depending on conditions on the day was long popular here. I suspect though that the 200.20X has likely seen that practice off now though except for one very successful guy I know who has shot the 210BT in a 1:10 for as long as I can remember and has no intention of changing, a brief flirtation with the 230 Berger aside.)
     
  10. Ned Ludd

    Ned Ludd Gold $$ Contributor

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    This is exactly what I'm taking about. I feel pretty certain it's an inherent design issue with the bullet. Too many people that know what they're doing have had the exact same experience with different setups for it to be anything else.
     
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  11. D.Stone

    D.Stone

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    Has anyone tried shooting them in a shorter throated chamber? The bearing surface on these bullets is very short, so they might benefit from being supported by the case neck as they go into the rifling.

    I know that the 10 shots I did for a velocity measurement ended up going into a group that was around an inch tall and 2/3 of an inch wide over a 4.5 grain spread of powder at 100 yards.

    When I shot them out to 1710 yards, I saw no reason to believe the bullet was inaccurate, even in a 10 twist barrel. Granted the targets we're generous in height, so I don't think they were particularly hard to hit. Knocking an IPSC at 1350 yards was very easy and could be done as fast as you could load a new round.
     
  12. bbarber25

    bbarber25

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    A 10 twist might stabilize the bullet enough it doesn’t key hole and it shoots well, but you’re probably not getting the most out of the BC, Litz has proven that twist rate affects BC. With a 10 twist you’ll get more pitch and yaw over a 9 twist
     
  13. XTR

    XTR

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    My freebore in the 1:8 is about .120, all of the bullets seat with the bearing surface at least half way down the neck.
     
  14. Archer

    Archer

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    My freebore in the 1:9 Bartlein is .110 and the base of the bullet sits right on the powder charge...I have been considering lengthen it to .125...
     
  15. Ned Ludd

    Ned Ludd Gold $$ Contributor

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    My freebore in a 1:9-twist Bartlein was 0.110". I thought it was just about perfect for the bullet I was using.
     
  16. milanuk

    milanuk Gold $$ Contributor

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    How touchy are these bullets about jump?

    If a person has a 0.170 throat, but jumps 'em 50 thou instead of 10 (which works pretty awesome with 200.20Xs, btw) are they going to 'pattern' instead of 'group'?
     
  17. Jdne5b

    Jdne5b Gold $$ Contributor

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    I shot them at .009 off and .035 off in a long .170. It looked like there may have been another spot >.055, i just never got there.
     
  18. Ned Ludd

    Ned Ludd Gold $$ Contributor

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    My gut feeling tells me it's not a seating depth issue. You can certainly see the effects of changing seating depth on group size, as expected. However, the random flyers are still there.
     
  19. ranger0787

    ranger0787

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    LabRadar data measured at BASF 2/4/2018 at 1311hrs; Kestrel Temp: 79.1, Pressure: 28.31, Humidity: 26%. Data sent through RSI Shooting software. Velocities measured at; muzzle, 1yd, 10yds, 20yds, 30yds, 50yds.

    Sierra #2231 Match King, Lapua Brass, 43.10gr of VV N140 powder yields ES: 9.0, SD: 3.8, Avg Muzzle Velocity 2643.3, G7BC: .3539, with no muzzle brake. Unsure about; bullet length(not my ammo, but my equipment), primers.
     
  20. Quickoz

    Quickoz

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    So has anyone run these in a large match yet? How consistent are they? No weird flyers?
     

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