Anybody try these new bullets yet?

Discussion in 'Reloading Forum (All Calibers)' started by Ledd Slinger, Nov 6, 2018.

  1. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    Sierra is coming out with some pretty impressive ultra high BC designs on their revamped Match King line of bullets.
    Been very impressed with the extremely consistent BTO measurements on the new 30 Cal 230gr MK bullets I have (.800 G1 BC)

    Wondering if anyone has conducted any load development with their new 6mm 110gr MK? Another very impressive BC (.617) Thinking these might be a good match for my son's 6mm Creedmoor.

    https://www.sierrabullets.com/store/product.cfm/sn/1575/243-dia-6mm-110-gr-HPBT
     
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  2. STOMP442

    STOMP442 Silver $$ Contributor

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    I am running them in my 6mmXC. They shoot fantastic and the BC seems to be slightly understated. I am having to use an adjusted G7 BC of .315 to get them to match my drops in my applied ballistics program. I am pushing them at 3070fps from a 26" 7.5 twist Proof barrel and 40.0gr of R-16 in Norma cases with CCI LR #200 primers.
     
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  3. Forum Boss

    Forum Boss Administrator

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    PRS Guys Take Note!

    The 6XC will run with a 6mm Creedmoor.
    The new Sierra 110s are very good, and pointed from factory.
    You'll need a 1:7.5" twist for these 110s -- a 1:8" is marginal.
    Reloder 16 is the Real Deal. Great choice for long, heavy 6mm bullets in medium size cartridges.
    Norma 6XC brass is good: $74/100 from http://www.davidtubb.com/xc-brass-norma?search=norma 6xc
     
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  4. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    Nice. Thanks fellas. I've found in the past that Sierra BC's are slightly understated as well. They do a lot of testing at different velocities before releasing a bullet. They are the only manufacturer I know of that lists the adjusted BC's at various speeds. That information can only be obtained from extensive testing.

    Berger "claimed" BC's are good, but I've been shooting their bullets since they first hit the market. I've watched the claimed BC's drop incrementally over the years as they received feedback and complaints and finally got around to actually doing some testing on them. Ive never had to worry about the claimed BC's on Sierra bullets being less than the stated value (tho I haven't fully tested the new MKs).

    As far as factory bullets go, Berger have always given me superior measurement consistency in the past. But after measuring the new 30 Cal 230gr MKs, I think Berger has a real rival to worry about on the commercial market. The new Sierra 230gr MKs are ridiculously consistent from base to ogive. So consistent that they are actually very boring to measure. From the posts above, it sounds like these 6mm 110gr MKs have the same consistency.
     
  5. swd

    swd Yep that's me Gold $$ Contributor

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    I've shot a couple thousand or more 110's. Great bullet. They hold excellent waterline and buck the wind a lot better than 107's at 1K out of my BRX. And the BC at .617 is the real deal.
     
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  6. 1shot

    1shot Site $$ Sponsor

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    I've been running the 110's since they came out with very positive results. 3,115 out of a 7.5 twist Brux 6SLR. They have shot inside every 105 bullet I've used in 10 years.
    I hope this helps,

    Lloyd
     
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  7. Papa Charlie

    Papa Charlie Silver $$ Contributor

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    Just looked at the new specs, I think I will test the Matchking 200 and 230 for my .308. Have been using the Berger Juggernauts with ok results at 2745 fps.
     
  8. r bose

    r bose

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    The new "shape" of bullets coming from Sierra and Nosler (RFD'S) are very intriguing with gains in BC like never seen before. Hornady ELD match bullets not far behind. My opinion is any of these bullets will require a faster twist barrel than what anything comparable in weight did before. Sierra was wise enough to publish a "recommended twist" with their bullets. Nosler didn't and maybe that's why some of us had issues with the RDF's. I shot some 105 RDF's in my 6/250, 8 TW 30" with OK results. Shot them thru my 6XC with a 7.5 TW 30" and boy did they come to life!! Speed out of both rifles is no more than 100 FPS different (just at 3K)

    Berger has lowered their BC's over the years but upped (lowered) the Twist rate also. I never saw where Hornady put a recommended twist on their bullets (or at least on any of the boxes I have) but looking at their website they are starting to. They show a 30 cal 225g ELD Match bullet with a 7 TWIST RATE recommended!!!!! to get the most BC out of the bullet. WOW!!
     
  9. STOMP442

    STOMP442 Silver $$ Contributor

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    If you look at the G7 BC numbers (the number that matters) on the Berger bullets you will see the BCs really haven't changed that much.
     
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  10. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    Yeah that crazy. Who's gonna put a 7 twist on a 30 Cal barrel??? Must have a very long bearing surface or perhaps they they don't know what they are just guessing at it. Not sure there.

    My 300 NMI rifle has a 31" barrel with 1 in 8" twist. Specifically spec'd to stabilize the 230gr Sierra MK at all muzzle velocities. That is the longest 30 Cal bullet I have ever seen. It is significantly longer than the Berger 230gr or 215gr (both of which I also have on hand).

    My son's 6mm Creedmoor is a repeater throated for the 105gr Berger so if the new 110gr is a lot longer, magazine length may be an issue if trying to seat to the lands.
     
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  11. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    The point was Sierra conducts extensive testing before they release a bullet to the market. Their claims are true and they don't ever have to change them. I like Berger bullets and always will. Been using them a very long time now. But I also like a company that does their homework before releasing data to the public.

    Berger also listed the original 6.5mm 140gr VLD (now the "Hunting VLD") as requiring a 1 in 9" twist along with a .640 G1 BC when they first came on the market. We all know now that twist is a little slow and they have since changed it to 1 in 8" along with and adjusted .600 BC (at least the 2nd BC reduction since the start)
     
    Last edited: Nov 7, 2018
  12. STOMP442

    STOMP442 Silver $$ Contributor

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  13. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    Thanks Stomp, I missed that :)
     
  14. STOMP442

    STOMP442 Silver $$ Contributor

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    I'm willing to bet Berger probably does more extensive bullet testing than anyone and does so at long range. Sierra does a great job and I am not knocking them at all but lets realize that at the time those first 6.5 140 VLDs were made Berger was relying on old school technology and a rudimentary computer program to "predict" BCs, same as any other custom bullet maker out there. They were doing the best they could with the technology and procedures available to them. Since that time technology has come a very long ways and testing abilities have improved greatly. I don't think the BCs have actually gone down per say they have just been more accurately measured and Berger has done a great job of letting shooters and consumers know that. Sierra on the other hand still does things the way they always have and still use the antiquated G1 BC values. It works, but Sierra could do well with a little updating themselves.
     
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  15. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    Good point ;)
     
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  16. Ned Ludd

    Ned Ludd Silver $$ Contributor

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    Pretty much any decent bullet manufacturer does extensive testing. The reason Sierra provides velocity-banded G1 BCs has nothing to do with how much they test, and why they choose to stick with the outdated velocity-banded G1-based system is beyond me. With modern bullet designs, G1 BCs and drag curves don't match up perfectly, unless adjusted for velocity. This is because the G1 Standard projectile doesn't match the shape of the bullets we actually shoot very well. In contrast, the G7 Standard projectile shape is a close match with the type of bullets we typically shoot. As a result, G7 BCs generally do not need to be velocity-banded and remain constant over a wide velocity range. Although either type of BC coefficient will give usable results with a good ballistic calculator, I'd much rather work with a single G7 BC value, than have to play around with 2 or 3 velocity-banded values for a single bullet.
     
  17. Mr Underbridge

    Mr Underbridge

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    I think Bryan Litz explained it as them getting better technology to test bullets, i think new doppler or microphone or the combo of to get more precise numbers an over several points in flight so yes they did change their BC because the got better numbers.
    Ill take consistency over incrementally better BC. Bergers seems to be more consistent for me but that is an anecdote and not a statistic.
     
  18. gawga_boy

    gawga_boy

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    I've found the same thing with the 7mm 183s.
     
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  19. KevinThomas

    KevinThomas

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    Ned has it right here. Sierra’s use of multiple BCs was done to essentially “force fit” the G1 drag model to match up with the downrange results of bullets that should properly have used the G7 model. Bill McDonald came up with this approach well over thirty years ago, at a time when only ballisticians even spoke of ballistic coefficients. Given the fact that there are a great many drag models, each appropriate for only a specific range or style of bullet, it seems that the G1 simply became the defacto standard that all manufacturers began using to allow a general comparison between different makes and brands. Not ideal by any means, but it simplified things considerably. It’s only the relatively recent development of personal computers and exterior ballistics programs that has expanded the average shooters ability to a point where the use of the proper drag model is really beneficial to most shooters.

    The use of the wide velocity bands was Bill’s way of seeing what the bullet would be dealing with in a wide range of speeds, and adjusting the BC accordingly so that the real-world results would more accurately match up with what the shooter was seeing in the program’s predictions. Frankly, we’re in a transitionary point right now where enough of the shooting population has an understanding of the principles of BC that it makes sense to start winnowing down the use of the G1 for everything approach,and start using the G1 where appropriate, the G5 where appropriate, the G7 for modern streamlined HPBT designs and so on.
     
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  20. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    I do calculate my drops using the G7 with Berger bullets and it does indeed give me more accurate feedback on predicted elevation correction than using the G1. Just that the G1 is the only comparison there really is when looking at Sierra vs. Berger. Hopefully Sierra will adopt the G7 as well in the near future.
     

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