Accubond LR Comparison and G7 BC Test

Discussion in 'Long Range Hunting & Shooting' started by MMERSS, Jun 9, 2013.

  1. MMERSS

    MMERSS Well-Known Member

    Messages:
    912
    Joined:
    Feb 5, 2013
    A hunting companion called me last week inquiring if I had any luck locating the Long Range AccuBonds (LRAB) for his 7 Rem Mag he recently purchased. "Not yet," I informed him. He has portrayed several times not being comfortable hunting with what he called "exploding" bullets. With the new line of LRABs advertised, he was quite interested in their performance. I informed him I had recently acquired two boxes of the 30 Cal 210 LRAB’s and would be willing to test a few around 1000 yards with the results used to help him with his decision on a direction for a bullet to use in this new rifle. I also was not willing to invest more than 40 total rounds during tests to save barrel life on my rifle.

    With the name Long Range, an appropriate starting point for testing would be with bullet consistency and evaluating the advertised G7 ballistics coefficient. I used the Berger 230 Grain Hybrid Tactical OTM with an advertised G7 BC of .368 for comparison to the LRAB advertised G7 BC of .366.
    LRAB and Berger BC.jpg

    Bullet Comparison.jpg

    Pictured left to right for visual comparison are the 30 cal Berger 230gr Hybrid OTM, 30 cal Nosler 210gr LRAB, 338cal Berger 300gr Hybrid OTM, and 338 cal Nosler 300gr AccuBond.


    I decided to evaluate the LRAB with comparison to the Berger OTM in four areas:
    1. Base to Comparator length.
    2. Weight.
    3. Short range precision to include muzzle velocity variation.
    4. Computer generated G7 BC drop results tested at ranges near 1000 yards specifically for the LRAB. I have shot the OTM’s for the past few years and have confidence in their advertised G1 and G7 BC’s.

    Base to Comparator Length and Weight
    Testing Equipment.jpg

    Twenty bullets each were randomly selected, measured, weighed and placed back into their box. Sorting was not conducted. Length was measured using a Sinclair bullet sorting stand and quick sorting comparator. Weight was measured using a Sartorius M-prove scale.


    Berger OTM
    Average Weight - 230.07 grains
    SD .091 grains
    Average base to comparator length - .789"
    SD .00074"

    LRAB
    Average Weight - 210.31 grains
    SD .221 grains
    Average base to comparator length - .766"
    SD .00078"

    Short Range Precision (Group Size in MOA) and Muzzle Velocity Variation
    At the range.jpg

    Three shot groups were taken with each bullet at 100, 200 and 300 yards. Average group size was measured in MOA. An Oehler M-35p chronograph measured the muzzle velocity of each shot. The rifle used during testing was an accurized Remington 700 LA fitted with a 30" Lilja 1-10" twist barrel chambered with a SAAMI reamer in 300 RUM and skim bedded in an HS Precision stock. A Nightforce 8-32X56 NXS scope with NP-R1 reticle topped the rifle and finished with a Sinclair bipod. Rounds were loaded three grains below estimated MAX charge with an OAL of 3.660" thus allowing just enough room for clearance in the magazine. Free bore was approaching 170 thousandths of an inch for each. Keep in mind load development was not conducted and results could have varied by conducting load development. I was more interested with the muzzle velocity standard deviation results considering the LRAB was not as precise in bullet weight as the Berger’s.
     
    Berger
    Average three shot MOA .64
    Average Muzzle Velocity 2960 ft/s, SD 15 ft/s

    LRAB
    Average three shot MOA .96
    Average Muzzle Velocity 3136 ft/s, SD 11 ft/s

    LRAB G7 BC

    Ten additional LRAB’s were loaded using an estimated MAX charge and zeroed. The four shot average zero muzzle velocity was 3222 ft/s.

    The next morning a target was set up at 960 yards. Adjustments were made for wind and spin drift. Three shots were taken using the advertised G7 BC of .366 utilizing my ballistics engine. The group measured 18" low and 9" in size. 1095 yards.jpg
    Note the vertical.

    The target was then placed at 1095 yards for my last three shots. The first shot hit low just missing the target. I adjusted up 2.25 MOA and fired my last two rounds. The two shot group measured 12" low and was 11" in size. 960 yards.jpg
    Note the vertical.

    The advertised LRAB G7 BC of .366 is significantly above a corrected G7 BC required for my particular firing solution for the ranges noted above.

    Of particular interest is the vertical displacement of the two groups. While two groups do not support near enough data to draw any form of validity, the results look promising. Both LRAB groups additionally measured approximately the same average MOA as in the short range testing while under slight wind and mirage changes (less than 3 MPH). The vertical displacement appears promising. I would consider the LRAB of having the potential of being a formidable long range hunting bullet compared to their current AccuBond design with further tested G7 BC validation and hand load development.
     
  2. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    So what did you need to use for a G7 BC to get your dial ups to come out for these two distances for the LRAB 210?

    Thanks and good work.

    Jeff
     

  3. Michael Eichele

    Michael Eichele Well-Known Member

    Messages:
    3,829
    Joined:
    Jan 6, 2003
    Nice job. Can I ask what your zero was and atmospheric conditions were?
     
  4. MMERSS

    MMERSS Well-Known Member

    Messages:
    912
    Joined:
    Feb 5, 2013
    Sorry typo,

    G7 BC corrected to .321 for solution.
     
    Last edited: Jun 9, 2013
  5. MMERSS

    MMERSS Well-Known Member

    Messages:
    912
    Joined:
    Feb 5, 2013
    Michael,

    I suppose you could say I established a zero 18" low at 960 yards with a DA of 5600. I don't take much validity with my first zero while shooting only a few rounds with groups measuring close to 1 MOA. In either case both ranges produced low shots using the advertised .366 G7 BC. Additional groups at various ranges need to be conducted to accurately predict the BC needed for a solution for my particular rifle and ammo combo. On the positive side, the LRAB's appear to be holding MVV and verticle well!:D
     
  6. bigngreen

    bigngreen Well-Known Member

    Messages:
    5,840
    Joined:
    Nov 24, 2008
    Nice work, thanks for doing it!! It looks like in this case the ALR may have similar ballistics to the Berger 210, it will be interesting to see how long range accuracy holds out over time!
     
  7. etisll40

    etisll40 Well-Known Member

    Messages:
    1,684
    Joined:
    Jan 28, 2009
    Good work.

    Thanks for taking the time to put a pencil to this first shoot.
     
  8. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    Thank you.

    So you never shot the new load and zeroed at 100 or 200? Sorry if I am missing something here.

    Thanks
    Jeff
     
  9. MMERSS

    MMERSS Well-Known Member

    Messages:
    912
    Joined:
    Feb 5, 2013
    Jeff,

    100 yard zero with a few rounds. I would give a "gut feeling" error of +-1/2 MOA. I could have loaded more rounds to confirm however as long as I could hit paper with the first three rounds this would be a more accurate prediction of LR capability and not so much centered around an initial BC input or ballistics solution validation. Additionally, it would have been beneficial to conduct further zero validation and multiple LR drop comparisons. However, I was deliberately conscious of tube round count for what? Simply a starting point and comparison for a friend to consider or not consider the LRAB as a hunting round. I posted the results for the rest of the LR community to view as there is much talk about the LRAB as a capable LR hunting bullet. I'm patiently waiting along with many others with more complete and complex LRAB results.
     
  10. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    Ok, Thanks. So for you they ran with a 210 Berger out to 1000 plus for BC. That is pretty good. I will await more results like you. But for now I am liking the 215 Hybrids with a G7 of .356 pretty good. For what it's worth I have ran them to past 1500 and checked drops. The advertised BC got me there and on drops with only one G7 entry.

    Jeff
     
  11. MMERSS

    MMERSS Well-Known Member

    Messages:
    912
    Joined:
    Feb 5, 2013
    Jeff,

    So far the BC appears to be close to the Berger 210. I don't believe this would be a surprise to many if confirmed. I hope to make your shoot next Saturday and look forward to the opporltunity to formally meet. I was anticipating having to work but not the case. Now I have the perfect excuse to fire form some 308 Lapua brass for my F/TR rifle.
     
  12. JonnyVang

    JonnyVang Active Member

    Messages:
    32
    Joined:
    Jul 8, 2009
    Thank you for testing the bullets long range!
    If these LR Accubonds can keep up with the bc of similar weighted Berger VLDs it will be very nice. I am looking forward testing the 7mm versions when they get available.
     
  13. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,709
    Joined:
    Jan 21, 2008
    Very promising. I'm using a G7 BC of 3.23 for Berger 210's. It will be interesting to see futher tests, and hear how the AB performs on game at long range.
     
  14. jsthntn247

    jsthntn247 Well-Known Member

    Messages:
    661
    Joined:
    Jan 14, 2009
    Since the B.C. is close or equal to the bc of the 210 berger and 208 amax, I see no reason to pay 2x the money for these. The s.d.'s on a 30 cal 210 grain bullet are so high that (in my experience) they don't fragment and explode on contact like lighter 30 cal berger's and amax do, and therefore a bonded bullet with that high of a s.d. is not needed. However, if the 168 grain lrab's have the same b.c. as their Berger counterparts, I do think it would be a great choice for long range hunting and the cost could be justified.