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Creeping up on a hot load of SR4756 and 155 JHP

Discussion in '10mm Reloading Forum' started by jeffreybehr, Jul 31, 2010.

  1. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    Here's another of those high-powder-charge loads from the apparently-old Hornady data published in One Book / One Caliber--11.4g. for 1400FPS from a 5" barrel. Just to reinforce my opinion that there's no such thing as one maximum load for one particular combination, Hodgdon lists only 8.5g. maximum for 1310FPS, and Sierra lists 9.9g. for only 1250FPS with their 150g. JHP bullet.

    Have crept up to 10.7g. for mid-1300s velocity*, still with rounded primers and tight pockets; will shoot more today. A lighter load displayed very low muzzleflash, and 10-odd grains is lightly compressed for stable position in the case, so this one's encouraging.


    * sample was small and not statistically reliable
     
    Last edited: Aug 2, 2010
  2. _The_Shadow

    _The_Shadow Ret. Fireman

    4,520
    21
    Jul 23, 2007
    Southeast, LoUiSiAna
    I have often wanted to try the IMR4756 but never purchased any yet! It does seem to be a good performer in many calibers.
     


  3. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    Things are indeed looking up. The 10.7g. load produced just under 1350FPS (5.15" barrel, chrono screens centered at 10') while 10.9g. produced just over 1350FPS, both with low standard deviation. While primers are still radiused and pockets are still tight, 1350FPS is plenty 'nuff for me, so here's where I quit. (Well maybe I'll try a whole-number 11 grains. :embarassed: )

    Will try to fotograf muzzleflash soon and add to my collection at http://jeffreybehr.zenfolio.com/p548446203/h13f95b3e#h13f95b3e .
     
    Last edited: Aug 2, 2010
  4. SimonovsDog

    SimonovsDog

    55
    0
    Sep 27, 2009
    I tried 10.5gr of IMR 4756 with 155gr XTPs. There were no signs of adverse pressure, but accuracy was terrible. I have since stopped using this powder. I am using a Std Length Bar-Sto barrel in my M20.
     
    Last edited: Jul 31, 2010
  5. alpha6164

    alpha6164 alpha6164

    25
    0
    Feb 16, 2009
    Jacksonville, FL
    Jeffrey,

    Which 155gr JHP are you using for this load? Also have you noticed what Simon says as far as accuracy problems?
     
  6. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    For all my muzzleflash loads and also 'creeping up' loads with 4756, I used Montana Gold JHPs.

    I'm now testing accuracy of an 11-grain load of 4756 v. my PD load of A9. Preliminary results yesterday showed the accuracy of the 4756 load to be close enough to that of the A9 load. Will be shooting more this afternoon.
     
  7. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    Final results for my PD load--while the loads using Accurate9 were slightly more accurate, the loads using 11g. of SR4756 and XTP 155s were plenty accurate enough, so I'm now carrying the 4756 loads.

    11g. will produce c. 1360FPS at 10' from my 5.15" barrel and with VERY little muzzleflash, so I'm happy.

    BTW I received the 500 cases from starline, so I've now bought 1750 new cases!* Maybe I'll never reload a 10mm case again!


    * It's no wonder my wife calls me Mr. Excess. :upeyes:
     
    Last edited: Aug 3, 2010
  8. alpha6164

    alpha6164 alpha6164

    25
    0
    Feb 16, 2009
    Jacksonville, FL

    Is that velocity a typo? You mentioned in the thread before that 10.9g gave you 1350ft/sec.
     
  9. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    Yes it was; TY.
     
  10. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    I finally got north to chrono that 11-grain load.

    CED M2 chrono, screens centered 10' from gun, elevation c. 3000', temp about 100dF, velocity 1385FPS average from a 13-shot sample, SD 14.
     
  11. SimonovsDog

    SimonovsDog

    55
    0
    Sep 27, 2009
    Jeff, what is the COAL for your SR4756 loads. I loaded mine to 1.255+/- .001. I don't know why my groups are opened up so much. I know it's not the barrel. I have other loads that are real stackers!
     
    Last edited: Aug 5, 2010
  12. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    About the same as yours...1.2555 - 1.259".

    What's a 'stacker'?
     
  13. chippy

    chippy

    77
    0
    Jun 21, 2010
    Montana

    One hole on top of another !
    A very good thing....:cool:
     
  14. JayAlonG2910mm

    JayAlonG2910mm

    19
    0
    Mar 28, 2010
    Very interesting!


    What are the recoil characteristics like at 10.5g to 11g?
     
  15. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA
    I find as I shoot more that I'm becoming less sensitive to recoil. When I shoot my 3 Glocks in one session, I can definitely feel the lower recoild of the GAP, but there's little difference between the 357SIG and the 10. I find the recoil to be substantial but highly manageable. I expect more-experienced and -skillful shooters would be able characterize its recoil much better than I.
     
  16. JayAlonG2910mm

    JayAlonG2910mm

    19
    0
    Mar 28, 2010
    How do you think SR4756 would work with a 180g-200g bullet?

    I am thinking about SR4756, Clays Universal, or AA #9 with a 180-200XTP with low flash and around 1100fps from my G-29.
     
  17. SimonovsDog

    SimonovsDog

    55
    0
    Sep 27, 2009
    Yes, What Chippy said!:cool:
     
  18. SimonovsDog

    SimonovsDog

    55
    0
    Sep 27, 2009
    It seems I was wrong about SR4756 and accuracy. I went shooting this weekend and brought along my remaining loads of 155gr XTP on top of 10.5gr of IMR SR4756. The first time I tried this load, it was all over the target at 15yrds. This weekend was a different story. The only change I made was using a 22lb Wolff recoil spring instead of the standard 17lb spring. Accuracy this time was superb! I didn't stack any shots, but most rounds were touching. Maybe the first time I ran this load I was tired, or maybe the spring had something to do with it.
     
    Last edited: Aug 9, 2010
  19. jeffreybehr

    jeffreybehr Silver Member

    765
    3
    Mar 14, 2009
    Phoenix, AZ USA

    Hodgdon lists a SR4756 load with the 180 Sierra, 7.6g. for 1155FPS @ 34,400PSI, the same pressure as their 155g. load of 8.5g. for 1310FPS, so I assume the two are equally conservative.

    I'd choose 4756 and A9 over Universal, which IMO is rather fast-burning for 180g. bullets. And now that I reread that you're loading for a short barrel, I'd start with 4756.