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Thread: Not having success with 260 Rem

  1. #21
    Boolit Grand Master


    Larry Gibson's Avatar
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    "I think the twist rate is the killer."

    That would be correct. The "odd flyers" are the result of the bullet exceeding it's RPM Threshold. The first load at 1515 fps is running 136,350 rpm....The heavier loads are obviously pushing the RPM over 140,000......
    Last edited by Larry Gibson; 10-08-2018 at 10:49 AM.
    Larry Gibson

    “Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
    ― Nikola Tesla

  2. #22
    Boolit Master

    Rcmaveric's Avatar
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    The 17.6g of Reloader seven was 1690 Avg FPS. I figured it was close to being over rpmd.

    There are a few variables I need to illuminate though. Like sorted brass and double check neck tension. Try and rule out some posibilities.

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  3. #23
    Boolit Man
    RedlegEd's Avatar
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    Range Report

    Hi all. Went to the range today to check out some cast M1 and 260 REM loads. I'll just post the best two of the 260 REM targets using AA5744. There's really no "official" published data on light/reduced loads for this powder and cast bullets, so I interpolated from existing data starting low, and working my way up. Notice the difference from the expected velocity vs the actual. Another reason to never start high. Here are the results.

    Basic Data:
    Rifle: Remington 722, .260 REM, 24" Bbl (make unknown), 1:8" Twist (recently rebored from .22-250)
    Bullet: NOE 266 FNGC, #2 Lyman (mine averaged 141.2gr w/GC & lube), sized 0.266, BAC followed by TL
    Powder: AA5744, no Filler, each load weighed
    Primer: WLRP
    Brass: RP/Starline (stupid me...I mixed them)
    OAL: 2.340 (Comparator), jump 0.03"

    Overall observations: These had a little more "oomph" than the Blue Dot loads, but still easy shooting. Also, the barrel did not tend to heat as quickly (based on measured barrel temp.) I had no pressure signs at the upper limit, but had a few unexplained flyers, so I think I might have exceeded the RMP threshold of the bullet (thanks Larry Gibson.) I also posted a table of all the loads fired so you can see how the AA5744 did in my rifle with these bullets (and mixed brass ...[sigh.]) I believe the best load will be between 13.0 and 13.5gr. If you notice the group locations relative to the aim point, they're right on top of each other.


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    Ed
    Last edited by RedlegEd; 10-23-2018 at 08:22 PM.
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  4. #24
    Boolit Master

    Rcmaveric's Avatar
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    Seams the going consensus is going to be sub 1600 fps. Around 1500 fps puts the bullet in the 800ft lb energy category though which is minimum hunting energy. So its an accurate and useable load.

    External balastic calculator has me usable balastics out to 125 yards. Starts droping like a rock after that.

    Sent from my SM-G950U using Tapatalk
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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check