Question for S1

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by mbianchini, Apr 13, 2003.

  1. mbianchini

    mbianchini Well-Known Member

    Messages:
    127
    Joined:
    Dec 3, 2002
    S1 seems to me that your very knowledgeable on the 243 Ackley Imp. 40. I wanted to know if you are having trouble with RL-25 being temperature sensitive in colder weather. I was at the range this Saturday getting ready for the Western PA groundhog shoot here today.
    I was interested if you ever tried N170 or H1000 and what kind of velocity you were getting with those powders and if they were temperature sensitive.
    I was told by two shooters at the shoot that RL-25 works better when its hotter that 75°
    From 60° to 66° there is a big difference in velocity. Any recommendations would be appreciated.

    Rifle configuration.

    243 Ackley Imp. (.271) NK Chamber Reamer from Dave Manson which is throated .075 free bore for the 105 VLDs
    Farley “S” action and Farley 30mm rings.
    2 Krieger 8" twist 28.5" HV,& Lilja 8” twist 29” HV
    Jewell Trigger.
    Leupold 18x40 LR boosted & 1/16 MOA dot on 40x by Premier Reticles
    Dave Bruno did the Chambering of the barrels.
    I did the stock work and the Sikken Viper Race Yellow Paint and clear
    Jewell 1.5oz BR trigger. Bat Machine Stainless Trigger guard
    Shehane McMillan ST-1000 stock from Bill Shehane (D&B Supply)
    Shehane TRACKER polished billet aluminum buttplate
    Weight 16.5 lbs.

    I started shooting at 10:00am the temperature was 60° my load was
    49.0gr RL-25
    Lupua brass
    Federal 210 match primers
    JLK 105s on the lands.

    I was shooting three shot groups through my Oehler P35.

    First. 60°

    3225 fps
    3215
    3214

    Second 62°

    3289 fps
    3255
    3277

    Third 66°
    Dropped powder down to 48gr

    3245fps
    3229
    3237

    [​IMG]
     
  2. Guest

    Guest Guest

    mbianchini,

    I am a big fan of the .243 Imp, and it looks like you have an outstanding rig.

    I have only had problems with one lot of RL-25, lot number 25108 dated Oct. 30 2001

    This powder was faster than any lot of RL-22 (twenty two, no typo) I have ever tested, and the velocity and pressure was all over the map, this stuff was scary.

    The good lots of RL-25 produce the best velocity of any powder we have tested with 105 gr. bullets. The good lots of RL-25 are about 160 fps. faster than H-1000 at equal pressure. RL-25 is more temp sensitive than H-1000, but not near as bad as the ball powders. N170 falls somewhere in between RL-25 and H-1000 in both velocity and temp sensitivity.

    I would look for a good lot of RL-25, I have shot many of the 105 bullets out there, but my favorite load to this day is 51.2 gr. of RL-25 and a 95 berger VLD. The 105 JLK is also outstanding. These two bullets performed well on deer to 600 yards; past that the terminal effect of the 105 A-MAX has shown itself to be superior. [​IMG]
     
  3. Brent

    Brent Well-Known Member

    Messages:
    2,537
    Joined:
    Jun 12, 2001
    mbianchini,

    Looking at your data real closely, I'd guess you shot the first ones from a clean, cold barrel because the velocity is a bit lower, just a guess.

    The next group looks like the barrel was a little bit warmer and moved the pressure up and velocity with it.

    The third group looks like dropping back a grain brought it back down with a more of a stable fouled barrel... again, just a guess.

    Without knowing exactly how you shot these loads, cleaning and all that, it's pretty hard to tell why you got a big spread there.

    RL25 and RL22 have worked great for me, but pressure and velocity is always down for the first couple shots on a clean barrel.

    A 6 degree temp swing isn't nothin, I been shooting this stuff from 10 degrees up to 45 degrees with no noticable change in MV at all.
     
  4. mbianchini

    mbianchini Well-Known Member

    Messages:
    127
    Joined:
    Dec 3, 2002
    S1

    I greatly appreciate the info.
    The lot number is worn off from taking the jug to the range but the date is still there. Dated 07-19-2000 which is a five ponder.

    Brent

    The nine shots that I run through the Oehler P35 were all shot on a cold barrel. Before the nine shots were fired I fouled the barrel with two shots. I was shooting two guns that day so the readings above were in an about a one hour period. Shoot three and let cool.

    Matt