Temp sensitivity of RL powders. Never seems to be a problem with me. WTH?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Michael Eichele, Oct 26, 2012.


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  1. Michael Eichele

    Michael Eichele Well-Known Member

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    I have always read how temp sensitive RL powders are versus H powders. Yet once again I have tried another RL powder in a new (to me) cartridge at extreme temp spreads and find it hard to believe that so many people hate RL powders because they are 'temp' sensitive.

    My favorate line is "oh but they are ok until you get over 90 degrees...then the load becomes a bomb."

    WTH???

    Many of you know that I have recently been working with a 6.5x284. The other day I decided to test RL22's sensitivity to temperature. I had worked up a good load. 53 grains under the 140VLD. Velocity at 2962 on average. Then I decided to test them cold versus hot like I have several other calibers with various types of RL powders.

    Loads were shot at 14 degrees F. and 114 degrees F. It is a total coincidence that they were exactally 100 degrees apart. Rounds were placed in a ziploc bag in the back of my truck with a reliable thermometer over night. At the time of firing it was 14 degrees.

    The other loads had been placed in a bag with another reliable thermometer right on the heater vent on my dash for over 1/2 hour. They were at 60 degrees when they were placed there to begin with. The thermometer had read between 100-114 for quite a while. At the time they were fired, the thermometer read 114 degrees and had been there for a while.

    And the difference was???????????????........

    27 FPS on average with none more than 33. No sticky bolt lift, no blown primers, no nadda. Just a few FPS faster.

    This has been the case for me every time I have tested RL powders. 308 win, 300RUM, 6.5x284, RL-15, RL-19, RL-22, RL-25 take your pick. They have all done very well in the extreme temp differences.

    Sorry for the rant...

    M
     
  2. jimbires

    jimbires Well-Known Member

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    I use RL17 and RL22 . I don't have any big ,or wild , velocity changes changes due to temp changes that I can tell . here is a link I found a few days ago that talks about temp sensitivity , I think you might find interesting . read question # 7 . Jim

    FAQ « Accurate Powders
     
  3. mikebob

    mikebob Well-Known Member

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    I shot rl22 in my 300wm for a long time before i switched to the 210vld. I never had any trouble with it in any temp.
     
  4. bbutturff

    bbutturff Well-Known Member

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    I've never had a temp sensitivity problem with RL-17 or RL-22 in my 300 WSM. For me, in MY rifles, RL-17 performs just like H4350 with the benefit of a few more FPS. I'll be trying them both in my new 325 WSM soon and I expect the results to be the same. As usual, YMMV.

    Bruce
     
  5. 7stw

    7stw Well-Known Member

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    I think that it may be a powder volume , as well as the type. What I mean by that is , I used to use rl22 in a 25-06, and never experienced any performance changes during temp swings. But when using larger magnum cases, approaching or exceeding 90 grains, that's where it seems to show up. ( at least with me anyway).
    I am a fan of the RL series powders as well. I presently use, 19, 22, 25, and 17. Of those powders, the 17 seems to be less sensitive then 19, and 22. I have been doing some work with RL25 in my 7 STW custom. So far, I really like it's performance, and it too seems to be less sensitive, then 22. I still use RL22, in another rifle, and always will. I just know what temps it performs better in, and typically, hunting season is it's zone.
    The RL powders somehow inherited the temp sensitive rep, but I'll keep using them.
     
  6. Scot E

    Scot E Well-Known Member

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    Not sure how this may apply as it sounds like some of your testing has been going on for a while now but I have heard rumors that RL was working on the temperature sensitivity issues.

    Scot E.
     
  7. phorwath

    phorwath Well-Known Member

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    Michael,

    I'm wondering if your rifle was 14F when you chambered the rounds that were 114F. And if so, how long were the rounds in the chamber before you fired them over your chronograph.

    When I've compared cold temperature MV to higher temperature muzzle velocity, I've placed the entire rifle in a freezer so both the rifle chamber and ammo come down to temperature. My higher temperature tests are limited to about 75F room temperature using this approach. But I don't have to worry about how quickly a cold chamber cools down warm ammo or a warm chamber warms up cold ammo before I fire the round over the chronographs.

    I've not shot RL powders very much over my chrono setup and therefore have no first hand data to report. I have spent some time chronographing cold versus warm loads with a few IMR and Hodgdon powders.
     
  8. Michael Eichele

    Michael Eichele Well-Known Member

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    Paul,

    I thought about that ahead of time. The rifle was about 70 degrees when the hot round was fired I assure you that it spent minimal time in the chamber before it was fired.

    The rifle was allowed to cool for five+ minutes before the cold round. Again it spent minimal time in the chamber.

    In the past, I have fired -10 degree rounds out of a -10 degree gun with the same results. Allowed the rifle to warm and fire hot rounds. Results have been consistent so I don't go through the trouble of freezing my rifle unless I am testing cold bore shots with cold ammo.

    M
     
  9. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    Never had any trouble with rl here. I use rl 15, 17, 19, 22, 25, and the new rl33 and so far they've always beat or equaled their single base competition with better velocities in most calibers. I do use some single base, but I usually start with rl to see what the stuff will do. I thought I was having trouble with rl25 in my stw earlier this year but it turns out the rifle needed a pillar bed job because it kept loosening up trigger guard screws.