338 Allen Xpress, RL33 load development

Discussion in 'Long Range Hunting & Shooting' started by Fiftydriver, Sep 4, 2013.

  1. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I know lots of guys have been wanting to see these results so wanted to get some numbers up on a post.

    First off, base line information. Rifle that these loads were tested is a Friend/customers rifle that he was willing to run some test loads through. It is one of my Raptor Stalker Hybrid rifles with 28" Lilja barrel. Standard 1-10 twist

    This rifles current preferred load is 99.0 gr of Retumbo under a 300 gr Berger Hybrid seated to 3.866" OAL with an average velocity of 2902 fps. This load is not a red line load as far as pressure goes, just a good top end working load. With this load, just the FAINTEST of ejector ring shadow lines on the case head after firing so this is where I would load the RL33 to to see the same extremely faint, nearly ghost rings on the case head to give a somewhat accurate comparision between pressures of these two loads.

    With RL33, knowing that it was a bit slower then Retumbo, I started at the same 99.0 gr charge but seated the bullet 70 thou off the lands just to flatten the pressure spike on the first firing just in case there was a bit more pressure then I was expecting. THERE WAS NOT!!! At 99.0 gr, RL33 produced a very mild 2789 fps velocity.

    Worked up from there. Next firing I seated the bullets out to 3.865" which is roughly 10 thou off the lands and increased only 1 grain to 100.0 gr. This produced 2886 fps which I am sure most of which was from seating the bullet closer to the lands. Now I had a safe starting point and would not be surprised by any unexpected pressure spikes.

    Here are the results from the entire test. Again, I increased powder charge until just the faintest ejector ring could be spotted on the case head with very close inspection.

    100.0 gr......................2886 fps
    102.0 gr......................2923 fps Already topped retumbo load in velocity
    104.0 gr......................2969 fps
    105.0 gr......................3003 fps
    106.0 gr......................3036 fps 100% load density

    106.0 gr produced the very first hints of an ejector ring so I stopped there. Please keep in mind that the bolt lift was effortless and extraction perfect. This is a very comfortable load but stopped here because it was showing same signs on the case head as the Retumbo load did. I have no doubt that a couple grains more powder would have produced nearly 3100 fps and still had no problem with any primer pocket loosening of any kind but this test was more to find a comparision between retumbo and RL33 in the 338 AX and I believe the results speak for themselves.

    it takes 7 grains more powder but RL33 also offers +130 fps more velocity as well as Retumbo. In reality, I have never been wanting for more then Retumbo can produce. Max loads with Retumbo in my 338 AX chambered in my full size Raptor LRSS rifles produces 3000 fps but it would appear that RL33 will easily produce an estimated 3100 fps or slightly more in the Raptor LRSS 30" barrel length with conventional throat.

    To that point. Again, the throat length in this test rifle is not terribly long but todays standards. As an example, with the 106.0 gr load, which was 100% load density with the 3.865" OAL seating length, I seated a bullet to 4.050" OAL and showed the customer how much added case capacity can be had just by cutting the throat an extra 0.185" deeper. The increase is significant and would easily allow 110 grains capacity with this powder and judging by the pressures produces with these test loads, I am sure that 110 gr would be plenty safe and comfortable pressure wise with a throat cut to allow a 4.050" OAL.

    I would estimate that even in this relatively short barrel length of 28", with a 4.050" throat, that we would see 3100 fps pretty easily.

    All this out of a Lilja barrel which are amazing for accuracy but its no secret that they tend to run a bit on the slower side of average compared to the cut rifled barrels out there. Still, they show up pretty much without a need for barrel break in right out of the box and are great shooting barrels so that's why I use them so much. There is more easy velocity to be had with other barrels but to me, just not all that important to get another 30 fps when I have such a good working relationship with Dan and his crew.

    All in all, very impressed with RL33 in the 338 Allen Xpress. Looking a the load data and seeing that we hit our pressure goals right at 100% load density, that tells me that this powder may be at least as good or even better with bullet weights in the 250 to 265 gr range as well. In this rifle however, looks like a solid 130 fps over Retumbo with what appears to be identical chamber pressures.

    I have heard claims of 150 to up to 300 fps more velocity using this powder over other older powders. I was not expecting that over Retumbo. Magic just does not happen when internal ballistics is concerned, however, getting an extra +100 fps just with a simple powder change is most impressive.

    More external ballistic testing needs to be done but so far very impressed. Looks like a had powder to beat.

    I also believe that as good as RL33 is with the 338 Allen Xpress, it may be even better in my 300 Allen Xpress with the 230 and 240 gr bullet weights. May also be great in my 7mm Allen Magnum with 160-175 and 180 gr bullets. All will be tested soon.

    So far, very impressed. One thing I like a lot about this powder is its small granular size. No larger then Retumbo, in fact it seems even smaller in diameter and possibly even a bit shorter in length. MUCH smaller then RL50, H-50BMG and dramatically smaller then the VV 500 series powders. I like that for flow characteristics with smaller caliber wildcats (7mm Allen Magnum) and for higher load densities.

    More to come but so far definitely a winner in the 338 AX.
     
  2. jmden

    jmden Well-Known Member

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    Thank you, Kirby. Hopefully you can get some more RL33 in and test it in other rifles as well and check ES, accuracy/precision and see how temp stable you think it is. Again, thanks for the report.
     

  3. Kiwi Greg

    Kiwi Greg Well-Known Member

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    Kirby in regard to the 7mm, RL 33 gave me a solid 100fps gain over Retumbo in my 7-375 Ruger with 162 Amaxs, I do have spare case capacity with the Retumbo load.

    It also gave impressive gains with the Berger 250 EH in my 338 Terminator, giving it similar ballistic performance levels to the 300 EH.

    Looking forward to veiwing more of your data, thanks for sharing :)
     
  4. B23

    B23 Well-Known Member

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    Kirby, would your best guess put RL33 closer in burn rate to US869 than it is to Retumbo??

    I bought a 8lb jug of RL33 last winter when it first hit the shelves but as of yet I haven't used any. As you know, I'm a fan of US869 but your testing results have sparked my interest and if I can use less powder, have it burn cleaner and get better FPS as well as ES numbers, why wouldn't I want to give it a try. My 338 Lap Imp has a bit longer throat than your tester does. Mine isn't all the way out to 4.050, I'm at 4.010 and that's 10thou off from touching. Do you think 106gr of RL33 at 4.010 ( ten off) would be ok to start???

    I may have to fill a few cases with RL33, cap them off with 300gr Bergers and strap the Magnetospeed on and see what happens.

    This powder could make the 300AX you built us and even hotter hot rod. With her longish throat and US869 it's currently running 3250's pretty easy. Could be very interesting to see what RL33 does in it. Thoughts????
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Seeing these results, I will order more in.
     
  6. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I think it will get me around 100 fps more as well in my 7mm AM so pretty excited, until I prove this, just wishful thinking!!! I am going to form up a fresh batch of brass for my old 7mm AM. The brass I have been using is 8 years old and has around 7 firings per case on it so makes it a bit harder to read pressures clearly. Will get a new batch formed up and see what RL33 will do in the big 7mm.
     
  7. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    RL33 is not nearly as slow as US869. I would say, from my limited work with it so far in the 338 Raptor where I used Retumbo, H-50BMG and US869 all together in the same cartridge so I can compare them to RL33 which was also tested in the Raptor that the burn rate would be:

    Retumbo
    RL33
    H50BMG
    RL50
    US869
    WC860

    I would say that RL is closer to H-50BMG then it is to Retumbo but nowhere near as slow as US869.

    I would probably start at 100 grains and work up, this will be a very mild load but still, would rather be safe then sorry. If you see no pressure sign, jump up 2 grains at a time until you hit your current load with Retumbo but I would still sleep better knowing you started a bit lower, even with your longer throat length.

    I hate to use the term magical but I do think in the 300 AX, it may be even more impressive then it is in the 338 AX. Time will tell. Now I just have to find some of that elusive time!!!:D
     
  8. MMERSS

    MMERSS Well-Known Member

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    Kirby,

    Thanks for testing and great post. The results of +100 fps over Retumbo are not a surprise. Do you have any plans with testing RL-33 for possible temperature regression computations? Upper 80's in the late afternoons and cooling off in the mornings for this weekend. Retumbo Extreme powder MV regression comparison to RL-33???
     
  9. MontanaRifleman

    MontanaRifleman Well-Known Member

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    I hope you're right about the big 300's, I have visions of 230 Hybrids @ 3200 fps + out of my RUM :rolleyes::D
     
  10. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Its on the TO DO list but so are 30 customer rifles and they get priority so will get testing done when I can. This time of year is hard to do much of my personal testing so if I can combine it with testing customers rifles I can kill a couple birds with one stone.

    its in the plans though.
     
  11. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    What is your barrel length? I am currently getting 3325 fps out of my 300 AX in my Raptor LRSS with 30" barrel length using Retumbo with the 230 gr Hybrid. The 240s go around 3250 fps but they have a much longer baring surface compared to the Berger.

    I would think that 3200 fps with RL33 will be very practical in the big RUM.
     
  12. MontanaRifleman

    MontanaRifleman Well-Known Member

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    It's a 5C Broughton, only 27" long for mobility. I am having it nitrided so hoping for a little velocity gain there as well. I'm guessing my case capacity, based on some other reports, to be right about 99-100%. 3325 is smoking.
     
  13. TXAoudadKlr

    TXAoudadKlr Well-Known Member

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    Can't wait to see the results out of the 300AX.
     
  14. AZShooter

    AZShooter Well-Known Member

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    Thanks for the information Kirby. This confirms the data I gathered over a year ago with smaller cartridges. RL-33 with its longer burning curve yielded higher velocities than max loads of RL-25 or Retumbo.

    The 6mm-284:
    58 gr of Retumbo, 105 Berger target hybrid seated .065" off rifling vel 3307 fps
    64 gr of RL-33 same data for bullet........................................... vel 3485 fps

    257 Weatherby:
    moly coated 110 accubond, .015" off rifling.

    Original load 75.5 gr of RL-25 vel 3615 fps
    84.5 gr of RL-33 vel 3735 fps



    I have no earlier powder comparison for 300 RUM but did get good results in both accuracy and velocity.

    I wanted to shoot the 230 berger match target hybrid but current barrel didn't have correct twist. I rechambered a 24" ss rem takeoff and worked up to 102 gr of RL-33 which showed the beginnings of pressure. Dropped to 100 gr for velocity of 2975 fps. Not bad for such a short barrel.

    Keep up the testing. Many of us are interested.

    Ross