H4350 load work up - 243 Win.

Discussion in 'Reloading' started by Rmitch223, Feb 12, 2013.

  1. Rmitch223

    Rmitch223 Active Member

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    I've developed a fairly accurate load with my rifle using IMR-4350 and the 105 Amax in my .243 Win.

    I'm switching to H4350 because of less temperature sensitivity.


    I found two pounds of H4350 yesterday locally. So im starting a new load work up.

    What charge weight do you recommend I start my workup at?

    My Hornady manual shows a starting charge weight of 38.3gn and a max of 41gn.

    Hodgdon's data online shows a starting charge weight of 35gn and a max of 37.5 so I'm a little confused as to why they are so much different.

    I'm loading for the 105amax in Lapua brass seated at 2.800" OAL with CCIBR2 Primers.

    Currently I'm preparing to load these five charge weights.
    39gn
    39.5gn
    40gn
    40.5gn
    41gn

    Quickload shows my max pressure if 54,000 at 41gn so I'm fairly comfortable knowing I'm not pushing the limits too much, but the data from the Hogdgon website with a max charge weight of 37.5gn has me second guessing myself. I assume it's because of a different seating depth that was used from the Hodgdon data.

    Am I ok to go ahead with the 5 charge weights I listed above?


    Thanks,

    Ryan
     
  2. tomt

    tomt Well-Known Member

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    Be careful with the longer lenghts and max charge. What Quickload doesn't do is tell you how much "jump" you have. You might be very close to the lands with a COAL of 2.800". Measure the headspace on your brass after loading, take calipers to range and measure headspace after firing each batch. Look at primers, measure headspace, notice bolt lift and felt recoil and make good notes for furture loads. Sometimes the accuracy node is below max. Remember accuracy before speed, the target can't tell if one bullet arrives .003 of a second before the other.

    I'll be interested in your results to load my grandsons .243 win.
     

  3. Rmitch223

    Rmitch223 Active Member

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    with my seating depth of 2.800" Im .018 off the lands.

    Im confused because the starting charge weights vary so much between hodgdon and Hornady.

    Im trying to find a starting charge weight that will be safe but also be close to the accuracy node so that I dont have to waste time, powder and bullets on low charge weights that arent needed for testing.

    I may just go with hornady's starting charge weight of 38.3
     
  4. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    When manuals vary as they do in your case I usually shy away from the combo. It sounds like you can't, so start extra low, no more that mid load(preferably start) in the LOWER book and work it up 'till you hit pressure. The load data is rather worthless here, so you'll be essentially making your own. There was a reason hodgdon was so light on charge, but you won't know 'till you dive in.
     
  5. JackinSD

    JackinSD Well-Known Member

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    My experience with 105 AMAX and H4350 has been exceptional. I am running .15 off the lands. Quite a bit more jump than you are at .018. That is neither here nor there, just a difference to be mentioned.

    I know you have done load development before, but I will hopefully help you out a little. That is a big maybe.

    Looking at your developmental loads, I would decrease the charge distance to .2 from your current .5 grains. Why? I found a great difference in load development (ES and accuracy) with even this small charge distance. Also, it will give you a little more safety in working up to a max load that still hits your accuracy node.

    I went with my middle node, which I found at 39.2gr. I went with the middle node just to give me a little better barrel life and still have decent velocity (2965 avg). I intially used a chrono and 100 yard distance to find accuracy and velocity nodes. I then checked for accuracy at just over 400 yards (407 exactly).

    I found two loads that were very very close to one another in performance(39.8 was the other load). I went with the slightly slower load for the reason described earlier.

    As far as H4350 goes, I have no complaints whatsoever. My load was developed when it was 65 degrees out and has held very true to 10 degrees. I have not done much shooting with this load at hotter temps during the summer. But, my load was made for hunting during the fall/winter. I'll know more once the summer months get here.

    It is always a trial and error process with more errors than not. I hope you find the non-errors.
     
  6. Rmitch223

    Rmitch223 Active Member

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    I was thinking about loading some lower charges at 37gn, 37.5, 38, 38.5, then 39, 39.5, 40, 40.5, 41.

    Just to be safe, most of the people I have talked to say there load is around 41 - 42 grains, but when I saw that hodgdon's max I gotta a little nervous starting my workup at 39gn.

    But then again, If I'm good to go with no pressure issues at a 39gn starting charge I would'nt be wasting time, powder and bullets at those lower charge levels that Hodgdon recommends
     
  7. John Galt

    John Galt Member

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    I would load 1 shot each of the lower charges just to check the for pressure signs.

    My Berger books states that as you increase seating depth you are in effect increasing case capacity and can increase velocity.
     
  8. roninflag

    roninflag Well-Known Member

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    Rmitch- what rifle? what are going to shoot at? are you using a chrono??
     
  9. azsugarbear

    azsugarbear Well-Known Member

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    Rmitch,

    When first working up a load, I start low and then load just one round at either .5 gr. increments (for 243 or 270), or at 1 gr. increments (for 338 Lapua). The purpose of this exercise is to help me identify where my max load is with a particular bullet, powder and barrel combination. Once I start to see pressure signs, I back off 1 or 2 grains from there and that becomes my upper limit. Each rifle is unique as to the max pressure/loads it can tolerate.

    I have a REM model 7 in 243 with a Brux 1-in-8.5 twist barrel shooting the 105 gr. Begrer vld. I tend to run loads on the warm side - and my Brux barrel seems to be a "fast" barrel. I found 42.5 gr. of H4831sc and 41.0 gr. of H4350 both produce outstanding groups. But remember: seating off the lands, lot number of the powder, even the difference in the guilding metal used in the bullet's jacket, will all have a bearing on pressure. That's why we always caution "start low and work up slowly"' Good luck.
     
  10. Rmitch223

    Rmitch223 Active Member

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    Rifle is a Remington 700 SPS Varmint with a 26" barrel/

    I use this rifle for mostly long range target shooting.

    I currently do not have a chrono.

    Here is the Quickload data Ive been looking at.

    37gn seems fairly conservative.

    Second page is the Quickload data at 41gn that I plan on working up to, still seems pretty safe in regards to pressure...?

    [​IMG]

    [​IMG]
     
  11. azsugarbear

    azsugarbear Well-Known Member

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    Your data looks fine. It's time to dive in.
     
  12. jfseaman

    jfseaman Well-Known Member

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    First: I do the 1 round per load increment thing to establish pressure indications and get a feel for velocity. Much more economical to make 10 rounds at 1 each for .3 or .5 grain increments than to make 100 rounds at 10 each and waste those that are no where near the expected or desired velocities. I chron 'em and then I graph the results, I believe the "node" are visible by the predicable increment in velocity just prior to a reduction in the increment or even a reduction in velocity. Explained, If a few loads in the ladder show a 50fps per increment increase in velocity but suddenly drops to say 10fps or even back slides for a couple increments then for me, there seems to be a node at the "peak". Not enough data to make this a method but it helps me keep the round count down during load development.

    I don't have my data book or I would enter a real example to express the above.

    Second: didn't you mean increasing seating depth reduces case capacity and increases velocity?

    FWIW: My A-Maxes and V-Maxes all like to be -.005 to -.010 from the lands but WMMV.
     
  13. tomt

    tomt Well-Known Member

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    Rmitch223,
    What brand of brass are you using? The reason I'm asking is there is a BIG difference in volume from one manufacture to another. For instance a Winchester case has more volume than a Federal. The Win. case will have a lower pressure than the Fed. because of the larger volume.
     
  14. Rmitch223

    Rmitch223 Active Member

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    I'm using Lapua brass. The case capacity is 54.1 grains of H20.