OCW Help



  • I'm looking for help in interpreting my OCW test for my Mausingfield 6.5 Creedmoor with 140 Berger HVLD, and IMR 4451.
    I know you're only supposed to shoot 3 shots, but I shoot 4, figuring I'm going to throw 1 per group.
    I've number my shots. I didn't have much for pressure at 42.7, but at 43, my groups really widened up vertically. On the 4th 42.7 shot, I somehow got the bullet stuck, and when I ejected it, it hit the concrete and dumped all the powder out. Not sure if I got it stuck in the lands or what, so that is why the 4th is not there.

    I'm would like to narrow it down to get my final load charge, then do an OSD test. But I'm not sure where to start.
    It looks like I may have a node around 40.6, and then again between 42.1 and 42.7.

    Anyone want to give any input. I was about .020 off the lands for this test.

    65CM_OCW_01a_zpsm3nzfxi5.jpg

    65CM_OCW_02a_zpsjcuoixtu.jpg



  • Very difficult target to read. Lots of shooter induced or ammo induced flyers there. The larger the groups, the less weight they carry in the overall picture. However, if I were pressed to call a node... it would be one at 40.9, and another one at 42.1 The groups on either side of those are basically right at the same level, give or take a couple shots. I'd focus on 40.9. The low node is almost always going to be more stable.



  • Thanks @orkan. I'm sure they are shooter induced flyers.
    Should I load from 40.6 to 41.2 in .1gr implements to see if anything tightens up? And possibly again from 41.8 to 42.4? Or where would you go from here?



  • Your node is showing from 40.6 to 41.2. Anchor right in the very middle of that at 40.9, and then run an OSD test.



  • @orkan Thanks Greg. I'll give that a try.



  • Not to shift the focus of your thread, but how do you like that Mausingfield?
    I've got a surgeon I'm going to ship off to @tscustoms tomorrow, but I'm interested in trying a Mausingfield for the next one.

    RLTW
    (This space for rent)

    0


  • I agree with Greg, but I would also take 40.9 and and 42.1 and run seating depth with each. Once you find the best seating depth with each, see if one of the two charge weights stand out. If they seem pretty similar, I would chrono and let the SD decide the champion.



  • @ragnarnar said:

    Not to shift the focus of your thread, but how do you like that Mausingfield?
    I've got a surgeon I'm going to ship off to @tscustoms tomorrow, but I'm interested in trying a Mausingfield for the next one.

    I like it quite a bit. Easy to change barrels with the savage nut. The action is very smooth. However, This is my only custom/top of the line action vs an LRI Rem 700 I sold, so I don't really know how it compares to the other custom actions. It is quite a bit nicer then the LRI Rem 700 I had.

    I'm am working on saving up to buy a DTA, but that probably won't be until after the 1st of the year.



  • @pizfiz said:

    I agree with Greg, but I would also take 40.9 and and 42.1 and run seating depth with each. Once you find the best seating depth with each, see if one of the two charge weights stand out. If they seem pretty similar, I would chrono and let the SD decide the champion.

    I disagree. The most stable node is always going to be the "champion." If SD isn't where you want it, then typically component changes are required, if it's not caused by reloading technique.



  • @orkan said:

    @pizfiz said:

    I agree with Greg, but I would also take 40.9 and and 42.1 and run seating depth with each. Once you find the best seating depth with each, see if one of the two charge weights stand out. If they seem pretty similar, I would chrono and let the SD decide the champion.

    I disagree. The most stable node is always going to be the "champion." If SD isn't where you want it, then typically component changes are required, if it's not caused by reloading technique.

    Hey Greg, when you say most stable, could you define that?

    Thanks



  • @pizfiz said:

    Hey Greg, when you say most stable, could you define that?

    Thanks

    Exactly what it sounds like... stable. Least likely to have some random event cause it to fall out of the node. The whole reason we do load development is to ensure that changes in component consistency, bore condition, environmental conditions, not holding your mouth correctly... do not cause rounds to scatter unpredictably.

    Think of it as a window. In the window its open, and anywhere in there is going to result in the bullet going where it's suppose to. On either side of the window... walls... unpredictable bullet behavior. A finicky rifle, with a super narrow node, could be pulled out of the node by a 10 degree temperature swing... or shoot good on rounds 20-50, but fall out of the node for any other rounds fired, or a tiny neck tension variation, etc.



  • @orkan

    Ok, I understand, as its why OCW testing is a great way to find those nodes.
    I guess what was confusing to me, and maybe what I understand better now, is that SD has nothing to do with the quality of the node itself. I was under the impression that Dan Newberry said that good nodes, almost always had the best SD's as well. But your point makes more sense as it probably is most likely in components.



  • Components, as well as the technique used to assemble them. You would not believe how big a difference seating with a hand primer versus seating with the CPS can have on SD.

    Don't get me wrong, low SD is good... but a consistent node is not dependent upon it. I think Dan is probably right, in that loads from a true OCW node tend to offer low SD as well.


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