Do ladder test results tend to xfer to different bullets of same weight?

Discussion in 'Long Range Hunting & Shooting' started by Miller Outdoors, May 9, 2010.

  1. I'm wondering if ladder test results tend to transfer to different brand bullets in the same weight. For instance - I do a ladder test on my 6.5x55 with 140gr sierra gamekings. If I perform the same test with identical powder/OAL, etc. with 140 gr Berger Hunting VLD's will the results tend to be similar showing the same or similar accuracy nodes? Or is that unlikely?

    Also, would 130gr gamekings tend to show a similar ladder test result to the 140 gamekings, or is that unlikely?

    Incidentally, I'm using Lapua brass CCI large rifle primers and RL22 powder .02 off lands, loading the ladders starting at the manual's suggested starting grains and adding .2gr with each step, to two steps past the manual's "never exceed". Of course I'll watch for pressure signs as I go. Do some guns/loads not show pressure signs well past the manual's published "never exceed"? Is it reasonable to keep going with the ladder so long as I don't see excess pressure or should I just stop at "never exceed"?

    Thanks! :)
     
  2. long450

    long450 Well-Known Member

    Messages:
    537
    Joined:
    May 5, 2007
    In my exerience , NO. I believe the reason is due to different bearing surfaces and length for each bullet. You have to do a test for each bullet.
     

  3. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004

    Same here tho' I don't know why.
     
  4. long450

    long450 Well-Known Member

    Messages:
    537
    Joined:
    May 5, 2007
    I did not answer the "never exceed" question. Some rifles do not show pressure signs at the same load ,showing pressure in a different rifle. There are many reasons. Mostly due to different chambers, throats. bore , and rifling style. Be careful working with loads that are at or exceed recommended max. Little changes in the temperature of the ammo can cause big changes in the safe performance.
     
  5. Michael Eichele

    Michael Eichele Well-Known Member

    Messages:
    3,829
    Joined:
    Jan 6, 2003
    I have always had to do ladder tests for the same weight of bullet of a different brand or even style. One example is the 200 SMK versus the 200 SGK. Charge for charge, the velocity was the same. Accuracy was a different story. I have no idea why as the look identical except one has a hollw point and the other has a soft lead nose.

    On the flip side, when I was switching from the 225 ACCUBOND to the 225 SST. Same charge weight, same accuracy however, the SST's are about 52 FPS slower than the ACCUBONDS. Because the accuracy is the same (very good at .4 MOA), I didnt bother trying to match the velocities by changing charge weights.

    Different ogives (land contact), bearing surface, metal alloys, jacket thicknesses, specifec gravities, stability factors etc.......are most likely the cause of these changes.