Ladder testing my VSF & VTR 300WSM and 308

Discussion in 'Extreme Long Range Hunting & Shooting (ELR)' started by MagTen, Sep 29, 2018.

  1. MagTen

    MagTen Well-Known Member

    Messages:
    135
    Joined:
    Feb 17, 2012
    Ladder test Rem M700VSF heavy fluted stainless 308 converted to 300WSM with 1 and 12 twist. 100 yard distance.
    Be prepared to get your feeling hurt. Sorry for that. Here is my opinion.
    It has been stated that others shooting their rifles at 100 yards and moving to 200 yards often show different results as to group sizes and I agree. The law of physics indicates that a bullets flight is mostly straight. If it is off 1/4" @ 100 is should be off 1/2" at 200 and so on. I am aware that bullet stability beyond 200-300 yards out to 1000 or more is critical and changes the impact at those distances. Let's forget these distances.
    Let's talk about 100-200 yards and most of you seasoned shoots are beyond my thinking so bear in mind I'm learning even after 50 years of shooting.
    Several issues I want to address:
    1) Some say a certain will not shoot well with the gun/bullet I am using. Out of the hundreds of powders available today this may be true. Out of the hundreds there are only a few that is recommended or loadings listed for your cartridge. Let's say you like Hodgdon Powder. Like me you picked out a starting load and choose 5 different grainage and you found those 5 different loadings gave you no better that 1 1/4" groups and thus you decided that powder was not for you... WRONG
    Only when I started ladder testing each powder have I learned that after using 1/2 dozen recommended powders that almost all powders (mind you that are recommended) will give you a couple sweet spots that will most likely give you fairly good groups. I have found that it takes testing each powder in .10 grain increments to truly test for the sweet spots.
    Once I have narrowed down several brand bullets/weights and powder that is giving me the best groups I will then start working with bullet seating depths.
    I may have simplified what it takes to get good groups with all powders used and I do realize that many other things play into good groups. Barrel quality, twist rate matchup with bullet weights & quality of the shooter.
    The final issue I would like to touch on. I have heard it said that a shooter has seen his groups give certain results at 100 yards and get better or tighten up at 200-300 or more yards. My personal opinion is that this is partially impossible. Remember this: there are other factors that would make it appear that your groups did tighten. The physics of bullet flight is almost certainly effected by speed, bullet stability, (remember we are just talking about 100-250 yards), the shooters ability to hold on target, twist rate, etc. The way you SEE the target at 200 verses 100 may be the cause of your tighter groups. If your gun, twist rate and velocity are all matched you do not have a bullet stability problem. Now it is a different story at extra long range and we are not talking to those folks. I weather is calm and your gun/bullet dynamics are correct your bullet can not change course which it would have to do to get better groups at 200 vs. 100. Think about it and please give us your experiences.

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  2. Dog Rocket

    Dog Rocket Well-Known Member

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    Mar 17, 2018
    As far as groups being tighter in terms of MOA at 200 vs 100, it can happen. Most of the time it is due to parallax. Most scopes with fixed parallax are set at the factory at 200 yds.

    Bullet seating depth changes barrel timing, and therefore barrel / load tune, much more than small increments in powder charge. You would do just as well to pick a safe load that is within the velocity window you want and tune seating depth.

    I start with a load that is 2% under max as determined by my chronograph and pressure signs in MY RIFLE. This gives me headroom for heat. I start with the absolute longest overall length I can stand (this could be due to throat length, magazine length, feed reliability, etc..) and adjust seating depth shorter in .005" increments. I've never had to go more than .045" till I found a depth that gave me acceptable groups.
     
  3. MagTen

    MagTen Well-Known Member

    Messages:
    135
    Joined:
    Feb 17, 2012
    Thanks for your comments. My plan is now to pick 4 of the tightest groups and ladder test them with 5 shots each and chrony them. I'll narrow a bit more. I am taking both my VSF & VTR to my gunsmith next week. He has just received a tool that accurately measures my chambers and record seating depths for each bullet I plan to shoot.