Developing my first rifle loads using OCW and Ladder tests

[Embryo]

What amount of vertical spread is considered a minimum when running a ladder test? I am developing my first rifle load(7.62x35) and it is definitely a shorter range cartridge in comparison to what is being discussed here most of the time. I have an idea of velocities with my powder spread and the vertical dispersion would roughly result in 12"@300yd, 27"@400yd, and 48"@500yd. There would be 21 shots in the complete test, 3 sets of 7 cartridges loaded in .2 increments between 16.6-17.8 grains.

I also have another 28 rounds, 4 sets of 7 cartridges loaded to perform the OCW test using the same 16.6-17.8 grain spread as above. I'm sure the rifle will shoot MOA off the bat, probably a bit better. Would it make interpretation of the OCW information easier if the normal 100yd distance was extended out to 200yd?

As you can probably tell I am a bit new to the rifle side of the reloading thing. If you have something to add I would love to hear it. Tomorrow night I am picking up the new optic and shooting these tests Saturday if the weather holds out. Thanks, Evan

 

[mdmp5]

I'm not sure what you are asking. The spreads you posted are quite large. With these tests, you are looking for a couple of charges that are close to one another vertically

 

[Embryo]

If I shoot the ladder at 200yd my 21 shot group would roughly cover 4" of vertical on the target from the fastest to slowest. If I extend my distance to 500yd my 21 shot group would roughly cover 48" of vertical on the target from fastest to slowest. I imagine that 21 shots in a 4" spread would get clustered and make data interpretation tough, and likewise the 48" spread might be a bit much. In the simplest terms, I am trying to figure out how much of vertical target spread is desired and then pick my ladder test distance from that based on my rough ballistics.

 

[steve123]

For the vertical spread your rifle I'd do 300Y.

My bolt guns are usually 6" of spread at 300Y. Where the nodes are the vertical is around a inch.

 

[doctordoctor]

I personally use 300 or 400 but I am going to try the OCW so I will only need a 100 yards. Pick your poison I suppose.