ES/SD and or ladder test

[limbic]

I'm soon to begin a new ladder test with a new 6brx barrel. My question is what happens when you find a good strictly horizontal load and a poor es/sd?

In my old barrel my go to load was 34.3g of 550. 2's and 3's at 100 yards. Usually did well at 300-600 for FCLASS as well. I kinda stumbled across this and did do a true ladder test to see how well it worked. The Es was 6-15 on average but sometimes worse depending on the quality of the brass and the stiffness of the brass. Atleast that is what I attribute the occasional ES of 20-30 to.

How do yall correlate the two? Ignore one or put more weight on one or the other?

 

[Terry]

ES and SD equal vertical at 600 yards. Run your ballistics program and see the difference is a 50fps spread at 600 yards. If all you ever shoot is 100 yards it does not matter. For long range shooting move your test to longer ranges.
Happy Testing

 

[RonAKA]

My thoughts are that it is two different issues. Use the ladder test to minimize vertical at 300 meters. That gives you a basic velocity to work with. Next tweak seating depth, etc. to minimize SD. I think SD is a better measure than ES. SD has predictive qualities for future shots, while ES is a post mortum on the shots you have already taken.

 

[limbic]

That's what I figured. I'll let y'all know how it turns out.

 

[bozo699]

My thoughts are that it is two different issues. Use the ladder test to minimize vertical at 300 meters. That gives you a basic velocity to work with. Next tweak seating depth, etc. to minimize SD. I think SD is a better measure than ES. SD has predictive qualities for future shots, while ES is a post mortum on the shots you have already taken.

Well put Ron, I agree
Wayne