Why does OCW have to be at 100 yards

[lash]

The QB barrel time matched up with the 29.5" 260 average velocity spot on. For the 26" 6.5x284 it was not a good indicator (off by .054 milliseconds )

BTW, I was shooting at 100 yards, lol.

260, 41.7 AA4350, 136 Scenar-L, CCI BR2, 2795 MV, SD=5, ES=13

6.5x284, 51.0 H4831sc, 142 SMK, CCI BR2, 2788 MV, SD=5, ES=14

I like my 136 Scenar-Ls and suggest either dropping them down to 2750, which they like from a 26" barrel or bumping them to 42 or so grains, which is another nice spot. I'm going to go radical and say that the very low SD is what I want when shooting for ELR distances, like 1200-1600 with that load, but I'm fine with something in the range of 9-11 or so SD while shooting most PRS style matches. As the potential error involved with compromised positions is greater than any minor variation introduced by an SD in that range.

 

[Deleted member 10043]

The 260 with the Scenar L is a 29.5" barrel. But you are spot on. My other favorite spot was at 42.3 grains. Also, I got these just using standard dies and I pulled out my magnetospeed and dusted it off. I don't normally see these sort of SD and ES numbers. I also don't normally spend two hours shooting off only 60 rounds when I have the range to myself. It also took me forever to carefully load up for testing. I'm normally a little more sloppy reloading and shooting. More like SD= 9-12 and ES more like 25. This will get me a little more or less than 1 moa at distance on a windy day. But it was a learning experience. I was guilty of contempt prior to investigation. There is something to this and it does save time and ammo in the long run.

 

[morganlamprecht]

Hah, I do shoot, but I am addicted to researching everything I do. I'm not saying that ES and SD are the only thing to look at when developing a load, but 99% of the time, a good load will have a low ES/SD. I personally like the OCW method but I can't discount the chronograph method either. If you could afford a labradar, you could basically run both tests at the same time and get the best of both worlds. I would love to see more empirical research on a lot of this stuff but I'm sure it would cost a lot of money and have very little return value, monetarily.

my buddy uses my load dev steps and runs the OCW portion with a lab radar...he sends me all of this load dev pics and data to confirm what hes thinking of the results...the OCW and lowest ES/SD dont always align...he does however use the highest quality everything, is very meticulous, and his ES is always less than 20 regardless of charge weight...he has at least 3 prs wins this year with a handful of top 10s...the loads that get picked are based on POI at 100...not the velocities