Thread: Trying something, Eric Cortina method of load development

Originally Posted by MMC3

Soooo, some results...

"Inconclusive" would be the one-word summary. Maybe my expectations were a bit high, but I'll need to do a bit more testing. A couple of good groups, but not yet Cortina's 'wide-node' of two consecutive small groups. In the end I did 8 different seating depths, in 0.003" increments (one was a 0.004" increment). All were seated with a Forster press-mounted die (it seems to give me the lowest run-out) to 2.190", measured with a Hornady gauge thingy. Then I seated to depth with a Wilson micrometer hand-die at the range, and measured each one.

Attachment 157811

I'm thinking I'll now try two steps closer to the lands (2.193 and 2.196") and repeat 2.168" and do two more steps that way (2.165 and 2.162).
@JaSa - Yeah, I figure the velocity node is probably a bit below 45.5 given the trend. They are loaded with an RCBS Chargemaster, so +/-0.1grains is likely happening anyway.
@Moa Hunter - Yup, there is much I don't understand too. I think Litz is onto it when he says we read far too much into very small data-sets - statistically the the good groups above could be just random occurrences.

I’d say 2.165 is going to be about where you find your accuracy there.
Should pull it in nicely.