Re: Keeping E.S. under 20fps.
I have been keeping track of velocities and numbering rounds like you for a little while now, with the 300 Ultra anyway. I haven't seperated any out or sorted them but, I do note what number cases I'm shooting on the target with their MV. It's organized better than it sounds. [img]images/icons/wink.gif[/img]
I use the MTM 50rd boxes and each round gets put in the box in the same spot and stays in that hole. Looking at the open box, I number them 1-10, left to right, 11-20, 21-30, 31-40, 41-50... front row to back row, five rows in all. The next cartridge box is labled (51-100) and is 51-60, 61-70 and so on... I don't mark the cases themselves as it always comes off, I do however take great care to only remove them one at a time or keep them in order in the loading block when prepping and loading etc... I don't feed mine from the mag, but if I was going to then I'd mark them all real well.
Only thing I've really zeroed in on so far is one case out of the 100, #35, and it's been 20 fps faster and 3k psi higher on two occasions now, much farther than any of others which are holding about a 30 fps spread right with this load. I'm shooting it again tomarrow and will weigh it after if it shows up fast again. I still want to go back and look more at how consistant the others have been on seperate loadings. I definitely seen a spread of 10-15 fps with the same case when looking over ten to twenty that seemed higher or lower than the average MV.
Just reloaded some cases, #1-10, that I had done some MV and psi testing using Retumbo... all but two were "almost" too loose to hold primers now. That was only the second loading on these cases too! Pressure never went over 63k psi on the Oehler, but ejector marks and stiff extraction were still seriously evident. So, at this point I know I'm doing better MV wise with RL25 and it isn't thrashing my cases all to hell either, I have some at over 5 loadings so far and primer pockets are still tight, some of these loads were pushed "alot" higher than wih Retumbo too.
Looks like I'll have to do some testing to see what level I can get to with Retumbo and keep these cases alive for a while, doesn't appear that even 63k psi is going to work that well.