What would be a standard deviation in FPS on loads while using a Chrony? I am weighing each charge on a nice RCBS scale. Just curious as to what I should expect. Also factory chamber and no neck turning.

Depends wildly. If you fire form and only neck size, this will help considerably, but for small cartridges like your 204, you can get std devs low as 10fps. I have gotten as high as 100fps on my 300RUM or 338 winmag. Seems more powder, higher spreads. And you probably know, std deve is basically theaverage of the means. Or root mean square of the deviation from the means.

Thanks BC. Sometimes I hit 10 and most of the time it is 20 to 30 average, with a few fifties in there. Was just curious as to what would be the norm or good. So sounds like I should be ok and happy with the 20 to 30 then?

Alot of it has to do with the Chrono. My F1 Chrony isn't the best. I have shot over others and have gotten 20fps with my 300winmag.

Pistol cartridges however should be low as 4-6fps. Some.