Sorting By Rim Thickness

  • Maybe this has been discussed already I would like to share my findings. I noticed when chambering rounds in my RimX some made the bolt a little harder to close and being the curious monkey that I am and I didn't have anything better to do I started measuring rims on this particular brand of ammo. I measured one box of fifty and came up with the min max numbers. Anything from .041 and above went in one tray and the remainder were labeled .040-. Thick vs thin. The average thickness variance in aggregate was around .002 on the minus side plus or minus tenths. I probably did this wrong so anyway I carried on and sorted two bricks. There was quite a few that measured dead on .041 the remainder slightly thicker. The thin ones had more variance and there was more thin than thick two boxes of fifty to be exact. So, after all this I put them to the test on paper. The thicker ones did perform a bit better and you have to remember I have a tuner on this barrel. The thinner ones shot slightly larger groups but not every time lets say they were less consistent. Here comes the control test. I loaded up with the same lot number of unsorted out of a new brick and shot the same amount of five shot groups the same day with everything warmed up and same conditions. These groups were more consistent than any of the ones shot with sorted ammo. After all this I now have two bricks of ammo that shoot slightly different. Maybe the tuner would straighten them out maybe not. Trying to make cheap practice ammo shoot by sorting it is futile. Like trying to make a silk purse out of a sows ear.

  • This is generally the result of sorting. The reason is that during handling of the ammo you sort, the lube uniformity is harmed in some way. It’s very hard to sort without touching the bullets.

    You are correct in that sorting cheap ammo doesn’t often produce worthwhile results. My solution was to simply purchase higher quality ammo that doesn’t need to be sorted to perform well. ;)

  • @orkan Exactly what happens when you insert the round into the gauge it disturbs the lubricant. I have the Hornady model and at the mouth of the cylinder where you insert the round the lubricant builds up because it's a pretty close fit. Plus all the handling involved during this. I can load my RimX magazines without touching the projectile if I am careful.