By Al Voth -
I’m expecting the brown truck to drop off a new .22-250 predator rifle soon, so I figured it was appropriate to prepare some brass for handloading. Things were going just fine until I checked the case necks for run-out. The results were the worst I’ve ever encountered and presented a serious problem if I wanted that new rifle to perform to its potential.
Of course, straight ammo shoots better than crooked ammo, and anytime you can load cartridges with minimal run-out, it increases the odds of topnotch accuracy. I use an RCBS Case Master Gauging Tool to measure this run-out, and by spinning the cartridge on the gauge it tells me if the case necks are straight in relation to the body. In this case, I was consistently getting 0.015 inch of run-out on my freshly sized case necks. Considering that number should be less than 0.005 inch, I had way too much.
To get this number down, I tried a few tricks I’ve learned along the way, but nothing worked. Finally, in desperation, I borrowed a set of dies from a friend and sized a few cases with those. Neck run-out came down to a respectable 0.004 inch. And when I re-sized the cases I’d done previously, that 15 thou’ run-out straightened out to 4 thou’. That clinched it, apparently those .22-250 dies I’d purchased at a gun show were crap; they were turning straight cases into crooked ones. I salvaged some parts from them and the remainder made a loud thunk as they hit the bottom of my gun room’s garbage can.
The next time I walked into my local Cabela’s, a new set of RCBS .22-250 dies were the first items in my shopping cart. After setting up the dies, I sized three cases and checked for run-out again. Success! Each case showed about 0.001 inch total run-out. I sized a new batch of 50 cases and the last one was as straight as the first. These improved results happened with only a switch of dies; absolutely everything else remained the same. It showed me again that concentricity tools are well worth their cost; this time, by exposing a set of defective dies and confirming that a new set was precisely machined. If you’re not using one of these tools, it’s impossible to tell if you’re producing straight ammo, and your handloads aren’t as good as they could be.