RCBS CASE MASTER GAUGING TOOL

Even if you're just curious with how consistent your press and dies are performing, investing in a tool to measure your brass is a good investment.

If you're a tinkerer, and like knowing everything about your brass, it's a must.

I have a bushing neck sizing die, and I use this tool to measure the case neck thickness of brass to determine what bushing size I should use. This is actually a pretty handy feature that is more reliable that trying to measure with your standard vernier micrometer.

I also use this to measure how concentric my rounds are, both with the re-sizing of the brass itself and of the seated bullets. This can also be used on off-the-shelf ammo to help sort out the rounds that might be fliers.

Lastly, this tool has an attachment you can use to help feel and measure for incipient case head separation. I personally use this a lot since I reload for .303 British, which headspaces off of the rim of the cartridge and is notorious for chamber dimensions. I often have case head separations before I have split necks or loose primer pockets. Usually I have to pay attention for that light ring that appears to form near the case head, but that isn't always a good indicator. With the little hook attachment, you can "feel" the inside of the case for the thinning of the case head, and, if you want, you can move the micrometer dial to measure how bad the damage is. It's a nice feature.