Wilson makes a chamber gauge (gage is how they spell it) as well as a case gauge for .223. Chamber gage checks your loaded round and the case guage looks at a fired case for trimming and cartridge headspace. If unsure what you want, call them. I
think you might want the chamber gage. "Case guage" is sometimes tossed about loosely by us guys.
Pivot makes a point in that, if headspace is something you're concerned with, then a headspace set (Hornady) and a caliper might work a bit easier. However, the chamber gage is a great, quick check to use during reloading. I have and use both a headspace set and a chamber gage.
From LE Wilson's site"
Chamber gage:
Reasons to use the Min Dimension Gage
1) You want your reloaded rounds to chamber in a variety of guns
2) You want to check for uniformity of your rounds against SAAMI specifications
3) You want to pinpoint issues with your reloaded ammunition
4) You want a quick check to see if you are under MAX SAAMI COAL
5) You want to check factory ammunition you have purchased
We recommend using the Regular Case Gage for bottle necked cartridges to assist you determining how much to trim and push back your shoulder to suit your chambers headspace. Available in Select Calibers
Case Gage:
One piece gage that will check overall length to indicate the need for trimming, datum to head length to assure correct headspace and to prevent over sizing. Available for most popular rimless cases. The Cartridge Case Gage was designed with safety in mind and was invented by our founder Sam (L.E.) Wilson in 1935 after a fellow shooter approached him for help in solving a case-separation issue. The gage allows you to see just how much you are sizing back your shoulder on your cases.
This is best done by following the steps below.
- Measure a case in AS-FIRED condition. Note headspace measurement
- Resize case on current die setting
- Then place back in the gage to see just how much you are sizing the shoulder back. This can be measured by using the Case Gage Depth Micrometer
- Finally, adjust sizing die accordingly to desired shoulder set back.
After sizing your cases, there is a good chance the brass will lengthen. The gage will also check min/max case length and will point out the need for case trimming. This is an essential tool for every reloader.
Note: Does not measure body diameters. This gage is intended to be used with fired cases to determine a basis for full length sizing and trimming.
Dillion is good as is Hornady. The gauges are cheap insurance especially if you're picking up range brass. They do not max overall bullet length, so don't throw away your calipher.