Wilson Case Gauge Design Error (I think)

[Hick]

I bought a Wilson case gauge for 32WS. It is supposed to check headspace tolerance and overall case length tolerance. Unfortunately, the 32WS case is a rimmed case and headspaces on the rim. Wilson thinks the headspace on 32WS is controlled by the shoulder (like a rimless case). So--- they made the cutout for the rim extra deep so the rim will not touch, and designed the gauge to check the rim tolerance at the shoulder (which is only a minimum dimension). This means, among other things, that if you only neck size, and your case shoulder is as-fired for your chamber, the case will not go all the way into the gauge and you cannot check for proper case length. It won't go in because your as-fired shoulder will hit the minimum shoulder in the gauge before the rim fully enters the case gauge.

In other words-- their case gauge will only work on a rimmed cartridge if you full length size very time.

I contacted them and told them I think it is designed wrong. They told me the gauge is designed to check "headspace to the shoulder" as required for all bottleneck cartridges. They don't seem to realize all bottleneck cartridges don't use the shoulder dimension for headspace. I don't think they have read the SAAMI specs, and if they are going to check headspace they have to check the right thing (not the shoulder).

Of course-- I could be wrong, and I'm sure somebody will let me know if I am.

[M-Tecs]

I set all bottleneck case headspace off the shoulder even if it's a rimmed or belted case. This includes cutting chambers. I have my rimmed and belted headspace gauges ground for the shoulder dimension. While not SAAMI it allows me to hold -.002" for shoulder clearance. While rim thickness and belt thickness does vary it doesn't change unless damaged.

http://www.lewilson.com/casegage.html

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 measuring a case in AS-FIRED condition. Take a measurement. Resize case on current die setting. Then place back in the gage to see just how much you are sizing the shoulder back. Finally, adjust sizing die accordingly. 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.



Personally I find the Wilson type gauges of limited use compared to the RCBS case mikes, MO's gauges or the Hornady Lock-N-Load Headspace Comparator.

When reloading I can not control nor change the rim or belt thickness. Nor have I ever seen a belted case or rimmed case that was over tolerance.

Other than checking for a damaged rim or belt what meaningful measurements would the Wilson gauge provide if it checked the rim thickness?

[Hick]

M-tecs--- thanks for the added info. Notice that your quote from Wilson says that the gauge is intended to measure as-fired cases-- but their customer support people are telling me they cannot measure as-fired cases in 32WS. In fact, they told me the gauge will only work with full-length sized cases. They are right about this-- my gauge will not accept an as-fired case. This is part of what makes me think their design is wrong, since it cannot do what they say it does.