Case Gauge vs. Barrel for Ammo Check

[Phyffe]

Wobbly,

What's your opinion on using a case gauge as opposed to plunking?

I've found that comparing my Shooter's Box case gauge to my pickiest barrel (P10-S), some of the rounds that fail the case gauge would still plunk in the P10-S. That's what I take with me to the store when I buy ammo new to me.

[Wobbly]

This topic is going to split this off into a new conversation that stands on its own.

1) Even though related, it's too important to bury on the 3rd page of another conversation. I think this has application for a much wider audience.
2) It's important enough to warrant input from more members. (I post a lot, but that doesn't make my opinion correct on every occasion or topic.)

Regards

[Wobbly]

If you know that your gauge is "more picky" than your tightest barrel, then I can see the motivation for taking the gauge with you when buying ammo locally. Speaking as one who has pulled out a barrel in a gun store and gotten those VERY strange looks from the guy across the counter, I can understand.

[And I will tell you that I do not buy a lot of case or cartridge gauges. I'm still using a nice, steel, single-hole gauge from Midway purchased about 1990 ! I keep it lubed with sizing wax that so far has kept all the corrosion away. ]

What a gauge will tell you is about the physical dimensions of the case.... the decreasing diameters along the tapered case body and the concentricity. It will also find distortions along the rim due to rough handling by the extractor. It will tell you if the bullet is seated co-axial with the case, and it may tell you if your cartridge is too long to fit the mag. (That is to say, if it exceeds the SAAMI max length of 1.169".) But, the gauge does not tell you anything about the freebore and the bullet clearance to the rifling.

For that one single measurement, you need the barrel. Only the CZ barrel has the rifling in position to tell you about the OAL. So I would take the barrel with you and do the "Plunk & Spin". If this is a pain, then take it once and try every cartridge type/ style/ brand in the store... and record the PN's of the ones that will work on a note pad or with your camera. That way you have the manufacturer's PN and can build a data base of ammo that works for YOU.

Once you know what brands are OK, you can buy without any gauging. And, if you're reloading and doing the Push Test, then you can use your gauge with confidence, knowing that the OAL is good to go.


Newer gauges may give the user more information. I admit, I'm old and my old processes are built around my old tool set. What do you see ?

[Cinimod]

When I was shooting USPSA or PCC I reloaded all my rounds. I was using once shot brass which I cleaned, decamped and resized. After reloading all my rounds I used a case gauge on all the reloads and checked for high primers. I’d case gauge to insure the round would chamber and if there was a high primer the primer wouldn’t ignite and the round wouldn’t fire. I never case gauged factory ammo. If you have to case gauge factory rounds then there’s something not right.

[Wobbly]

I never case gauged factory ammo. If you have to case gauge factory rounds then there’s something not right.

Welcome.

1. You didn't say what brand/type/model gun you were shooting back then. And if it was a CZ, whether the chamber had been reamed. I'm sure what you did was fine for you, but in this conversation we are including everyone, up to and including rank novices with a brand new, stock CZ that are buying assorted brands of ammo each week for a Saturday outing to the local range.

2. If you are reloading then you may be unaware of the recently reported issues with factory SIG and Fiocchi ammo. Or, maybe if you do buy factory ammo, you tend to purchase Federal or CCI and have not seen this.

[Cinimod]

I should have said I only reload because I shoot a custom 9 major open gun with a fully supported match chamber. You won’t find this ammo in your store. For a carry gun only use factory ammo that’s for legal purposes only.

[tdogg]

I agree with the statements made above.  If I was competing with factory ammo I would be checking it with a gauge too just to be sure it chambers.  Case gauges don't confirm the OAL/bullet fit in your barrel chamber as already indicated.  What the case gauge does do is perform a quality check to ensure there aren't any out of spec cartridges in the batch.  The mfg doesn't perform QC on everything they make, by gauging them all you ensure they all will chamber in your gun properly.

I also use the gauge to ensure the primers are seated properly.  I use a Hundo 100 rd gauge so it is easy to see and compare them side by side.  I run my finger across them and feel that there aren't any sitting proud.  I also look at them to ensure they all look normal and not crushed/deformed/damaged etc...

One other thing I like the Hundo case gauge for is to mark the case head with a sharpie.  It makes it easy to mark all the cases for ease of identifying.  I do this for picking up my brass at local matches and to identify anything that doesn't run at majors.

The final thing about the Hundo case gauge is that it lines up perfectly with the MTM ammo boxes so you can easily gauge and then load into the boxes with a flip tray.  It's a first world problem but nice to save a little time loading the boxes.

Cheers,
Toby