Case checker

Cartridge gauges don't check oal.
You need to check your rounds by dropping them into your barrel(s)making sure they chamber all the way. The 'plunk test '.
You should be able to twist the round when it's chambered. If you can't twist it, the bullet is likely resting on the rifling, and is too long in oal.

In 9mm I make up dummy rounds (no primer, no powder) and make sure they plunk & twist and that they feed by hand cycling them through the gun(s).
Search for the 'plunk test'.

Did you buy a case checker, or ammo checker?

Case checkers are for checking the case during the reloading process. Ammo checkers check loaded cartridges to determine they meet minimum SAAMI specs.

My understanding is that what you bought will tell you if the brass will chamber in your pistol. Either before or after you load it. The length of your bullet to the lands or what fits your magazine will not be determined by it. That also can cause a round to not chamber completly. That is done with the plunk test.

Captain Quack said:

This is what I bought.

https://www.amazon.com/gp/product/B00JR6EUT0/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

I saw it in a couple of videos talking about showing OAL and that just didn't make any sense to me so I thought I would ask.

Captain Quack.

Click to expand...

It does, however it fails to mention what bullet(s), then again how could it. What it does is check for SAAMI chamber min specs, likely for 115gr. If you are now using SAAMI OAL it will do that job.
Throats however are not all created completely equal, along with bullet ogive. As mentioned the plunk test will tell you better than a bunch of words here can, it is done with a loaded round to determine if the bullet rests on the lands.

https://www.egwguns.com/case-gauge-ammo-checker-9-mm-7-hole

What your gauge will check is...

• Cartridge concentricity
• Bullet-to-case alignment
• Case length
• Taper crimp (average TC, not your barrel's exact requirement)
• Case head diameter
• Rim condition
• Bullet not seated too deeply
• Maximum OAL for the cartridge to fit the magazine (In your case 1.169")

It cannot check OAL required for your barrel because it has no rifling.

Hope this helps.