How to measure the case length

I am trying to establish how to measure the case length of a 20Bore to determine what length of ammo it needs. Please help.

Case length is measured by measuring the length of a fired case.

In SA it doesn't matter anyway as the only 20Ga ammo you get (if & when you get it) is 2,75".

Hey Obasch, the story with the weapon is that it belongs to my neighbours Gran's estate. He is trying to establish the case length that the 20Br will require. He has been told that 70mm ammo is available infrequently and thus he needs to establish what the specific case length that shotgun needs. If it is a 67.5 or 65 mm then the weapon is not worth relicencing.

Thus trying to establish how to measure the case length required when measuring the dimensions of the chamber. He is also not interested in using the wrong case length, which I agree with.

Thank you
Ryan

What is the gun's make?

Slipped my mind, I will get back to you but I dont think its anything but a working gun.

Dude, I'll take it.

Rosenthals in CT have 65 /67 mm cases, they will work in a 70mm chamber.
The reverse however is not a good Idea


So Listen to the advice of others, and gift the gun to me.

PS remove the fore-end, you should see the choke size and chamber lenth