Fired case neck dimension

[Doom]

I think there is only one normal neck chamber diameter for a no turn neck? Check a few SAAMI chamber blueprints. The manufacturer may not be legally held to that dimension. But my guess is they do.

For 6mm. I thought a no turn neck was always .272".

The SAAMI chamber neck diameter as shown is a minimum diameter. It may exceed that value typically 0.002" but in reality it may exceed that.

 

[MikeT49]

I had P T & G make me a reamer for my newest 6mm, a 24 PRC. Sent them dummy rounds to make a no turn reamer. The brass is necked down Lapua 6.5 PRC brass. The neck on the reamer is 0.2773. Neck OD of loaded brass is ~ .274.