Thanks Andy, just when I thought I had it sussed

I've prepped a load of brass in exactly the same way from 4 different manuf.

I tried them as empty cases in my action and found the bolt really hard to close on the S&B and Winchester. I've binned them, I'm not going to mess about.

The RWS and Federal cycled nicely and I have about 100 cases anyway which should last a while.

Weird!