With brand new brass, I chamber one to make sure they will fit my chamber - then I only true up the neck (running them ove rthe expander buttom of the die. Some ctg. necks sometimes gets a bit crushed or bent (not round) on one side or the other from banging against others.

They will already be FL sized. You should not have to do this.

I think you might have a long chamber and/or you are pushing the shoulders back when sizing. overly sized brass will appear to be producing excessive pressure.

1,100fps ????????????????????????????????????

You should inside and outside chamfer the case necks before loading - again, they should not need sizing before fitting a normal chamber.

Since factory ammo fits, new brass should as well.