 In case a firearm passes such a proof-test a pass mark termed superior proof mark is stamped in every successfully tested firearm.Under SAAMI proof test procedures, for bottlenecked cases the centre of the transducer is located .175" behind the shoulder of the case for large diameter (.250") transducers and .150" for small diameter (.194") transducers.For straight cases the centre of the transducer is located one-half of the transducer diameter plus .005" behind the base of the seated bullet.