A great deal can be said about stretch gauge mounting but one does not want to state stuff that already are common knowledge for the potential user. Apart from the Contender's outside chamber profile which I have not studied up close I assume that the OP understands that using this mode of measurement is not a good way to build up a load to nominated pressure levels that had been published by the piezzo-electric way of measurement.
And furthermore, particularly to not use it to achieve maximum pressures measured by SAAMI or CIP. Please do not go towards maximum pressure levels indicated by Quickload - as for all its expense QL uses simplistic formulae that had been developed for particularly the 30-06 and .308W cases and have up to a 16% negative calculation error for any cartridge showing any amount of overbore. -16% means that you will get a 16% overpressure by building towards the QL figure given as maximum.
Building a user-defined database of own pressure traces and safe maximum values based on known velocities is the clever way to go. Can one ever overstate the following?: "There is not one iota of value in attempting to wring the last 50 ft/sec from a cartridge bullet combination". Why would one want his expensive, nice rifle to be working at maximum rpm every time he turns on the ignition?
