Regarding the calibre; The 16 gauge is proofed to > 32.000 PSI. So it should be able to take the 450 NE. But will the gun be to light?
Regards Nagell
Hi!
Have a 16 gauge merkel 8 so its probably the same as your simson. How did you find out the prooving pressure, sound quite high but if its right it would take more if the base of your cartridge is smaller than the 16 gauge.