Hi DesG ,

I'm firing at up to 100 yards with my Marlin using 7.2grains GM3, you have me a bit worried as myself and several other club members are all using GM3 powder with any thing from 6.5 to 7.5 grains

There does not seem to be any problems that can be seen but what rifle, distance are you using and what sort of accuracy are you getting please?