I have been reloading GP11 brass and found RCBS berdan decapper working awesome. For the once fired GP11 brass, I just ran a few turns of a big drilling bit with my hand over the primer pocket and it was pretty easy to remove the crimp.
There was always hang fire using Russian Berdan primer from Canadaammo and I was lucky to find some RWS Berdan primer on CGN and it has been working flawlessly.
Target Shooting Products can bring in RWS Berdan primers, but needs quantity, anyone interested can give them a call for them to see the demand and maybe they are going to bring some into Canada.
I set my loading data for 7.5X55 at 51.2 grains of Reloader 17 and 175 grain 30 cal Berger OTM and produced decent accuracy, usually 10-shot group under 2" @ 300 meters shot from my Hammerli-Tanner rifle.
Several days ago, I saw a guy pushing 155 grain 308 bullets at 3150 fps, so I thought maybe I can push 175 grain Berger OTM over 3000 fps in my Hammerli-Tanner in 7.5X55, so I loaded 15 rounds with Reloader from 51.5 to 55.7 grain with 0.3 grain interval, with 55.7 grain to be just full of loaded case.
Shot it today without any pressure sign straight to 55.7 grain, with the muzzle velocity increasing from 2680 fps to 2971 fps (55.4 grain), but dropped to 2961 for the last round with 55.7 grain.