FX Royale 500 and H&N Grizzlies

Any Royale 500 (.25) owners out there who've tried H&N Grizzlies? Being on fixed income I try to prioritize on my airgun expenditures. Just curious how well these shoot out of the Royale. I'd be happy to trade a fistful of polymags, Hunter Extreme, JSB Heavies, MarkII or even some varmint knockers (fit VERY loosely in the mag & gun didn't like 'em). PM me if you want to swap or just post if you have personal experience with this combo. Thanks 
 
My Royale 500 shoots JSB Exact 25.39, MKII'S, Hunter Extreme, Barracuda & Polymags (in a single shot tray or with enough of the tip clipped off to fit in mag) VERY accurately. Was just curious about other's experience with Grizzlies but the negatives seem to outweigh the positives. Not so curious anymore. On the Polymags, I'm surprised at what little appreciable difference there is in accuracy when I clip the tips to fit them in rotary magazines. I hunt with them quite frequently. I'm just looking for as much energy transfer to my targets as I can get. I'll try some Crow magnum I guess & see how they work.