That's a great price on Stingers, but even at that the cost of running a thousand rounds through the Razorback is prohibitive.
I'm also looking at limiting my use of hypervelocity ammo to preserve durability though a properly modified GSG SHOULD be able to handle a whole lot of Stingers before any problems crop up.
Bear in mind that Stingers have a thicker case in the web and rim section which means they demand a hard firing pin strike....IF you have any issues with misfires, don't blame the ammo, pull the bolt and check the firing pin nose width. A bit of stoning reduced the width of my firing pin's nose by half and suddenly misfires of ANY ammo magically went away. I ordered a spare firing pin to keep on hand and discovered it was the same width as my factory pin AFTER I had stoned the factory pin down....clearly GSG is fine-tuning their product as they go and that's a good thing.