Hi all, I've been working with Stryker pistols for quite a while, and they will usually loose 400 to 500 fps in their 14 inch tube from a 24 inch rifle. You can cheat the system some, but you can't even up, so to speak. I get 3500 fps out of the 22-250 win 45 gr factory's in my stryker, and my father's 300 wsm stryker acts as though it is an '06 in a rifle.
These guns will flat shoot, and my longest kill with a pistol is 1/4 mile on a prarie dog. Short barrel= stiff.
You can work with slightly faster than normal powders AND magnum primers to lessen the loss, watch your pressures though, as the short barrel sometimes masks hard bolt lift. You don't get it until you are WAY hot.
The best I've done is 2800 fps with a 100 gr in a 243 with a 14 in barrel, about a 200-300 fps loss compared with a 22-24 in barrel. The load was a 100 hornady, Vit 540, and a Fed 215 mag primer. I haven't tried to push the 22-250 yet, it's fast enough already.