I bought a desert eagle pistol that came with 2 C02 mags. The gun shot amazing, long range and accurate, but it was shooting 435FPS. So, nope couldn't field it. Everywhere was 400 - 420. Had to buy some green gas mags. Now it shoots 385, still long range and accurate, but it's gameable. I never thought, "Oh its a pistol so it shouldn't count for FPS rules. Its a weapon system, just like rifles, shotguns and SMG's.
Nothing says loving, like a head shot!