Well, you're also not taking into account that a 4.5mm bb weighs almost 3 times that of an 6mm airsoft bb, so saying "my gun doesn't shoot above velocity limits" is shennanigans. A typical .177 bb weighs about 8.5 grains, or roughly .55 grams. 300 fps @ .55 grams = 2.3 joules of muzzle energy. A .2 g 6mm bb travelling 500 fps has a muzzle energy of 2.32 joules, for reference.
That's far more than most people are willing to play with. Granted, your 4.5mm plastic bb is going to be much lighter, but then it will also have a higher muzzle velocity.
Suffice it to say, I doubt any reasonable game host would allow it. I wouldn't want to play against that....
...unless you let me shoot back with a primer-powered 6mm Remington firing bb's from crimped cases....then you're on.
Last edited by Skruface; June 2nd, 2008 at 00:50..