Why don't they make different calibers?
 

Just something that I always wondered about airsoft.

Everything uses the standard 6mm BB, for sake of compatability I guess. However, the purpose of Airsoft guns is to mmic real-life counterparts, right?

What I don't understand is, why different calibers of BB systems haven't been introduced. Like, for instance, a larger pellet for SAWs, or 4-5 mm pellets for SMG's and handguns.

The only reason for this I can think of is how tesselated the parts market would be.

Your thoughts?

There are 8mm guns.

pellet guns use 4.5mm
there are 8mm guns but the BBs are expensive

8mm sort of still exists as a parallel standard for some guns (mostly collector models now), but it was never really feasible for use as a skirmishing caliber because the bbs themselves are simply too massive to use on a person at that point.

6mm has become the dominant standard partially because of many companies saving massive amounts of money on R & D by directly copying Tokyo Marui design elements, and more recently because a 6mm bb carries optimal ballistic properties given the speeds and distances at which we shoot them.
4mm is too small to carry enough mass in polymer mediums to be effective, 8mm is dangerous once it's got up to speeds deemed effective in skirmishing.

Do you have any idea how incredibly irritating it would be to NEED 3 different calibers of ammo for every game??
And not being able to get certain guns in certain calibers?

And as said, the 8mm was just inherently SO heavy, that by the time you got it to an effective relative FPS to get great range and accuracy, it was in the 4J area, way above what's field legal anywhere.

If you spend 5 minutes to think about it , the reason should be clear