What are all the available airgun calibers?

Plus these big bores...

.308
.408
.452/.457
.58
.72


Tedd

As far as commercially available, I think you hit all but the .45. Then there's the home made airguns which could be any caliber the creator decides. I've held an .80 cal. in my hand. What a monster that was! 
Tom

I have a 400 caliber (yep 4") ....... wait a minute you said air guns so never mind!
That does give me a thought though. I'll get back to you as soon as it is converted to 
unheated air!

Thurmond

303 also

There's also ,257 and .375 and .400. Not sure if it's the same as .408 or not.

Isn't 20 cal fading fast?

.17
.20
.22
.223 john bowman rifle
.25
.257
.258 7mm
.30
.303
.308
.338 john bowman rifle
.356 9mm
.357
.375
.40
.452
.457
.458
.495
.50
.52
.54
.72
Pretty sure ive covered all the calibers i can remember off the top of my head, hope this helps.
Dan.C
Vermont airgunner