BudsGunShop.com - Shell and Magazine

David, the magazine can be manually switched between tubes at will. Mini shells will not run reliably due to reduced charge not being able to reliable cycle the action. Cheers and stay safe!

Yes the magazine tube can rotate any time regardless of loaded status, so this way you can mix it up (buckshot in one tube, slugs in the others) and can quickly switch between with missing a beat.
Mini shells don't typically run well in semi-automatic shotguns unless you have an adapter, and to my knowledge there is not an adapter available for this shotgun.

NO, the IWI Tavor TS12 shotgun doesn't cycle mini shells. Yes, you can rotate to change the magazine tube even with the shell still inside. I hope this helps!