I am getting one of the 12" havoc launchers. Where does one find 37mm CS/OC type rounds?  Everything I have read these are okay without going DD route (which I will eventually do) as I want a 22lr beehive and want to be able to legally shoot and play with some other stuff.

Just wondering in the interim where I can get the other stuff aside from smoke, flares and fireworks.

Your best bet is to make what you want. Just becareful to stay away from anything that might be an anti personal round.

Make all my own rounds and it is 1/2 the fun

www.ammunitiontogo.com has 37mm rounds (alittle expensive)

and

www.AmericanSpecialtyAmmo.com has alot of reloading supplies and smoke rounds (much better prices)

Check out Grog's Site for reloading information (buy his CD).

As far as manufactured CS or CN rounds, pretty much the surplus market is where your going to get them.  While they never really came out and said it, ALS probably stopped selling those to the Civilian market when the ATF nudged them to stop selling smoke grenades.  Only reason I think that is the above websites really stopped selling them.  In the past, they were plentiful on the market new.  But nonetheless, if you want one, you can usually find them on Gunbroker.com

Good luck

Check out www.reloadableshells.com too