Is the A2 birdcage classified as a grenade launcher in CA?  If so can you put a grenade launcher on a post-ban weapon in CA?  I’m thinking that there is a problem with that, however I did not find any part of our DWC laws that said that a flash suppressor or muzzle device is considered a Destructive Device.  

Do 37mm flair launchers count as Destructive Devices in CA?
- Sulaco

The A2 style is both a flash suppressor and a grenade launcher in the eyes of the ATF.  It is not by itself considered a destructive device, however.

Cool, thanks for clearing that up guys,
I knew it was a grenade launcher but wanted to find out if it was legal to have on my FAB10 in the PRK.  I should have the gun together by next week or so, so at least I don’t need to buy a new flash hider.  

Well if I can’t have magazines then I guess I’ll have to settle with having the telescoping stock, bayonet lug, flash suppressor and grenade launcher [;)]

At least for 10 rounds at a time it will feel like a real preban [:D]

I’ll have pictures n stuff after I get it together and take it to the range.
- Sulaco

You can modify the A2 bird cage by drilling out the inside and brazing a sleeve plus brazing an outer ring to extend the outside diameter slightly. You will need a lathe and the ability to repark for this. I've seen it done.