i got my new delta force catalog and saw this. can this really be legal?
www.deltaforce.com/catalog/uniquetriggersystems.html

Bump fire assist device.  Save your money.

yes it's legal but more importantly, it's garbage.  It is not a machinegun nor does it turn your rifle into one.  

i've seen similar types in the past and they are hard to setup and are very sensitive to abuse.  They don't work well.  

i'm glad i asked. thanks. maybe when i make my millions i can get a DIAS.

Legal?  Sure.  It's a trigger activator, just another in a long line of add-on gizmos that guickly toggle the trigger back and forth between the release and reset points.  Nothing new.  It still fires one shot for each trigger pull, so it's not a machine gun by definition.

However, these tend to be unreliable, very uncomfortable on your trigger finger and prevent you from firing it from the shoulder due to the way the trigger must be pulled.  They're usually for hip-firing.  You'll install it and if it works, you'll mumble "cool" to yourself, use it on a couple mags, then uninstall it forever.  That's usually the way these work.

And FYI, some states do prohibit these.

the most important thing to remember is you can learn to bump fire without one of these...