bump fire??

ok I've been kicking around an idea in my head (completly theoretical of course no patent infringment here)

http://www.ar15.com/forums/t_3_4/571714_Homemade_Bump_fire_stock.html

first KYDEX...the .098 stuff is tuff as nails and could be formed (with patience and vacuum forming(space bags)) around the existing pistol grip with a gap on the left side to install/remove. also with kydex you could form necessary bits to rest the finger on and to prevent getting bit under the trigger guard. aside from that, same as the ARFCOM...except

sig brace

obviously the M4 adapter and sbr it would be the easiest way to go, not to mention safest legally. considering NFA laws being tip toed around ALL OVER THE PLACE.
again guys I'm NOT doing this just had a thought! I'm in no way advising anyone to do this unless you desire to owe $250,000-500,000 and 10 years in fed prison

just looking for entertaining conversation

but I'm curious if it could done to the sig brace, the idea on an ar is cool for about 15mins then reality of cost comes in.
with the vector I'd like to think that cool factor would stick for a while!

I considered the same thing now that the M4 adapter is available. I just dont think you would get enough recoil going backwards to bump fire it. Most of the recoil is going downwards (as designed).

true but they work on 15-22s
I'm quite sure even the reduced recoil of .45 is more than a .22
yes, some 15-22s use a lighter trigger but it should be enough to do burst
which I think would be better than the headache/cost of a barrel "swap" after destroying it due to sustained rapid fire
finally one could do the home brewed trigger job if nesessary

back to the sig brace, I heard that some needed to add to the buffer tube to make it stay on...obvisously the nominal OD buffer tube would be needed to even consider making it work. I wonder what brand buffer tube were they using