I'm sure some here will argue the point, but in my legal opinion, if you have an AR15, having any of the M16 fire control components in your possession (not even installed) is quite risky and certainly enough for an aggressive prosecutor to get an indictment. You want to spend thousands and thousands of dollars to try and beat it? Certainly having enough M16 parts (whether installed or not) to cause the gun to fire more than one round per pull of the trigger when they are installed, even if its a fluke and not consistant, will be enough to put you away. That is, if BATF can install the part or parts in question and get your rifle to fire more than one round per pull of the trigger (even with a little tinkering), you are in deep kim chee.
So how many M16 fire control components can you have before you put yourself in legal jeopardy if you also have an AR15? In my legal opinion, none.
shaggy (esq.)