yes it will fit your bushmaster but it will not make it shoot full auto unless you have all the required parts to make your weapon full auto not just the trigger.
No it will not. You would still need a m16 lower with the proper pocket and auto sear. I.e. preban 86 registered m16 lower or be a SOT and make post samples. Or have a registered DIAS.
I dont know for sure on the bushmaster but I would say yes it should fit. I have the AR 15 & the AR 10. the triggers are identical. As to whether it will function as a full auto the answer is no. It would also need the full auto bolt carrier group.
If you're bushmaster is mil spec it will fit. No it will not make your AR-15 full auto. The M16 has a different paddle sear and selector switch. The notch on the hammer is to interact with the auto sear. I would only recommend buying this if you have your build FFL or if you can find a pre-ban drop In. Otherwise stear clear full auto conversion is highly illegal. That being said this trigger is completely legal and will work like any other CNC trigger system as long as no additional modifications are made.