full auto kit help

i have a RRA m4 carbine and was wondering what all i needed to but for it besides the tax stamp to make it 3 round burst?

About $15K…

To use the 3 round burst you most have the auto sear pin hole.
You can Not drill a auto sear hole in your lower big NO.
You can buy a registered drop in auto sear they run $15k + Last time I checked.
You can NOT manufacture full auto will go to jail.

It has been unlawful to manufacture a transferable machine gun since May 19, 1986. To convert your RRA lower would be manufacturing a new transferable machine gun, which is now illegal. You could buy a lower, drop in auto sear or lightning link registered May 19, 1986 or prior, but supply and demand kicks in. The supply is finite and the demand great, hence the $7,500.00 to $17,000.00 you would spend depending on your taste.

There is an old adage that comes to mind, something about champagne taste on a beer budget.

And with that we are in lock down.