Here are the facts: Full automatic firearms are all subject to the National Firearms Act, meaning the purchaser must apply to the BATF for the transfer of the full automatic firearm from the owner, as well as pay a $200 tax. In other words, you do not just walk into a gun store and walk out with a full auto firearm upon passing the instant background check. And once the full auto firearm is transferred into your possession keeping it locked up is a given since there are relatively few of these firearms in circulation, the result of the NFA rules being changed in 1986 to prohibit the sale of full auto manufactured after 1986. Those that do go through all the hoops to acquire a legal full automatic firearm, like an M16, will pay in today's market about $20,000 for the firearm, while a semi-auto AR-15 can be purchased for about $1700 or less.