Can I Buy A Machine Gun At A Gun Shop or Gun Show?
Yes, no, or maybe? The answer; actually, is all three (3): “yes,” “no,” and/or “maybe.”
The broad answer is “yes” if is a pre-May, 1986. All machine guns made after this time are illegal for individuals to purchase, own or possess.
However, there are always exceptions. The very same machine gun may be illegal to purchase and possess if it is illegal to do so under state or local law. Most states have a law prohibiting machine guns.
Several states provide exceptions for those registered under the National Firearms Act. Without such as state exception, it is illegal to purchase a pre-1986 machine gun.
So what is the maybe? If the machine gun is a pre-1986, and not prohibited for sale and possession under local, state or federal law, it is not possible to buy it from a FFL(SOT) and walk away with it after a NICS check.
The reason, every machine gun must be transferred by completion of a Federal Form, usually Form 4. For individuals, this must be accompanied by fingerprints, photo, approval (signature) of the chief law enforcement, and $200 tax payment. The dealer cannot transfer this firearm to the purchaser (transferee) until the form has been approved and sent back by the ATF.
Failure to follow the strict provisions of the NFA and misdelivery of a machine gun is a felony and subject to substantial criminal fines. In addition, even if criminal charges are not brought by the US Attorney; the machine gun will be subject to seizure and forfeiture.
This itself is a significant problem with machine guns routinely costing $10,000 to $20,000 in average condition. High-grade machine guns in collector conditions (like new) may fetch tens of thousands of dollars. Strict compliance is not expected by ATF, but required.