Chip Saunders
Have machinegun fun, without the federal hassles of machinegun registration,...legally.  
 For those of you relatively new to owning weaponry, you may or may not know about the status of owning a machinegun in the United States. Assuming you live in a state where it is not prohibited, federal statutes allow for citizens to own machineguns (and other cool military destructive things). But using the Congressional authority to levy taxes and the judicial power to ensure collection of tax, machineguns carry a $200 transfer tax, and purchasers must submit to authentication, fingerprinting and registration. Because the supply of newly manufactured machineguns was frozen in 1986, and the number available is fixed and finite, prices for all machineguns have been rising steadily since 1986, beating out nearly all other commodity investments. (Yes, including gold and silver.) For example, a select-fire M-16 - our nation's service rifle - that sold for only $1200 in 1985, now sells for $15,000 - $22,000. (Nothing like limited supply enforced by possible prison time for circumventing the rules to drive up prices.)
And yes, it has long been possible to those with the technical aptitude and capability to simply take a civilian-legal semi-automatic version of a machinegun design (such as an AK47, AR-15, Uzi or whatever) and convert it into a machinegun. But as mentioned above, the cops take a dim view of that, and while you would save thousands of dollars,...you might lose a few years to The Man.
In recent years, a specialized technique of trigger manipulation has been developed by some shooters that replicates machinegun fire. It is known as "bump firing". Essentially, the technique is to hold the gun somewhat loosely in a "static" manner, in the hopes that under recoil, the gun actually lurches back forward immediately after the trigger is pressed, causing the trigger to "bump" back into the trigger-finger, re-pressing the trigger and firing another round. It is difficult to master, and even those who have mastered it, are often unable to exercize a great deal of control or accuracy over the weapon, due to the loose hold. But because the trigger is actually being pulled or "bumped" for each and every round fired, it escapes the federal definition of a machinegun, and "bump firing" is legal to do.
Just today, I became aware of a product for one of the most common rifles in the U.S. which creates a stable condition for producing "bump fire", keeping everything legal (for now) yet making the experience and effect much more controllable and reliable. If you own an AR-15 rifle (and you should), this product will make you grin.
Just such a device was previously developed for the popular Ruger 10/22 rifle back in 2006, called The Akins Accelerator. It sold briskly for about 2 months, before the Bureau of Alcohol, Tobacco & Firearms decided that (despite meeting the letter of the law as a non-machinegun), it simply could not be afforded on American streets, and was outlawed with the stroke of a pen. Will the same fate befall this new device? DON'T WAIT TO FIND OUT!!
Currently, this product is not required to be registered, and you may order one without restriction.