As freakshow said, it's a gray area as to whether it violates federal law, so no, NOT without a doubt illegal as to federal law. But TC vs. US indicates that this is probably legal.
As to FL state law, I do not think that Quiet is correct at all when he says that the Defendant "clearly violated" state law. Let's look at the statute [which Quiet] posted again:
Quote:
Florida Statue 790.221
(1) It is unlawful for any person to own or to have in his or her care, custody, possession, or control any short-barreled rifle, short-barreled shotgun, or machine gun which is, or may readily be made, operable; but this section shall not apply to antique firearms.
(2) A person who violates this section commits a felony of the second degree, punishable as provided in s. 775.082, s. 775.083, or s. 775.084.
(3) Firearms in violation hereof which are lawfully owned and possessed under provisions of federal law are excepted.
In fact, paragraph #3 specifically states that "if it's legal as to Federal law, it's legal as to this FL state law" - so we're clearly and unambiguously BACK to Federal law (look at what freakshow10mm said above - back to the case law of T/C vs. US, which said that "there ain't no such thing" as constructive possession, at least in my understanding).
In addition, EVEN if paragraph #3 were not in there, as MisterMike points out, there's still no constructive possession in paragraph #1 - true, it's "operable or readily made to be operable"** - no question about that. But that's only one of two requirements. It's also must be either an SBR or SBS or machinegun, to be illegal. So we're back to the definition of "what is an SBR?" which doesn't *necessarily* include this so-called "constructive possession".
**Note that it doesn't say "readily made to be assembled into an SBR", or "readily assemblable into an SBR" or anything else similar to that - 'operable' in this statute means merely the gun fires or can be made to fire - utterly nothing to do with barrel length. And it's an "AND" connector between operable and one of the three no-nos (SBR, SBS, machinegun) before illegality kicks in.
So no, it's not clear at ALL to me yet that he committed any crime, either federal or state.