So why hasn't McCain signed on?

Looking at S. 2577, Lautenberg's latest attempt to close the mythical "gun show loophole," I notice that John McCain isn't one of the eleven co-sponsors (up from ten the last time I talked about it--Barbara Mikulski (D-MD)has signed on).

The question is, why not? Sure--I realize that passing feel-good laws that do nothing to prevent violent crime, and instead serve only to infringe upon that which shall not be infringed, isn't exactly in line with what one might normally expect from a "true conservative," but it is consistent with McCain's history.

"Despite the tragic lessons we have learned, it is still far too easy for a convicted felon to buy firearms at a gun show. That is wrong," said Senator McCain in a recent press release. "This is not about what's conservative and what's liberal, what's Republican and what's Democrat. It's about what's right and what's wrong. And quite simply, closing this loophole is the right thing to do."

Here's some more history.

S.890
Gun Show Loophole Closing and Gun Law Enforcement Act of 2001 (Introduced in Senate)

May 15, 2001

Mr. MCCAIN (for himself, Mr. LIEBERMAN, Mr. SCHUMER, Mr. DEWINE, and Mr. CARPER) introduced the following bill; which was read twice and referred to the Committee on the Judiciary

Of course, I realize that his support for Colorado's "gun show loophole" closure bill was back in 2000, and his introduction of S. 890 was in 2001, and that much can change in seven or eight years. So let's fast forward a bit.

Is the "John McCain for President 2008" website recent enough? Looking at the "Protecting Second Amendment Rights" page, we find this:

Background Checks at Gun Shows

At a time when some were trying to shut down gun shows in the name of fighting crime, John McCain tried to preserve gun shows by standardizing sales procedures. Federal law requires licensed firearm sellers at gun shows to do an instant criminal background check on purchasers while private firearm sellers at gun shows do not have to conduct such a check. John McCain introduced legislation that would require an instant criminal background check for all sales at gun shows and believes that such checks must be conducted quickly to ensure that unnecessary delays do not effectively block transactions.

Doesn't sound exactly like a renouncement of his old "gun show loophole" closing ways, does it?

So I ask again, why not sign on as a co-sponsor of S. 2577, Senator? Or is my timing wrong? Perhaps you want to officially lock down the nomination, before lurching after the voters who are considering Obillary?