Nope... our offical Homeland Defense Rifle is the M-16A2.
"Homeland Defense Rifle" is basically a term thought up by gun owners for a affordable, light, hi-capacity, and adequately accurate and durable rifle that could be employed in case of terrorist activity or societal collapse.
The SU-16 fits this role almost perfectly.
It'd be NICE, though, if the Government were to issue one to every member of the official Militia... all capable male adults that are US citizens, that is.
If Theodore Roosevelt were still with us it'd probably come to pass...
Nowadays don't EVEN bother holding your breath even at the thought of such a thing.
In many ways I like the Swiss system of universal military service that lasts until you are old and gray.
I have been seeing pictures of the various proposals for the next generation of US military rifles. They look rather like something out of Buck Rodgers. But if these are adopted what will the military do with all those M-16s? I would think there would be an opportunity there to beef up Homeland Security, but I am sure the anti-gun crowd would mess up any proposals to "share the wealth." I guess all the M-16s will be given to the countries that recieve foreign aid.
I ALSO wouldn't expect the M-16 to be replaced anytime soon.
Most of the "experimental" new rifle/caliber combinations are just that... experimental.
The truth is, the military NEVER stops experimenting with the "Next Generation" of rifles... and tends to do nothing about it at all. You don't generally replace something that works... and the M-16 works very well.
At issue more than the rifle itself is the cartridge. There's a proposed new one in the works that is of slightly larger caliber and heavier weight... in an effort to correct the perceived lack of stopping power experienced shooting the M-4 short-barreled version of the M-16.
The 5.56 needs the 20-inch barrel to achieve it's "Mach 3" effect stopping power.... something the 14 inch barrel of the M-4 gives up. The new cartridge is designed with this purpose in mind....
The problem is, any new cartridge we'd adopt would have to be adopted by Nato, or at least approved by Nato for issue to any member country. This is an enormous task... the U.S. introduced the .308 as the 7.62 Nato, and just as member countries were finishing refitting with the .308, i.e., the HK G3, FN-FAL, etc., America made the largely unnanounced switch to 5.56mm right in the middle of the Viet Nam conflict, causing widespread consternation in the organization. Just as they were getting up to date with the .308, NOW they had to switch to the 5.56!
One example of an advanced service rifle that encountered problems of this sort is the Heckler & Koch G-11, a truly revolutionary caseless cartridge rifle. This rifle had completely passed all tests required for issue, and was in the process of being introduced to the Nato community and adoption by West German forces... when the Cold War suddenly came to an end and the East and West German forces re-united. The G-11 program was then scrapped.
If the US were to genuinely wish to go to a new rifle/cartridge, it would take at least ten years to fully implement it's deployment.