Obama The President - no - but - Shurmer and company - yes.
I can't recall the website that lists all the proposed legislation - maybe someone here can...
If you go there and search for bills that have the word "ammunition", there's quite a few where the bill's sponsor is proposing a rediculosly high tax on ammunition.
Ah here it is:
http://thomas.loc.gov/home/thomas.php
I looked for something current and there isn't anything I could find right now.
In the past though, Shumer and company had sponsored such bills.
They go no where.
More than likely that's what it is and not the president
(although I doubt
Obama the President would veto such a bill if hit his desk.)