Interesting. Here is a link to a website that provides the full text of the proposed bill:
H.R. 226: Plan is “to reduce the number of privately owned weapons” « American Everyman)
I guess that the bill is patterned on the 'buy back' programs that various cities have held in the past years.
Note that a person may only claim the credit (of up to $2,000, split between two years) for one gun (with a list of the weapons that can be turned in for the credit).
I doubt that it will pass. That said, it does not strike me as any attempt to confiscate weapons from unwilling Americans. One of my sisters has a rifle that was owned by her deceased husband; she has no use for it, and is always worried that her house may be broken into some day, with the rifle being one of the items stolen. Should this bill ever pass, I would hope she would submit the gun and get the credit (again, if it is one of the listed guns).