Y is nearly zero. Those who are anti gun will always be able to say whatever Bush does it was "too little", while X is a very large number.
The NRA bloc voted in 1994--mostly by accident.
And then they stayed home to varying degrees in 1996, 1998, and 2000. The early results say that they barely showed up in their 1988 numbers in 2002.
If the NRA bloc refuses to vote, and to generate a LOT of votes, then politicians will naturally ask "What have you done for me lately?"
The "NRA" voters as you call them (you don't really have a clue though, the NRA is considered by many to be a bit too anxious to compromise our rights away salami fashion, although they seem to be improving a bit of late) didn't vote "by accident" in 94, they were energised by the passage of the very bill we are discussing the so called "assault weapons" ban.
I thought it was politicians who were supposed to do things for the people, not the other way around. Silly me, and silly them if they make that attitude very obvious.