Probably many of you are not aware of this but you need to be aware. In the Republican Party, probably around 40% of the leadership would be in favor of drastic England-style gun control. Probably about another 15-20% don't really care that much, and the only reason they're not voting for these gun control laws is because they don't want to lose votes and support from their constituents. Only about 40-45% of the Republican Party leaders actually believe in gun rights, as a matter of personal opinion. Those who make up the Republican Party leadership are not as socially conservative, percentage-wise, as the body of Republican voters as a whole. A lot of gun rights defending Republicans in the U.S. are not aware of this situation. You have no idea how much of the Republican Party is composed of RINOS. Many of them are practically Democrats who just don't want higher taxes and want fewer regulations on large businesses. Do not think that just because Republicans hold a majority you are safe and there's nothing to worry about. Many of them could turn over to the other side on a law if the chance prevented itself. That is if there wasn't a big enough margin of support from within the Party to keep them in line, since the Party in practice exercises a huge amount of influence on how politicians vote on certain issues. If there is only 35-40% of the Republican leadership opposing a certain law, these RINOs will feel free to join the Democrats on voting in favor of the legislation. This was clearly demonstrated by the Gun Free School Zones Act in 1990. The situation is not as good as you think. Don't automatically assume that just because they're in the Republican Party they don't think the same way Democrats do on certain issues. Some of these Republicans have a very authoritarian mindset. Mostly this is Representatives in the House, Republican Congressmen who were elected in Democrat dominant states. Obviously Republican Senators only tend to get elected from Republican dominant states, where the attitudes are different. Now, on the Democratic Party side the situation is not quite as bad as you think. While the Democratic Party is obviously known to be in favor of pushing more gun control, probably about 35-40% of the Democratic Congressmen are not that keen on more gun control. Maybe about 15-20% of them could be pushed to vote in favor of more gun control, under pressure from the Party leadership, but there's a solid 15-20% who are going to hold out. Actually those who dominate the Party leadership in the Democratic Party are, percentage-wise, more socially to the Left than their actual members of Congress are who are Democrats. Don't underestimate their ability to sell out though. Those who are loyal to the Party and vote as part of a block are rewarded with all sorts of perks, Party support during elections (many members of Congress are incumbents, career politicians) and often lucrative job offers in Washington after they leave their political careers. So it's no wonder they usually tend to vote as a solid bloc on legislation along party lines.
