The numbers I've heard put it closer to 80,000,000. And 30% of Democrats own guns, so they're not going to all be conservative, either.
I think the first step would be to back off the issues that both sides don't agree on - immigration, social policy, etc. when talking to other gun owners. Don't say "don't vote for candidate x, he is very anti-gun and a socialist to boot," just say "don't vote for candidate x because he is very anti-gun" and calmly explain why. If you bring anything else into the mix you run the risk of putting people off.