The party platform states the goals and objectives of the party, if you do not support those goals why would you stay in that party ?
Besides, the biggest issue in this election is not guns, "It's the economy stupid".
It was the democrats spending, and meddling that crashed the economy because they cling to failed Euro-socialist policies.
Unless a Republican President has a free hand he will not be able to undo their stupidity.
" the platform can't vote in November."
That statement right there shows you don't get it, the platform doesn't have to vote in Nov, it votes when campaign money is handed out.