swiftlucat

I'm trying to get Flan's mod content to work in my 1.7.10 modpack (modern weapons, ye olde, and simple parts to be exact). Every time i try to add the desired content, it either defaults me back to vanilla or doesn't register at all. I have tried installing it so many different ways it has given me a massive headache. can anyone help explain how this particular set of mods actually works here?