My wife loves to shoot. I've owned guns during our whole relationship but she hasnt gotten into them until this last year when I bought her the Glock she wanted. My only qualm about having a SO that shares the same passion you do is that its hard to go off an enjoy it buy yourself sometimes. Its great if you can find a partner who likes to share in your hobbies but when you're together day in/day out, its nice to be able to get away and not have them be sad/upset that you didnt let them come to the range with you.
I also ride motorcycles (another big red flag, even more so than guns I found) and when I would date someone and think things could get serious I made it VERY CLEAR that there were two things in my life I was not getting rid of, my guns and my motorcycles (unless I decided proactively to do so). If they couldn't accept that then I couldnt move forward with them. Its a bit harsh but once that's clear and you've communicated this, its a much smoother road (and easier conversation when IF they try to bring it back up later).