i

Is seriously so easy to rank up guns. All you have to do is go to the portal website and create your own experience. Make it breakthrough on the best map where is infantry only. Or you can do domination or tdm against bots only. I did this with conquest to practice flying and rank up all my vehicle vehicles. Within just a few hours, I had most of the best weapon unlocked for all the vehicles. You get full progression and bots are easier to kill.

If you want to just get a few attachments, just go in with every class and swap around the guns. You’ll have the most basic attachments unlocked quickly for any gun that you got available within one match. Also, you can do your daily rewards and even class challenges. It will make you better prepared and helps you practice or get warmed up.