25Q trying out for RASP; what does a 25 Series actually do once in Ranger Regiment?

You will essentially lose the Q and just become 25... cross trained on commo, but you will be trained on the infantry side as well. If you end up a CO'S RTO like a buddy of mine I went through RASP with in 2011, you will go out on missions, you will fight, you will be there every step of the way.

Sua Sponte!

You'll do both. If you earn your beret, you'll do 25 series stuff, not necessarily 25Q. You probably won't be kicking down doors on raids, but you may be attached to a platoon at some point, especially during training missions or remote outposts.
It's like in Starship Troopers, everybody fights, everybody works.

SPC (Join to see) I'm a 25B and am currently a commo chief (U or C slot) in 3/75 with 4 RTOs under me. 1 is a Bravo, 2 are Charlies and 1 is a Uniform. If you make it through RASP and into Regiment all they see is 25 Commo. They will put you where they need you. Could be straight to the line, the S6 or over at RCC. If you do make it to a line company you will do all the training with your platoon just like everyone else, you’ll just have to carry a heavy radio with you. Best of luck and don’t quit!