If you want realism, why not? Guys (including myself) who run with GBBR's all have limits on our magazine capacities. My M4 is limited to 39 rounds. Yes, it's a disadvantage against guys who have endless ticklers, but it's realistic. I run with 4 magazines capped at 39 rounds with no issues, and I still manage to get my share of kills.
It'll actually force you to move around and not camp in a single spot the entire game with one finger on the trigger and the other tickling the magazine.
Unless you want to do what they do in Hollywood movies and never have the need to reload - do it!
Age Verifier - Unionville and Markham.