Different XP Gains?

I was just wondering if there is a different formula for how different people gain XP or something, because I’m seeing a lot of discrepancies in XP gains.

I played a few rounds of Infinity Slayer with a friend (who is a higher rank than me), and he would average about 200-300 more XP than me per match, even though I was getting more kills and less deaths than him.

On a side note, there is something similar in Halo: Reach. I need 220,000 XP to get Brigadier, but a (different) friend of mine only needs 150,000 for General Grade 2.

Why are there differences in XP, and why do I need more? Or am I just crazy?

Just because you are getting more kills does not mean you are getting more points. EXP comes from game completion, winning, and your score. Your score is all the points you get from a game, style kills, assists, sprees, etc. Any medals you earn get you more score. Maybe he just gets a lot more medals than you.

It’s just Slayer, I got more kills, assists and medals of all kinds. No objectives to hold or anything.

Bump.