I will cover all the competitive guns.
MP7: 40 ammo, low recoil, good for pre-firing and headshots. Can be silenced, has decent damage and range. Basically this is the gun you would use to rush and prefire, takes more shots to kill but is easy to use.
Versek: 30 ammo, high damage, armor penetration, high recoil and bloom, and cannot be silenced. This gun is the gun you want to use to kill people quickly at close range, but is terrible at a range. Good for rushing CQC only.
M4A1 Mk3: 30 ammo, low recoil, medium bloom, decent damage, high rate of fire, good range, and good mobility. Good for headshots and outguns XM8 at close range due to the rate of fire.
XM: 30 ammo, low recoil, low bloom, high damage, medium rate of fire, great range, and decent mobility. Outguns almost all rifles long range and has good knockback power. Loses at close range to most rifles, but has a good headshot ability for 1 hitting.
Para: 25 ammo, high recoil, high bloom, super high damage, armor penetrating, good range, and good mobility. The hardest rifle, but can be used at all ranges if used correctly. Can outgun any gun, but is harder to use than the other rifles.
AMD: 30 ammo, low recoil, low bloom, low damage, good range and good mobility. Decent rifle that is good because of its very high accuracy and aimed in ability. This rifle is good for medium to long range combat and can compete with xm8 at a range. The low damage and only average rate of fire makes it lose CQC to m4a1 and para.
Fr-f2: good 1 hit ability due to armor penetration. Fast quickscope and quickswitch. Not good for wallbanging at all.
TPG: Best one hit ability. Slow scope, decent quickswitch, great for wallbanging.
ASW: Great one hit ability, silent, fast quickscope and quick switch. Good for wallbanging.
PGM: Good one hit ability, good quickscope and quickswitch. Good for wallbanging.
Comes down to preferences.