Carbine
I won't go into too much depth on the carbine because it is very similar in most respects to the Garand. Basically the only difference is it has less power, recoil and accuracy, a larger clip and rate of fire. This again is a gun that must be used from a crouched or prone position. Unless you are very close where the high rate of fire make up for it recoil and you can often achieve a good "Burst" of fire.
You are still better off stopping crouching aiming and hammering away on the fire button whilst keeping the cross-hair on their chest. Even when you come face to face with an enemy at medium range this gun is deadly if you crouch and start firing, you should either force them back into cover allowing you to displace to a less uncomfortable location or you'll kill them, occasionally they may even get the drop on you instead :D
I'd recommend rather than double-tapping at enemies with this gun you should be emptying the magazine until it says they are dead. Don't worry about ammo you have plenty of it and if you run out you should be able to die happy knowing you've killed the equivalent of the entire enemy squad at least 3-4 times. At longer ranges this gun's large clip and high rate of fire make up (to some extent) for its fairly low accuracy. This is a great close-medium range gun and is also relatively practical and medium to long ranges.
A note of warning as mentioned in the grenade section the Para version of this gun features a folding stock. This means attempting to short fuse your last grenade is something only to e attempted if you are rated expert in grenade throwing. You'll have just enough time to pick it up and lob it through a 1st floor window if you can scoop it up, aim and throw in one smooth movement.
MP40, Thompson and Greasegun
These guns are very popular and until I actually started playing with them regularly to learn how to use them effectively I couldn't understand why. At long range these guns can be pitifully inaccurate and an entire clip fired from prone may result in 2-3 hits! With some practice though things can be improved significantly
To start with these guns have very little recoil and can be fire with a fair bit of accuracy from standing and whole clips can be emptied into one spot. So long as you aren't moving you'll get pretty good results. If you crouch though you're accuracy improves as does the recoil. It takes some work but you soon learn how to keep the mouse moving to hold the crosshair on target against the recoil
To ensure kills just empty clips until the kill message appears. Some say to fire in short bursts but I find that you are better off firing in half clip bursts most the time. Aim at the belly of your target and recoil should carry the burst up their body hopefully putting rounds into their chest and head. At close range just aim at waist height and start spraying and hope the recoil takes the muzzle in the right direction so the target is riddled with bullet from groin to forehead.
When lying prone in a good vantage point these guns are pretty effective as a mini-machine gun with just the problems that you'll have to reload fairly regularly. As with most guns whilst prone there is virtually noticeable recoil but accuracy is quite low and hitting your target requires as many bullets as you can give them.
The Greasegun has a much slower cyclic rate and therefore it is more effective at longer ranges. This is because you have more time to adjust the sights between bullets. It also appears to be extremely accurate and in the hands of some players I've see them outshoot snipers with scopes throughout a game. Because of its unique accuracy and rate of fire it can also be fired pretty accurately whilst strafing from side to side making it a pretty good assault weapon.
Remember short fusing grenades with the Greasegun is not easy and should only be attempted by experienced players as I mention in the grenade section.
Always be ready to whip out your side arm when at closer range and you main
weapon needs reloading. As you can see the entire clip was emptied to ensure
a kill