Mauser Karbiner 98k
Previously in DOD this was a weapon for masochists or the severely 1337 like yours truly. Now with the new aiming system it has become far more popular. I've even had cases where I've been told in a server than the maximum number of Grenadiers has been reached, forcing me to pick another class.
The reason it is now so popular is due to the unerring accuracy of the rifle, combined with its power and the steadiness of the cross-hair. The moving part of the cross-hair is very quick to come to rest, is smaller than the others and it moves less when running. This means that even a shot from standing will almost always hit and kill a target.
The Kar also takes a lengthy period of time to chamber the next round so even when standing by the time the next round is ready the sight is realigned fully. The sight calms almost instantaneously when you stop especially when you crouch, this means you can quickly pop a shot off at any target with good accuracy. This is great for taking out snipers and MGs and people in windows etc. So basically for longer range sniping find some cover and crouch if possible, but above all remember to take a moment to aim properly and then carefully squeeze the trigger.
At shorter ranges the best tactic is to crouch and fire and you'll need to have good reflexes to pull this off regularly at very close range. When you get too close fire but if you miss you have a couple of options. The first is to wait for the next round to chamber and fire again, the second is to draw out the pistol as mentioned above, thirdly you can go for a melee kill. If you are very close why not lunge with the bayonet instead, with a touch of sprint and strafing you'll be around their bullets and giving them a good dose of steel. In the words of Corporal Jones, "They don't like it up 'em!" Sometimes if you’re both out of ammo the spade kill is more effective but it's up to you to judge when to use it instead of the bayonet.
But drill it into your head to get into the practice of using the bayonet when you are very close rather than firing and waiting for the next round before you can lunge. It's better to lunge miss/wound and then fire. I often wait around the corner if I hear someone coming ready to jump out and bayonet them at the last minute.
Garand and Karbiner43
This gun is a brute to master, one could almost say that it is to DOD 2.0 as the Kar was to 1.3. It takes a fairly short time for the sight to align after movement and can manage a shot from standing with accuracy. Unfortunately the recoil is very high and you'll be fighting to pull the cross-hairs down onto the target again. To combat this you should crouch to fire at all times unless you are just firing a single shot.
If you sight a target hit crouch aim and fire don't necessarily fire as fast as you can take a slight pause to make sure each shot is aimed and keep shooting a target until it says on the screen they are dead. The Garand is ideal for Fire-and-Movement as you can pause fire a few rounds and move on and repeat this to maintain strong suppressive fire. Be warned though this gun is very rarely a one shot killer. A shot to the head or chest will most likely kill but always try to fire two bullets at least to make certain. When shooting at heads in windows it is very effective as you can fire fast and pretty accurately and catch the guy in the head. This is invaluable on beach maps where you have enemies in the bunkers above you.
Prone recoil is practically eliminated which allows you to easily double-tap
enemy soldiers (fire two round shots). This gun makes a pretty good medium range
sniper weapon in this configuration as it has a high rate of fire and pretty
fair accuracy and will even hit fairly distant targets. At longer distances
you should always try to fire more rounds as some are bound to miss in most
cases.
It is an OK weapon up close but you may wish to pause and crouch fire rather
than dodging and firing or switching to the pistol. Make sure up close that
you make your shots count, aim for the chest and keep firing.
The only differences between the Garand and K43 are that the rate of fire of the Garand is slightly higher. This means that in practice the K43 has higher accuracy because you are forced to wait longer between shots meaning you have more time for recoil to subside and to realign the rifle. This makes it better than the Garand at longer ranges. Couple this with the fact the K43 has a more powerful bullet and it is a very effective medium range weapon and is also pretty nifty at longer ranges. Close in though it's more a matter of making each shot count, take your time crouch when firing and then dodge between shots.
Allied Thomson crouch firing, notice how due to sprinting the Axis Heavy
Infantryman has dodged the initial burst totally