RPD

The RPD in Modern Warfare 2 handles very similarly to how it did in Call of Duty 4, and is unlocked at Level 4 (Private First Class). A notable difference, like with most firearms in the game, is that the ACOG no longer sways. A rail has also been added which is not seen in Call of Duty 4. The RPD benefits greatly from the Bling perk, which allows players some flexibility in their attachment choices. ACOG and Thermal Scope have their obvious benefits, allowing players to perform an 'Overwatch' role and provide longer-range fire support in most situations. Due to the incredibly clear iron sights, an interesting choice is the Heartbeat Sensor which allows the player a fairly clear view of the sensor even while aiming down the sights.
Stopping Power and FMJ are advised for a player going for a loud and all out attack class, be sure to balance out the RPD with a faster reflex weapon like the M9. Unsilenced with stopping power the RPD delivers two-hit-kills on any part of the body at any range, unless shooting through a surface or against Painkiller. The L86 LSW and the AUG HBAR are the only other automatic weapons capable of this. Players who do not care for an additional attachment may enjoy the perks of Sleight of Hand for the quick reloads and aiming, Scavenger for equipment refills, or One Man Army for flexibility in class choices. Also using Sleight of Hand Pro with the Thermal Scope makes the Grip attachment less necessary. The gun can be a surprisingly good stealth LMG with a Silencer, especially in Hardcore where it can deliver one-shot kills at any distance without stopping power, while carrying 100 rounds of ammunition, this makes it very difficult for the player to run out of ammunition before the player dies, or the game ends. The RPD also has very high bullet penetration, just like the AK-47 in this game, this makes it much easier for the RPD to get penetration kills quickly due to the high damage even without Stopping Power. An experienced player can unlock Extended Mags in a few days, or even a few hours of consistent use.
The RPD has the 2nd highest damage output per second due to the high capacity magazines, but falls short to the L86 LSW due to the lower rate of fire. The RPD's one major disadvantage is its reload time - approximately 10 seconds. The same reload time as the MG4. In this time, the player could fire off almost 2 magazines with the AUG HBAR.
To mitigate the slow reload, and there are a few options available. Sleight of Hand is a great option to counteract the slow reload, not only due to speeding up the reload but also decrease the sighting time. One Man Army Pro is actually faster than reloading the RPD while replenishing ammo and equipment. The Extended Mags attachment places all of the ammunition into a single drum.
Weapon Attachments
Grip
Red Dot Sight
Holographic Sight
Silencer
Heartbeat Sensor
ACOG Scope
Thermal Scope
FMJ
Extended Mags

My Class
RPD-Extended Mags or FMJ
Sleight of Hand
Lightweight
Steady Aim