***Long Winded Bast*rd Alert!!!***
M-16 jam all the time, AK-47 jam less often.
If the end user is an undisciplined and/or poorly trained soldier, then I would agree. The M16A2-A3's perform rather well in all environments provided the soldier is trained on proper cleaning and their NCOs ensure it is being done on a daily basis. In the desert, for examle, normal lubrication proceedures (for a temporate climate) tends to attract grime, and will cause malfunctions, so we learned to use only a tiny amount of lubrication on only the necessary moving parts (I personally used a 'tuff cloth' teflon/silicone based product). Consequently, I have never experienced a jam related to weapon cleanliness-ever. I have experienced one (in a 10.5 year period) "double feed" jam due to a magazine with a defect.
Also, While in Bosnia, I was doing a joint range with the Russian Airborne unit based out of Camp Uglivek. We fired each others small arms, and even though we brought twice the ammo they did, our M16A2s M4s M24s and M9s experienced zero malfunctions (even though the ARs were fired in burst until smoke was rising from the handguards), and they had three AKMs and two SVDs go down...and they were literally dripping with lube. Poor manufacturing quality catches up with you eventually, I guess.
Aynyway...Unless you wanted the player to be an undisciplined conscript type soldier, I wouldn't even bother with a jam script for assault/small arms. For SAWs and light/GPMGs I would work it in though.
Also, I have already done a script that simulates barrel heating/changing. It tracks cumulative heating and cooling of the barrel based on a user definable "heat unit" per-round variable. As the player fires, the "heat" will build up, pauses in firing will slowly allow the heat to "cool", so short bursts will not overheat the weapon. Changing the barrel will reset heat to zero. If it overheats, increasingly darker smoke will start coming from the barrel until the heat becomes too great causing catastrophic failure as well as injury/death to the firer. Remaining rounds in the magazine will cook off (camcreate'd setvelocity'd rounds of the type in the magazine), possibly killing anyone around. I'll post it if there is interest.
-Grendel