First of all, the Diemaco C7 rifle is a licenced copy of the M16A2 with a few exceptions in difference. The early problems with the M16 was the propellant in the US M193 ball ammo used in the 1960s. That has long since changed, and the ammo has improved, along with changes and mods to the weapon itself, the most important a new heavier bullet (SS109) and a different rate of twist in the bore (1-7, 1-9 are most common, with the A1 version having a 1/12. C7s are 1/7".
Currently the M16 family of weapons has been in service for almost 40 yrs, and its the most combat proven 5.56 x 45mm rifle in existance, with all the bugs worked out of it pretty much anyways.
I have extreme confidence in the wpns system, and I would carry it anywhere in any theatre anytime.
Now the AK family. Firstly, the AK74 series of 5.45 x39mm weapons has too been around for many years. The AK-47 in 7.62 x 39mm was a solid rifle with a machined reciever from solid stock. In its original configuration, it still will be encountered anywhere in the world by the bad guys or . It was first introduced back in 1947, based on 'asistance' from captured German engineers (remember the MP44) with some Soviet assistance from 'Mike' Kalashnikov.
I recently examined about 15 AK47s, some Russian, and some Bulgarian which were captured by our (Australian) military forces in Iraq. Also there was a large quantity of Russian, Chi-Com (Type 56, and Type 56-1s), Polish, and Romanian AKMs too. All jealously marked in arabic characters on the wood. These are deemed for museums in Australia. All were well used, and had mix matched parts, as even com-bloc wpns have the body cover serialised along with the gas tube assembly, etc. Wherer as the C7 and US M16s only has the lower reciever serialised. Australia serialises the upper and the bolt carrier at Army base wksp level.
With hen FN C1A1 rifle. The M16s used in the VN war were mainly A1 versions made by Colt and GM, along with ealy XM16E1s, which strangely enough may still be encountered (upgraded to A1 specs thru attrition back in the 1970s), as the A1 is still in the system here, along with the A2, and M4. Ordering ammo is a nightmare because the A1s use the older M193 ball, while the A2s and M4, along with the F88 Austeyr use the 5.56 NATO SS 109 ammo.
In 1959 a lighter modified version of the AK was brought into service by the Soviets, called the AKM. A few simpler design changes, mainly the use of a stamped receiver and ribbed body cover, along with 1000m rear sights, a funky angel cut muzzle break, and the provision for a proper bayonet.
Then in 1974 a new type of AK was first seen by Allied Forces in the November military parades in Moscow. The calibre of this was the new 5.45 x 39mm, which was designed to compete with the US 5.56 for accuracy and lethality. The rifle gained popularity in Afghanistan, and again differs slightly from the AKM. The main differences are of course the calibre, an improvement in the bolt, a new muzzle break, and different stock design. The folding stock version folds sideways, and is more robust than the traditional MP40 style folding butt on the AKM and AK47.
The AK74 and its variants can be quickly identified by either orange or black bakelite/plastic type mags, which are not as curved as its 7.62 x 39 cousin, and of course the extended unique looking muzzle break. The rear wooden butt is also slightly different with a groove down the side of it. Recently a new upgraded spear point bayonet has been brought into service. It still cuts wire, and is either black or plum in colour. Its made in Russian and Bulgaria, and has a new ergonomic style of grip, similar in fashion to the ridges on the US M9 bayonet. It will fit on any AKM and AK74 rifle.
Overall the AK family of weapons are traditionally robust and the use of them is easily taught to inferior less trained troops, so even the village idiot can figure it out.
As for the safety, its located on the right hand side of the weapon, and unique to the AK, the first click down is Automatic, and the second click is semi-automatic. On the downside, try moving the safety with gloves, or worse, with the under folding stock on the AKM and AK47 with the stock folded, try moving the safety with gloves on again. Its difficult. There is also a distinct 'clack' when the catch is moved, and this no doubt can be clearly heard on a quiet night.
The sights are traditional following in the PKM GPMG, SKS carbine and M1891 rifle style sighting pictures. The AK74 rifle has an effective range in par with the 508mm bbl M16A2/C7.
The AK also has a LMG version called an RPK in 7.62 x 39mm, and RPKS74 in 5.45 x 39mm. The receiver is slightly more reinforced, different rear sights, and longer bbl, folding bipod, and different butt. There is also AFV short barreled versions too, one being called an AKSU.
Russia is currently pushing yet a new version of the AK74, with Picatinny rail,and the use of plastics instead of wood. The rifle is evolving too, along with its NATO/western counterparts, the Russians too must keep up with the Jones also.
To sum up, the AK is a very good rifle, but has its limitations (no arctic trigger for example), and I too would feel confident to carry and use this weapon in any theartre.
Hope this info helps ya out, and I am sorry for any spelling mistakes as for a while yet I cant edit.