Have you fired the HK 416? Do you know what you are talking about? U talk like you have fired hundreds of rounds from a HK 416. If you want the most reliable weapon out there, than hands down its the AK. Like I said, I have fired hundreds of rounds, maybe even thousands from the M16 family. And no problem. I have had m&d and sand in my mags, and still fired the M16 no problem.
I don't count the number of rounds I've fired on HK's range of weapons, but I would like to think I've enough experiences with them, and I stand firm on my preferences and comments on them.
As for the AK, I've used it a couple of times, simple and reliable but didn't like it much, sure there are people who swear by it, but not me. And this would be because [FONT=Geneva, Arial, Helvetica, sans-serif][FONT=Verdana, Arial, Helvetica, sans-serif]
optics require special adapters[/FONT][/FONT] and I don't like the safety [FONT=Geneva, Arial, Helvetica, sans-serif][FONT=Verdana, Arial, Helvetica, sans-serif]
mechanism.[/FONT][/FONT]
M16s are great out of the box and in a range, most civilian owners would not have any issues with them, especially for the later versions.
However, my experience with them in the field are less then desirable. Mostly due to issues with feeding, failure to extract, rim-sheer and choking of the gas tube but this could be due partly to the environments where I was deployed and the rounds I was getting for them.
Mag problems are not attributable to problems with the upper receiver group. If the mag springs are bad, than its bad. Nothing to do with any upper receiver. Do you even know what is an upper receiver?
It would be interesting to think that mag springs play no part in feeding the weapon. Weak springs could cause a jam.
If you know anything about FIBUA, you will know that barrel lenght has nothing to with FIBUA. Its the lenght of the whole weapon, not the barrel alone. U can have a short barrel, but if the rest of the weapon is long, than its useless. The SAR-21 is a bullpup design, that makes it short, much shorter than most other weapons out there and therefore, more maneuvrable in a building. The standard HK 416 is 941mm with the stock collapsed, whereas, the SAR-21 is 805mm only. The shortest SAR-21 you can get is 640mm, and the shortest HK416 u can get 701mm. Go back to your armchair schoolboy.
If barrel length has nothing to do with FIBUA, try bringing a Barrett into a building next time. However, you're right to say the length of the whole weapon plays a part.
I don't have the measurements of all 3 weapons at the back of my head and my experiences with the SAR-21 has been limited to the range. Didn't know the had a 640mm version, didn't see it back then and certainly didn't have the chance to use it.
But having said that, there is only that much of length you can trim from your butt stock before the weapon starts to feel funny in your hands. Ultimately, there is a length on your butt stock you need - or are used to - which helps you operate your weapon with greater efficiency and accuracy.
I'm tall with long arms, and would prefer my butt stock fully extended mostly, hence a shorter barrel is my option and preference.