Gun Trouble: M4 & M16

[Firn]

Ive got to say that some retired officer whose last time in combat was 40+ years ago pontificating about our troops current needs off of what he learned in the Mekong is a joke. The only thing the same about that weapon system and the one we carry on a daily basis is the operating system.

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http://www.ar15.com/forums/t_3_118/6...our_range.html

The real issue is that most of the M4 failures are based on mythology.

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Here are some "facts" about OUR experience with M4's on the range.

- Some of our M4's have well over 200,000 rounds down range. Barrels have been replaced, gas tubes have been replaced, BCG's have been replaced but what sets it apart from the AK47's is that upper and lower receivers continue to function. AK's get to about the 100,000+ round count and rails on the receiver will start to crack. It's an easy fix with tig welding but they crack. We have yet to lose an upper or lower receiver from cracking.

The above post, with a quote from the linked thread, raises for me a very general question:

What exactly is reliabilty when it comes to firarms, specifically issued one? Is a gun reliably because you can fire it after a quick cleaning after having been buried in African sand for decades? When it fires in a bitter Russian winter with little care or after it was dropped from a house hitting the pavement?

What is it's relationship with durability, as witnessed in the M4's upper and lower receiver after so many rounds fired reliably?

Overall it seems fairly easy to stack the deck against or for a specific firearm, by using a tailored mix of conditions.

P.S: I wonder how often just the usual wear and tear without proper maintance or replacement parts grinds down the reliability of a weapons system which afterward gets a name for unreliability.