On Replacing the M-16

Here's about everything you ever wanted to know on the evolution of the military's most common weapon, the M-16 (and the shorter but increasingly common M4 carbine). This rifle has evolved over 50 years to become a very effective and accurate weapon, but some folks say the Army needs to replace it.

The article says:

The latest developments? The M4 and 3 competitors, including one M4 variant that can be converted from existing rifles, come out of a sandstorm reliability test – and the M4 finishes dead last, with more than 3.5x more jams than the 3rd place finisher. But the US Army publicly says that it doesn’t care, and orders more.

I was always a fan of the XM-8, which contrary to popular opinion, I thought was a beautiful looking rifle. But in the end it may have been overreaching, so perhaps something like the HK416 would be a good compromise? There's also a debate on whether the caliber (5.56mm) is sufficient. So perhaps a slightly bigger 6.8mm round in an improved rifle is what we're looking for.

Maybe some military types out there have an opinion. Anybody care to comment?