I don't think many people here subscribe to that theory, as the predominate opinion here is that one should use the slide-stop instead of the sligshot/overhand method on handguns. I can't imagine they'd change opinions because:carbine.
So you raise a good point, which is that what we're talking about for the charging handle is initial loading and malfunction clearing.
I have literally never seen a Colt OEM CH break from one handed use. I'm not saying they can't or that others haven't seen it, but I personally have not seen it. I threw my CH out every 20,000 rds, along with the rest of the upper. Along with 100 other M4's. Maybe that counts as PM, IDK.
Now Anderson is getting into the act:
http://www.brownells.com/rifle-parts...FEY3RiNElrPSJ9
BCM OEM now down to $899 at Brownell's:
http://www.brownells.com/rifle-parts...?sku=100019539
Sent from my iPad
Likes pretty much everything in every caliber.