I had my first Sig 556 come into the MGC shop for an ultra sonic cleaning. He complained that it felt rough. Well it was a little dirty and bone dry with the exception of the original white lithium grease. Well, yeah. That will slow things down a bit. Well, I got it all clean and oiled (with Slipstream of course) and back to the customer. Sadly it really didn’t feel any different mostly due to the heavy buffer spring weight.
A few minutes later the customer comes back out of the range complaining that it will now not cycle. The customer twists on the piston end cap and it comes off. It wasn’t locked down in the captive notch. So I redid the cap and we took it back in to the range. BANG, BANG, BANG. 15 rounds later we pronounced it healed of the evils that afflicted it.
End opinion…not wholly impressed. Good weapon when maintained properly…like most modern sporting arms. Just clean and lube your guns, brothers and sisters.