I'll not comment on the little rifle...
But there is a difference in the .223 Remington chambers and the 5.56x45NATO chambers. The 5.56 have longer throats from what I understand and the NATO ammo is loaded to operate in those chambers. Using 5.56 ammo in a .223 chamber means that you could be slamming the round's bullet up against the rifling which of course would increase pressures.
Same thing for .308 Win and 7.62x51NATO chambers.
If your rifle is chambered for the civi rounds, you just don't use milspec ammo. If it's chambered for the milspec ammo, you can use both milspec and civi ammo with no prob.s.
Both of my AR's have the 5.56 chambers - a Bushmaster XMP-15 and the Stag lower/del-ton upper kit rifle shown up-thread.
And as far as camps of gun nuts, I have a foot in most all of em
Evil Black Rifles - AR's, AK's, FAL, SKS, etc.
Bolt Action "fudd" rilfes
Lever Action Rifles -
![Smile :)](./images/smilies/icon_smile.gif)
Military Surplus Rifles
Single Shot Rifles
Pump Shotguns
Semiauto Shotguns
Single Shot Shotguns
Black Powder muzzleloaders and cap and ball pistols
Old revolvers, new revolvers
Old semi auto pistols, new ones
I like em all!
![Razz :P](./images/smilies/icon_razz.gif)