Ok, Have read the ammo oracle....and I understand the functional difference between the .223 Win round and the 5.56 NATO round. I have a Bushmaster chambered for 5.56. I know that I can safely shoot .223 ammo in this rifle. My question is...for those that have shot enough of each to compare...is there any noticeable difference between the two?

99.9% of the time, my target will be a piece of paper, a tin can, or something similar.
Most of my target shooting is from a standing position, so MOA accuracy isnt a huge concern...

This is my SHTF weapon. I have used Q3131A or XM193 since I owned it, but am now considering a bolt bench rifle in .223

I have access to bulk .223 ammo and at around the same price I am paying for surplus 5.56.
What can I expect if I make the switch to only shooting .223 through my bushy?

Im guessing there will be no difference at all, but I figured I would ask, since I havent spent the money yet. Also, I dont reload, and dont plan to for some time (eventually I will, just dont have a set up for it yet)

Thanks

I also have a Bushmaster chambered in 5.56.  Here is what I found.   Everytime I use 223 ammo, I have cycling problems.  I NEVER have problems with 5.56 ammo though.   I believe the 5.56 packs a bigger punch than the 223 and therefore seems to cycle my gun better.   Im no expert, but I cant help what I have found for myself.  

A 5.56 chamber is slightly larger than a .223 Match chamber.  This is so the rifle will still function if the chamber is dirty.  There is no negative outcome to shooting .223 in a 5.56 chamber, except some people say the casing expands more and it is not good to reload them.  You would not want to shoot surplus out of a .223 Match chamber because the tolerances on 5.56 are not as tight as .223 ammo.  There is a slight accurancy differance between the two chambers, being .223 Match chamber is more accurate.  The difference isn't noticable, as most people aren't capable of shooting as good as the rifle is capable of.