I really like my Oly.
Ahem... I wonder where I could have bought mine...I ran 1500 rounds in one morning through an Olympic M4 post sample. Most all shooting was done full auto with absolutely 100% reliability. We were using 4 or 5 different style magazines and at least 4 different brands of ammunition. This was part of a SWAT TV episode and since we ran the drills continuously I was unable to load mags and relied on a crew to keep mags loaded, sometimes to 28 rounds sometimes all the way to 30.
You can't go wrong with Olympic.
I agree with the rest you can't go wrong with an Olympic. If you do get one with a tight chamber, call them and send it back. I've been told by the guys a Bradis they carry a lifetime warranty. Olyimpic's website claims that all their barrels are match grade. And as said before. mine seems to be just as accurate as a Rock River.