TIA.

The guy I bought my lower from has a 300 FB; said he builds all his rifles from oly products.  He seemed very satisfied with the weapon in terms of accuracy and punch.  Your expectations should also depend on which style of barrel you're getting: SUM, SS, CM (Im nearly positive that all 3 are available in .300).  The SUM barrels are more expensive but have a very good reputation for accuracy, though Ive heard people say that they're MOA with SS or CM oly barrels too.  

You might get more and better responses from www.oa2.org the oly arms owners site.  

I just emailed Skip Fletcher at OlyArms about the .300 FB barrels and his answer was :

"We are out of stock on those barrels and will have some later in the year thanks"

Anyone know what modifications would be necessary to a .300 Upper to allow it to fire subsonic ammo ?

Zeme
Alaska