I had a 221 FB. Built on a R700 action that was a factory 223 action. It would not feed properly and it would not eject empties. I ended up re chambering back to 223. That was an expensive build.
After learning that, I had a 20 VT (221FB necked down to 20 caliber) built on a R700 that was originally a 221 FB. It works great.
Unless you have a R700 action that was factory original 221 or 17 FB, you will have a very unreliable rifle, if you chamber it in a 221 size cartridge.
An alternative is the Sako A1 action. I bought one in 223 and had it rebarreled to 221FB, it functions perfectly.
