Anyone install a Shilen match.22 RF barrel on the B14R? A customer of mine was inquiring about putting a good barrel on his and I have been happy with 2 Shilen barrels for my RimX. One heavy with barrel nut arrangement with my own chamber and a light weight from Gardner Precision with JGS Match chamber. Both are excellent shooters and beat my 2 Anschutz rifles. Is tennon metric or standard?