I have a 527 I re-barreled to a 20 VT with a Douglas premium stainless barrel. I love it, it shoots great and I put a maple CZ stock on it to dress it up. Ridiculously accurate - but not sure I can part with it. If you decide to build one - get a .221 Fireball and re-barrel with a good quality 1:11 or 1:12 twist barrel. Add 32 gr bullets and some RL-7 and be very happy with minimal recoil & great accuracy. This may be the best cartridge that has never been made in a factory chambering.