I'm shooting a Model 12 BTVS 223 with reloads I see a consistent .500 average have about 700 rounds down barrel in time I want to purchase a Shilen match grade barrel whats my odds of getting less then .500 with a Shilen.??

I've been advised to use a custom barrel eliminate the locking lug, Squaring off the receiver face, lapping bolt lugs, install custom recoil lug and recrowning would possibly get me down to .250, thoughts.

I've never changed out a barrel or had any custom work done on a rifle.