I have no experience with Sanders. I have a Grendel Hunter BCG that works well. Grendel Hunter uses a Satern Liberty barrel, and I have one of those too. After a couple hundred rounds of break in, it can shoot five shot groups under an inch. It's consistently under 1.5". At yesterday's prices, it was no big deal to run Wolf Military Classic through it to break it in. At today's prices, just start with a well-finished barrel.
Rack grade makers occasionally turn out barrels that shoot very well right away. Custom finishers occasionally turn out barrels that don't shoot well. However, the good custom finishers usually turn out barrels that shoot very well right away, and rack sellers don't. If you want excellent odds of getting 1 moa or better accuracy without extensive break in, you have to pay and wait.
Rack grade makers occasionally turn out barrels that shoot very well right away. Custom finishers occasionally turn out barrels that don't shoot well. However, the good custom finishers usually turn out barrels that shoot very well right away, and rack sellers don't. If you want excellent odds of getting 1 moa or better accuracy without extensive break in, you have to pay and wait.