Unless you buy a premium barrel, Krieger, Bartlin, Brux or the like, and blueprint it and the action, I seriously doubt you will see anything but disappointment. And as far as I know, none of the premium barrels are offered as a pre-fit, so you are almost guaranteed to buy a lesser barrel than you already have.
I built a Mauser with a budget ER SHAW barrel trued the action, the bolt face the shoulder and was VERY happy to end up with a sub MOA gun. It has never shot a 1/4 inch group.
There is a learning curve, and you need to be able to deal with such issues as tolerance stacking, and action truing.
I would be exceedingly surprised to see a 1/4 moa rifle come out of a first timers effort.
If you forge ahead, buying a short chambered barrel and reaming to a good headspace would be the method of choice.
Much harder to screw up.
And you can rent most reamers
Here
Have you considered sending it to someone and having it set back?
Have you been inside of it with a borescope to see if you can figure out the issue?
Given the round count, the throat is the most likely suspect,setting the barrel back and cleaning up the chamber and throat, and maybe a re-crown while your at it might be an option, allowing you to keep your very good barrel. .
Spend your money on a good smith instead of a cheap barrel.
ETA: No one here, especially not me, is trying to discourage you from learning to rebarrel a rifle, or develop your smithing skills. I am a rank amateur compared to most here, and certainly the only way to learn is to get experience.
The point is; you already have an exceptional rifle, and improving what you have is a very tricky proposition best undertaken by an experienced and highly skilled smith. I, and I expect most here would be thrilled if I ever turned out a 1/2 moa rifle. I would dance a jig and call everybody I know.
If you want to work on your skills, start with a rifle that really needs improvement. Building a 1/4 moa rifle is the field of a very few masters.