That's going to vary gun to gun so it's hard to say.
Factory BLR triggers are among the most horrible triggers I've ever encountered. I find it difficult to determine what kind of accuracy the gun is capable of when fighting such a nasty trigger.
That said, from a bench, with good optics, some BLRs will shoot well under MOA. Others ... not so good at all.
I know Neil Jones has done some BLR triggers, whether he still does or not, I'm not sure, nor do I know what he's charging for that work. His web site is
http://www.neiljones.com/ ... you can use that to contact him. He's done some really nice work on (Remington, only, so far) triggers for me.
Tom