Probably won't help, at all, all by itself. You still need to re chamber with a more conventional reamer. Anyway, I meant, like the equivalent of Weatherby freebore, which is a way of increasing velocity by loading to higher pressures but not necessarily, accuracy. BB
edit: maybe the intent was to provide room for seating long heavy bullets way out, without taking away from case capacity? That's what you have, a chamber with a long leade, which was the reason for my comment about Weatherby methods and design. But, it's not normal and the guy should have inquired, before giving you something you don't need and don't want.
