I recently picked up a 25-06 15" encore barrel that shoots nicely without a break. I had a factory 45-70 barrel (tapered) that I ended up adding a break to and then went to a custom bull barrel with the MGM Tactical Integrate break. I shoot 300gn TTSX bullets at ~2100fps. The break is very nice for that load. Not necessary for off the shelf 45-70 loads. A break for a 250gn bullet at 2500+fps would definitely be on order for me.

If you are undecided and have a bit of time and money for shipping, a phone call to discuss having the barrel built without a break and/or options for adding a break later is also an option.