A Couple of things 115 gr will shoot on the BDC at least mine does. If that barrel is a bit off smooth it is usually from some burrs 25 to 50 passes with a very tight patch with JB bore paste will save you a lot of shooting and start polishing the bore a package of FPB hornady conical with a 90 gr load will help to. If you master the bench and trigger pull the gun should be capable of 1inch groups with the load of Blackhorn it likes. Lee
P.S. a TC plastic measure with the cut off funnel on top is all you need to measure with be careful of off brand measures I picked one up because it was cheap and when I checked it was 20 gr + off.
If you check them with a scale 100gr volume is 70 gr by weight the volume measures are set to black FFF powder. Hope this helps.