With Bullseye you can safely reduce the charge. Try dropping it half a grain and see what you get. If I were doing a load like this, I'd start with a 185 grain target load of 3.9 grains of Bullseye and see what my velocity is. I'd then adjust based on velocity and whether the gun cycles.
(You got those loads from the Lyman manual, didn't you? I used their data and got wildly higher velocities than they published. I don't use that book any more.)