Even if you could get a bit more out of it, I wouldn't want to shoot at a deer and past the 150 yard area. A few years ago a guy next to us(neighbor) wounded a nice buck with his 20 ga slug gun. He described the shot as a bit over 100 yards.
For the longer ranges I much favor a modern inline muzzle-loader, where center fires are not allowed. I did a 'shoot-off'(informal) this Fall between my slug gun and M-L. As expected the Knight Elite in 45 cal handily outshot the Browning Gold with the Hastings slug barrel. Just a few musings on the subject.