I'm looking for advice from the balistically gifted on this one. My first question is if I'm shooting or planning on shooting slugs at around 1100 fps do I want LW's air rifle barrel with a 17.3:1 twist rate, which if I'm not mistaken was designed for pellets, not slugs? The other option would be a straight, no contour target barrel in .25 with a 10:1 twist rate as long as the half of the barrel that fits into an Impact can be turned down to .550" But for now lets assume that is an option. Which would be the best choice?