Hi guys, I am in the process of reducing my gun collection, and I have two rifles converted to fire the 45/70 cartridge. Before I can sell them, I need to find out why they don't shoot that well. One rifle is a British No.4 Mk2 and the other is a French Mas 36. They both have been fitted with the same Shilen 45 caliber black powder barrels. They were installed by a professional gunsmith. I have not fired black powder loads through them, but have tried smokeless loads that work very well in my Sharps rifles, i.e. 14.4gr of Unique/405gr lead bullets/gas checks . Bullets seem to hit very wide, 10 inches at 50yds, sometimes hitting sideways. Anybody have any advice on this? When I slugged the bore, the dimensions seem to be almost the same as my Sharps, and I believe the twist is 1 in 18".