SABATTI double rifles

Mine is 45-70 and was ground in right barrel muzzle a little. All i did GROUND muzzles back 1/8" and it was gone. Then recrowned them. Friend that hand loads for me started shooting it with his favorite load for RUGER #1! Some tweeking was needed and then. Wooooooow you cant believe this, but at 55 yards it shoots LR-LR 4 shots in a rugged hole. NOW tell me what did i do wrong, so it comeout right ?

SABATTI DR are very well built !