Mike, I have always shot my 86’s with jacketed bullets regardless of caliber and not had a problem. I have shot several different 45-90’s, all antique serial numbers, all with Remington 300gr jacketed hollow points, smokeless, at 1450fps. I have never seen a problem with barrel wear, they do shoot with better accuracy than simple cast in a poor bore. With a Lyman tang sight I can shoot a tight group at 200 yards, good enough to take deer hunting. I would not want to shoot hundreds of jacketed rounds thru an antique barrel, but a box here and there is not a problem. If your 86 is in the 141k s/n range the steel is modern and a lot better than my old 86’s. When your gun was new they were selling high velocity ammo smokeless for the 45-90, I would not go there, but standard velocity is 1480fps and that’s what I have been using. Not a recommendation, just what I do with my guns. T/R