Shaving like that looks like a timing issue or too small of an opening on the forcing cone. With the trigger pulled and the hammer held back; do you have side play in your cylinder? Some minor play is OK, Also get a wooden dowel as close to barrel diameter as possible and still slide relatively easily down barrel. Push dowel down from end of barrel and see if it slides flawlessly all the way to the back of the cylinder, try on all cylinders. If it hits the front of any or all cylinders, you have a timing issue. My 357 SM has been shooting heavy loads since 1992 and is a little loose, but it still doesn't shave lead. That degree of shavine; especially with jacketed ammo is dangerous as the striking of the forcing cone off center causes excess back pressure in the cylinder. Don't shoot it again til you have it fixed.
