I was messing around yesterday during the snow and picked up a Lyman cast boolit unsized 200 gr boolit SWC and a sized 45/70 case, picked up my micrometer measured and the boolit was .458. My question is is it to light to use as a plinking load out to 100yds? I forgot to add that my bore is .457 and never had any leading with a boolit sized .458