Hey there bullaboy -- Welcome to Marlin Owners. Congratulations on your new (old) rifle. I have no experience with this bullet. If you haven't already bought the mold, you might consider running a few bullets in the 250 grain range through your rifle and see how they play. You may find joy there!! I always seem to be trying to stretch things further and the heavier and longer bullets seem to work better in this regard. If you do go down the #37583 road, let us know how it works. That mold is available over on the SASS wire classifieds as we speak. Best regards. Wind