In a 450 Marlin (ballistic twin to the 45-70, just uses a belt instead of a rim) I use RCBS molds to make 45-300FN & 45-405FN slugs. Both are flat nose design and performance on several deer is excellent with most dropping within a couple of steps of impact. Unfortunately I've never been able to retrieve a single slug, getting full penetration with all. Cast bullets are cheap and easy to make. I've even used 50 cal muzzle loading balls (.490") pushed through a LEE sizer (.460") and seated over a minimal amount of shotgun powder to produce a "grouse" load that has almost zero recoil. The 400+ gr heavy loads are hard on my shoulder and not necessary for deer out to 100 yards so I rarely shoot those but with cast you can load anything in between.