I crimp everything.
I built and used hot 296 loads with 300-325 grain lead bullets for the .44 mag for several years; used them a 4" Model 29. New Starline cases, turned-down expander. There's no way those bullets would stay put in that revolver without a serious crimp. The 6th round in the cylinder would creep. I saw the exact same thing with heavy 325's in the .45 Colt, when fired from the 5 1/2" Blackhawk.
For the loads mentioned in the paragraph above, I eventually went to a two-stage crimping operation, using a Lee FCD and finishing with a 'bump' into an RCBS roll crimp die. The crimp made the difference; the slugs stayed put after that.
Talk to Buffalo Bore, Garrett, Corbon or any purveyor of heavy hunting loads. Ask them if they run a heavy crimp on their loads.
“Nine-tenths of tactics are certain, and taught in books: but the irrational tenth is like the kingfisher flashing across the pool, and that is the test of generals. It can only be ensured by instinct, sharpened by thought practicing the stroke so often that at the crisis it is as natural as a reflex.” ~ T. E. Lawrence