Just for some context, I found this small caliber bullet in the shoulder of the cow elk I shot this winter. You can see it’s fully flattened out and it’s jacket was nowhere to be found. There was no evidence that it ever hit any bone, either. I put my calipers on the nub of a base and would guess it was 22-24 caliber at one time. I presume that the elk would have likely survived and healed up just fine. The other bullet is a 225 Sierra Prohunter I used in my deer/elk rifle chambered in 338 win mag to kill the elk. In terms of appropriate dual purpose cartridges, folks have offered some excellent recommendations. They all work with the right bullet but I’ve found often that with elk a bigger bullet is more likely to be “righter”.