If you are going to use a PowerBelt on elk, the 444 grain flat point is the ONLY one worth considering. Do not use any hollow point, or polymer tipped hollow point PowerBelt bullet on elk and expect good results. I have witnessed a failure at 28 yards on a real nice bull that we called in. The bullet obviously blew up and never entered the body cavity. The guy never had a problem with that load on whitetail, but elk are not whitetail. They have about 4-5 times the mass than a whitetail, which includes all the bones.
The hollow pointed Great Plains bullets or Any hollow pointed hollow based bullets are a poor choice, IMO. I like the Hornady FPB for deer, but would not be my choice for elk, even though I know guys that have great success with them on elk.
Personally, I would find a different rifle to hunt with that will shoot a No Excuses/Bull Shop/White Power Punch (Super Slug), than to hunt elk with any PowerBelt other than the 444 grain flat point.
If you're lucky, you may get one opportunity, you need to make it count. If you are going to be calling in bull elk in dark timber, they usually come in straight at you or slightly quartering to, you need a bullet that is capable of breaking bone at close range if need be. I have shot a slightly quartering to bull elk through the big heavy ball and socket in the front shoulder with a 435 grain White Super Slug. Took out both lungs and the plumbing off the top of the heart. No way any hollow pointed Power Belt/Great Plains/Buffalo Bullet would have ever made it into the chest cavity, at least not in one piece. Maybe some small fragments?