Are you buying factory ammunition or loading your own?
There are many great bullets out there for elk that I wouldn't hesitate to hunt elk with. As mentioned earlier, it just needs to shoot well in your rifle. I've killed elk with Nosler Accubonds, Berger and Hammer bullets. They all worked well. The Nolser partition is a very good choice if you are not shooting more than 400 yards and want a bullet that is effective and reliable.
There are a couple advantages to the all copper bullets like barnes, hammer, etc.
#1 - More likely to get and entrance and exit hole.
#2 - No concern about lead fragments in meat.
The advantage to bonded bullets like Nosler Accubond, Hornady ELD-X is more hydrostatic shock with reliable penetration. That hydrostatic shock tends to drop animals faster. The only 3 elk that I've killed that dropped in their tracks, were with Nosler Accubond and Berger bullets. Barnes and hammer bullets still kill the elk well but they are more likely to stay on their feet for a few seconds after shooting them.
Some people really like the non bonded bullets with thinner jackets like the Bergers or ELD-M. They will provide excellent hydrostatic shock but there is concern about penetration. They can still be excellent bullets for elk as long as you don't expect them to perform in ways they will not. For example, a guy shooting a 6.5 Creedmoor at an elk at 1000 yards in the shoulder with ELD-M and being disappointed it didn't penetrate the shoulder.
My main gun for elk is a 300 Win mag that I load with 199 gr Hammer hunters. I'm often taking my 338 Lapua with 300 gr Bergers or old 300 win mag with 180 grain Accubonds as a back up guns on elk hunts.