DB, I agree. However my thoughts are if a poster is looking for to the point info he or she should at least qualify their post or intentions with some facts/information. We are all assuming wide open means 400 plus yards, which in this case the 257 wby. is the clear choice for this application. HoweverI live in an area where 500 yard shots could be regular in most regions, yet very few consider this when picking their poison. A shot of this nature for the vast majority would be nothing more than a hope n' prayer in the saskatchewan prairie's. So to suggest the flattest really would be a bit premature to a hunter that really doesn't need or will harness that requirement.

To the question though. 300ish range or in the 7mm rem mag would work just fine. I also would look to a BT bullet if range shooting is in the equation on deer sized game. If the hunter is buying a new rifle this choice would give some future options for bigger game. But only assuming they never already owned a capable firearm such as 308 caliber, for example.

As mentioned for the 300 plus range the 257 wby. is a great choice for deer sized game. As far as bullets either will work just fine for any mule deer you encounter. So being accuracy is of prime concern when considering which load to use for distance shooting, go with accuracy! If the poster already owns a capable multi species rifle like 3006, etc then buying a 257 wby would add some choice to the cabinet for the likes of deer sized animals.So going this route (if they reload), makes complete sense to me.

Now if the poster is looking for a new rifle that would serve the purpose of flat shooting for longer range 300 plusbut also lend itself to future large game hunts ie: elk or moose then I would suggest considering the 7mm STW. Again assuming they don't already own a capable large game rifle.

Of course it is possible the poster actually owns or has access to either one of these rifles which again changes the response IMO. If this is the case then I would suggest picking the one that is best suited for you personally. Factor in which rifle gives you the most confidence (ie: fits best, shoots best, etc) and which set up meets the expected requirement of the hunt. Then go hunting, cuz either one will get the job done on a Mulie!

So my advice is fill in some of the blanks andthen I know you'll get more to the point responses.

Best of Luck!!!!