Pronghorn antelope are relatively small, thin skinned animals. A high velocity bullet, like from a 7 mm Rem mag, through the shoulders or hams of an antelope, deer, or even an elk will ruin a lot of meat. Put that same bullet tight behind the animal's shoulders and through his lungs and you will have a quick kill with very little meat damage.
I've only had a 7 mm Rem mag for a little less than 20 years. I consider the 7 mm Rem mag one of the best all around cartridges for North American big game animals. My favorite bullet for mine is the 160 grain Accubond. I've used a 7 mm RM for deer, antelope, elk, caribou, muskox, and saw it used on a one shot kill of one of the largest moose ever killed in Montana. I've had two 7 mm Rem mag rifles, and also used them on two African hunts for a variety of antelope from bushbuck to Kudu.
As others have posted, you don't need the power of a 7 mm RM for pronghorns, but it has good long range ballistics, and IMO it doesn't have excessive recoil.