I've had mixed results with MagPro. Tried it after a buddy of mine said it worked well in his .300 WSM. Couldn't get it to shoot well in my Kimber 300 WSM. Tried180 gr Interbond's and 180 gr. Partition's and just couldn't get it to group worth a darn.
Since I had some MagPro left over I loaded some rounds for a friend's 300 WSM and had it shooting sub MOA with the 180 gr. Interbonds. To reach the max loads in reloading books it filled the case and was a heavily compressed load IMO... perhaps the bigger case would alleviate this.It does meter very consistently in my experience though.