I'd hold off on the Paramount until its on the market and guys are shooting them. Lots of gas leaking at the breech in their videos. Not sure how well a "self-headspacing" bolt is going to work, if at all.
Lots of guys like the 45 for shooting...lots more full size to choose from and if going with sabot even more....
Biggest negative....lots of states require 50 for elk.....
45 will do just as much damage as a 50....just another straw up someone's but a long time ago when most were shooting flintlocks....primitive weapon...just like a rock.........or a stick.......or the bottom of your foot.....