I bought a single shot AR-15 upper several years back and had fun with it just for throwing API and APIT out in the desert where there was nothing to burn down. Lots of wide open spaces with no civilization to worry about ricochets.
Even so, it got old. Once the initial fun wears off, it's a 20-35lb rifle that costs $3-10 a shot to fire, it kicks the shit out of you (just the blast is enough to ring your bell and fuck with your sinuses), you need a designated spotter, it's hard to load develop (money, recoil, flinch, limited component selection), and all my attempts at accuracy left me kind of "mehhh". Lots of real ranges won't allow them. So I sold it.
For the longest time I was of the opinion that it was just the AR-15 setup that was what made it less bearable and that a purpose built rifle would be the way to go. I set my sights on an AW50 and put it in the "one day" category. Earlier this year I got the opportunity to mess around with an AX50 and thought "Oh cool!" until I started handling the rifle...
It's heavy. It's heavy. It's stupid. The same problems persist on the recoil, blast, and financial side of things which in turn limits accuracy/precision potential, which in turn limits maximum effective ranges, which begs the question why do I want this big heavy piece? The only benefit over something like a .300 PRC, .300 Norma, .338... is energy on target. How much energy do you need on target? Which also begs the question of available range space, backstops, ricochet hazards, etc... You're starting to throw some serious heat down range, and in the case of AP, API, APIT, there's a pretty serious core inside that doesn't deform, splatter, etc. like a lead core does. Same story for the turned solids. It's going to leave a mark on whatever it hits, even from a ricochet.
If ELR (past 2000yd) is the goal, then the .416 and ESPECIALLY .375 options piss pound the .50.
Just food for thought. It's all expensive and the more you shoot the less you want to. It's approaching the size that the gun ought to be on a carriage with a T&E.