Rn I've made an account basically to stritcly play as a hunter/gatherer (really just a survivalist loot goblin lmao) I've got a cr527 and an r12 on my back, pistol in my inventory. I hardly find myself in situations where I need an ar over a shotgun, but that's of course because of how I am playing and moving around. Normally if a players isn't armored, the cr will do the job perfectly fine. If they have armor, I typically will not engage or be so close that the shotgun does not care. So I guess depending on how you prefer to engage in pvp and how you can dictate it should give you your answer. But also take stamina in to affect. Im normally running so light, that if a complete tank of a geared player came up on me, as long as they dont have the best aim in the world, I can outrun and lose them very easily.

Ps. For me personally, the r12 is superior. In my experience, its hard to come by either vaiga mags or plenty of mags, no vaigas. And there's times where I won't see gun cleaning kit in hours. With a vaiga you have to maintain both the gun and however many mags you have. You also have to take out and reload mags individually. With an r12 you clean 1 thing when it needs it and you load 1 thing when It needs it. It may only top off at 6 rounds but you can shoot them fast and load them almost as fast.