I'm now contemplating building an upper in this cartridge as well. From everything I've read, Tromix is really the best option in regard to barrels. Second to that would be RRA. I see Brownells offers a barrel in 458S, but so far no reviews on it. Once I pull the trigger on getting the barrel from Tromix, I'll start to piece together everything else. Reloading dies will likely be on my next Midway USA purchase as well.

I saw someone else had asked what optics people are running on their 458S rifles. I too am curious about that (excluding irons of course). I was thinking of going with a Vortex Spitfire 3x Prism with EBR reticle.

From all the research I've done, it looks like this cartridge really took off. This thing is gonna be a fun to sight in at BlueCore with a muzzle brake on it.