I had posted a  message a few months back about problems with the 458 socom but never followed up (I have been sick). Just want to let those who may remember know not only is the 16" carbine working great now but I also built a 10.5 pistol in 458. I. I can now shoot through cinderblock  walls. My main problem with that round, and the 458 socom ammo in general is that its too damn expensive..

I did the following to get the 16 inch carnie going
1)..Installed a TROMIX ejector pin. Used sandpaper and elbow grease to thin the walls on the bolt (make the face opening wider.
2). Drilled the gas gas port out to .0125 (1/8 inch)
3). made a new barrel extension and installed and correctly headspaced it.
4). Bought a Wilson combat .458 SOCOM stripped upper and installed it.
5). Bought some Wilson combat 458 mags
5). Pulled the bullets from my commercial ammo then resized the cases and reloaded the bullets.
6).Nnew buffer spring and H2 buffer
7). Eotech with 3x flip up magnifier.
Works great now

For the pistol I built it as follows
1). Tromix 10.5 inch barrel and bolt
2). Satern (no, its not Saturn) big bore billet upper
3).  Spikes stripped forged lower -
4).  Phase 5 buffer tube, buffer and spring
5). YHM 7-inch quadrail
6).  Troy min battlesights
7)   Cheap Walmart laser sight (works great)
8)   Wilson flash suppressor.
This gun has worked perfectly from the get go.

I still admit that I wonder if the 458 SOCOM will fade away. I say this mainly because:
1).  Lack of SAAMI spec
2).  Ridiculously expensive extremely hard to find ammo
3).  Narrow selection of bullets for reloading..
4).  This is not a new round. It has been around for about 15 years. The mere fact that it hasn't taken off yet concerns me.
5).   Put those shells in Walmart!

There is a great selection of 458 bullets thanks to the 45-70 and 458 win mag and Lott. I hope it doesn't fade away since I need more brass but I doubt it will ever be in Walmart either

I'm in the process of getting everything together for my first .458 build.  Got Tromix barrel and bolt on the way now.  As far as bullet selections, there are quite a few choices available.  And as far as ammo goes, reloading is about the only way to run these things.  Only other big bore that is cheaper to shoot factory is the 450 bushmaster, brass is cheaper but bullet selection is far less than the Socom.  Couple years ago I had a 50 Beowulf and brass was easier to find.  I thought about getting into the Beowulf again but can't find ANY brass for it.

I don't think it will ever fade away, it's just that the big bore AR's are a niche market, besides the 450 bushmaster I don't think ammo will ever be readily available anytime soon.

Yes, reliable reloading data is scarce. If nyou do searches you get the usual internet mind numbing drivel. I have loaded he Hornady 325 FTX with 34 grains Reloader 7 and it shot well and I didn't get blown up. I get a decent grouping at 100 yards. I have also loade the Barnes 250 gr flat nose hollow point at 36 grof 4227 and the Barnes 350 grain at 34 grains 4227. they all shoot and I am still here and not blind but beyond that I admit to being very much an amateur at .458 socom loads. I have barnes 300 gr. TSX flat base bullets (not the one designed for SOCOM) and would like to find a good load for that. Just as a swag I am thinking I will load a few with 33 grains X-terminator and see how they shoot. Don't have a chrony. Good luck with your SOCOM.