Originally Posted by
zardoz
I have assembled my own 300AAC Blackout, and 458 SOCOM rifles. Both were attractive to me, because all my standard AR magazines work without modification. I can swap uppers and lowers between the three platforms as well. So I can mix and match magazines with varying capacities between my 5.56 AR's, and the two larger calibers.
I like to use the 20 round magazine on the bench, because it is less awkward than the 30 rounders. The 20 round standard AR magazine will hold 7 rounds of 458 SOCOM.
I can use the same boolits, or j-words between 308 Win, 300 Win Mag, and the 300 AAC. Then, boolits and j-words made for my 45-70 Marlin work in the SOCOM. I have a nice Ranch Dog 350 grain .458 mold that works very nicely in the SOCOM. My main thing was interchangeability.
Brass for the SOCOM is fairly expensive, but I suspect the same applies to the other large caliber AR brass.
That's just my preference, having looked at both the 450 Bushmaster and 50 Beowulf a lot before finally deciding on the SOCOM.