Ive only messed with, and helped a friend tune his 458 once, but some limited info I can give that I have gathered are.
I had it at my place for about a month tuning, upgrading, and modifying.
the 458 is almost equivalent to a 45/70 ballistically, and kicks a little more than a 30-30, not bad at all.. (not that bad at all for a day at the range, but Ive only ran around 100 rounds while tuning it up.)
16" barrels seem to be the preferred barrel length.
its like shooting a 45 into a target, most say it only will penetrate about 8 inches into hogs, but it packs alot of energy, at 1600+/- FPS
(its basically a 45 acp bullet going really really fast.)
I've never shot a 50 beowolf, but from friends that have, they say it kicks like a mule. and most of those guys only shoot it to show off, and to be able to say they have a "badder AR" than the next guy...
and reloading is pretty much a must, if you're lucky enough to actually find ammo, be ready for sticker shock!
Im in Arizona, the most gun friendly state, and he has only found one box on the shelf anywhere, he has been loading all of his own ammo.
I own 2 458 SOCOMS. A 16" RRA and a 10.5" Tromix pistol. I have fired the 16" a lot. Probably close to 1k worth. The pistol I have only fired once for a function test. I bought the 458 because of the benefits found in compatability with the ar15 lower. No need to make modifications at all. Also it headpsaces off the neck rather than the case rim as the 450 and Beo do. You are shooting a .458" dia bullet and it moves along like a freight train. I found on Wiki that the 458 holds a slight advantage over the Beo in the energy area. Still they both pack a punch. Here is a shot of my 16 and the pistol in progress.
And the finished pistol
They are both a blast to shoot. I will be getting an SBR for the pistol and a can is in the works.
Yea the 45 raptor looks like a pretty nice platform. However it is on the AR10 style frame. One of the big reasons I got rid of my ar10's was the weight. If I were to go to the AR10 frame it opens up a whole new world of calibers. 300wm, 7mm08, and many others.
My 458 pistol weighs less than 5lbs and is really easy to pack. I have not had a chance to take it to the range yet but hope to soon. I chose the Socom as it gives me the best of both worlds. Hard hitting rifle in a smaller package (which is the reason it was developed). Not to mention the compatibility within the ar15 platform.
The beauty of the 458 SOCOM is the wide selection of .458 bullets, and their known performance on game in the .45-70 (which has velocities comparable to the SOCOM). There's no guessing which bullet is best suited for a particular task, as there is performance information readily available on the 'net. The MarlinOwners forum can be a very valuable resource to a SOCOM shooter.
Well, took my baby out yesterday. Put 40 rounds through her, 20 300gn JHP and 20 325gn FTX. All fired with zero failures. With the 4moa red dot it was hard to get scope accuracy. I was keeping them in the 9 ring at 50yds. If I decide to really put her through her paces I will put a higher power scope on. Also once I get the SBR I can put a real stock on. This will help a lot. She did punch a bit more than her big brother but that was to be expected. She is a really nice addition to the group. I cannot recommend this platform enough. Tromix did a great job with their contributions to the build.
I don't have any data at the moment. As far as signing up on 458 forum, need to email Tony the admin. He will manually set up your account. They had too many spam bots. Also you can peruse the forum without signing up. When I get a chance I will run varget on quickload for you.