I don't know if I ever posted any comparisons between the three big bores......probably not.
The bottom line is that all three will get the job done.
The Beowulf of course has a larger diameter bullet, but with that comes less sectional density (the bullet is short and fat) so your penetration capability will be less than that of the smaller diameter .458 SOCOM running a longer bullet. Back in 2001 there weren't many 50 caliber bullets to choose from (50AE only) but now with the 500 S&W there is a better selection so the bullet availability argument is pretty much a thing of the past.
The Beuwolf also suffers from a severely rebated rim that can cause some problems. One is bolt over ride, whereas the bolt misses the rim of the cartridge when using some magazines. The other is a complete case collapse around the case head when the pressure is driven up. If you run the pressure up, the case will fold back over the case head. The same problem occurs with the 501 Thunder Sabre case. Neither of these issues show up with the SOCOM. The other problem is the Beuwolf's nose will strike the front leading edge of the GI magazine when feeding out and again does not present a problem with the SOCOM's bottle neck case.
The Bushmaster is really not a great idea in the AR, since the case diameter is smaller, it doesn't want to feed well, single stacked in a GI magazine. You have two choices when feeding through a magazine. You can either single stack them or you can double stack them. You can't stack-and-a-half them.......very well. Also, pushing pistol bullets to rifle velocity usually does not work very well either. You would really need to shoot specially built .451" rifle bullets for best performance. Of which there are very few of.
When Marty ter Weeme and I were first discussing the big bore project, we were discussing simply using a lengthened 50AE case necked to .458. We considered using both the 7.62x39 rim and the .308 size rim, but went with the .308 to prevent possible bolt over ride issues, case collapse issues, and allow it to be easily adapted to bolt action rifles. All of the initial cases that came from Starline were straight walled, so we already had a 50 SOCOM if you will. I considered getting a reamer made for the 50, but the .458 just seemed like a lot better idea, so the 50 version was scrapped. I still have several thousand 50 SOCOM cases left over, so it could still be done without much trouble.
Bottom line though.....if you use the right bullets, magazines, and keep the pressures sane, you won't have any problems with either of the three rounds. In my opinion (whatever that is worth) the .458 SOCOM is "Technically" the best design of the three, but in actual application, they are all about the same.
Tony Rumore
Tromix Corp