This post is in reply to the 458 SOCOM bullet pictures, and I thought I would share a few facts and opinions just to inform you of what's out there and things you might want to know. Right after the Blackhawk down incident in Somalia, a guy named Marty Ter Weem saw a need for a large caliber AR platform for the purpose of blowing door hinges and also heathen infidels out of the way, and set out to make the biggest caliber AR upper he could that would still use regular .223 mags and uppers. What he wound up with was the 458 SOCOM, which has a 50 caliber case body, a 45 caliber case neck, and a 30-06 rebated case head. It's an incredibly versatile round, and you can run anything from a 250 grain .458" rifle bullet to one of the big Barnes 500 grain solids through this thing. From what I know, the DoD has been buying Marty's stuff since he started building it.http://www.sbrammunition.com/458sl.html http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=251
Now then, at the beginning, Marty had a gifted but fully gonzo gunsmith name Tony Rumore (Tromix.com) who was building the 458 SOCOM uppers, and Tony was also offering uppers that whould shoot the 50 Action Express cartridge. The 50AE, by the way, is a 50 caliber straight walled case with a 44 magnum rebated case head. That combination was selected so you could upgrade the 44 magnum Desert Eagle to 50 caliber without changing the bolt face or slide. Seeing as I had a DE 50, I went ahead and bought one of Tony's Sledgehammer AR uppers in 50AE, so I would have a pistol and AR combination that would shoot the exact same round. It should be noted that to make a 50 AE upper, Tony had to machine out the AR bolt to tale the larger case head, build his own extractor hooks, and open up the gas port to make the system work. Seeing as the 50 AE round is shorter than the .223 round by about half an inch, Tony put Delrin spaces in the front of his .223 mags to keeps the rounds where they belonged.
Now, in a galaxy far, far away, there were two guys who also wanted to make a 50 caliber AR upper, but they wanted to use all stock AR components and not modify the mags, so they designed a case unlike anything that had ever been seen. The case body is the same diameter and length as the mighty Smith 500 so it would fill up the mag, and then they put the case head of the 7.62 x39 AK-47 round on this massive case, because they wanted to use stock AK-47 bolt faces, which ARE available for AR-15 uppers. The result is grotesque beyond all imagining, and here are a couple of pictures of what was created.
And just for reference, here's the 50AE, the 50 Beowulf, and the 500 Smith.
Now, the 50AE cartridge is a time tested and proven round. There have been many guns chambered for this round besides the Desert Eagle, and this round IS a military round in the Isralei Army. (Glad I'm not a Muslim terrorist!!
The 500 Smith is a MUCH more powerful round than the 50AE, and was also well designed, and has a pressure rating of 65,000 CUP. In general, your wrist(s) will give out before a Smith 500 will, especially if you are shooting those humongous 440 or 500 grain bullet rounds.
Shortly after this round was created, its two designers got in a huge pissing match and split up. As such, there were two different headstamps for the same case, with one being the .499 Leitner-Wise, and the other being the 50 Beowulf. The .499 died on the vine, but the 50 Beo lived on and was offered to the US Coast Guard for trials.
Now then, a little math and geometry is in order. For the 50AE cartridge, the minimum diameter of the case head (meaning extractor groove) is 75% of the cross sectional area of the case body. For the tiny 50 Beo case head, the cross sectional are of the extractor groove is only 48% of the area of the case body. That's the math. Now for the geometry, look at the difference between the body tapers between the 50AE and the 50 Beo:
The taper angle is much steeper for the 50AE than the 50 Beo, which means that the pressure from the case body can more efficiently and safely be transferred back to the case head, and there's never been an incident I have heard of where 50AE brass blew out or collapsed.
When you add up the less-than half the case body area to case headwith that shallow base taper, things are entirely different. Second hand, I have heard reports of full case head collapses into the case body, and also stories of the bolts on some guns getting blown. The initial loadings may have been hotter to try and use all that case capacity, but with that case design that didn't turn out to be feasible. Last I heard, the 50 Beowulf round hrows a 325 grain bullet at about 2100 FPS, while my puny little 50AE Sledgehammer puts the same bullet out the barrel at 1800+ FPS with stock Desert Eagle loads. Needless, to say, that's WAAAAYYYY below what you could do with one of the rifles currently chambered for the Smith 500. (Hell, I can get a 325 grain bullet to 2000 FPS with my 8 3/8" barreled pistol!)
So, if you're looking for a large caliber AR upper, you can look at the 458 SOCOM, and if you don't reload you can pay for your reloading setup in about THREE boxes of 458 ammo! The other round to look at is the 450 Bushmaster, which was developed by Hornady and Bushmaster, and is probably a slightly depowered 460 rimless Smith round.http://www.ableammo.com/catalog/default.php?cPath=10480_14658_14743_14909_16855