.458 Socom is a fairly new rifle caliber developed in 2000 AD that is specific for a customized upper half of an AR-15 (which is a semi-automatic civillian version of the fully automatic M16).
(AR15 Image Property of Bushmaster)
The AR-15 is probably the most versatile rifle on the market. By simply pushing out two push pins, and in some cases replacing the magazine, the upper receiver can be replaced with an upper of different caliber converting the typical .223 rifle into one of many calibers. Conversions are possible in the following calibers:
'Socom' is short for 'Special Operations Command'. Not only is the .458 Socom great for military special operations that require a more potent caliber, it also opens up the AR-15 platform for big game hunting in the US. The great thing about the .458 Socom is that you can use the AR-15 platform, giving you a light weight potent rifle that is durable and lightweight, especially suited for big game hunting even in remote mountain terrain. Unlike the high velocity smaller diameter bullets, the .458 does not destroy edible meat on smaller game such as deer because of it's low velocity. It's a very good caliber for hunting big game in brush or timber where the range is fairly short. It's potent enough to take all big game in North America including the great bears.
(AR15 Image Property of Wikipedia.org)
.458 Socom is especially suited for handloading / reloading which increases its versitility and decreases the cost of ammunition. It uses a .458 inch diameter bullet, the same bullet diameter as the 45-70 military / hunting cartridge but able to withstand a higher load. Keep in mind that the 45-70 (designed in 1873) was used for buffalo hunts in the old west! The .458 Socom bullet weights range from 250 - 600 grains, with velocities from 980 feet per second (subsonic) to over 2000 feet per second! The effective range is similar to the 45-70. Using the 405 grain bullet it is accurate on a man size target to 300 yards, a 6 foot by 6 foot target to 600 yards, and with a 500 grain bullet can produce lethal injuries at 3,500 yards (almost two miles!). The bullet has a rainbow trajectory so unless you are skilled and know the distance, your bullet weight and powder, and correct for bullet drop, the effective range is about 100 yards. Of course with a lighter bullet and higher velocity the amount of bullet drop decreases. Here are a few reloading stats:
(Image Property of Rock River Arms)