von luckner

Patently incorrect 5.56x45 has exceptional terminal ballistics considering the size- because of the high muzzle velocity and specific bullet design, rounds not only tumble, but also fragment leaving a large permanent cavity (there are some extremely graphic pictures of 55gr. ball wounds out that will quite adequately illustrate how deadly 5.56x45 is). By contrast, most other FMJ rounds, such as 5.45x39, 7.62x39, or 7.62x51 only tumble. The mechanism of injury with these other rounds is predominantly a temporary cavity caused by the shock of the bullet passing through a largely liquid medium. For rounds as powerful as 7.62x51 this is substantial, and can cause significant damage to vital organs, but for less powerful, steel-jacketed Russian ammo, such as M43 or M74, the results can be much less impressive. It is not unheard of for 7.62x39 to pass clean through without much secondary damage at all. The controversy surrounding 5.56x45 results from the accurate reports that out of a carbine-length barrel (M4 variants), muzzle velocity drops off too quickly, and as a result M855 ball ammunition will not fragment reliably beyond 100m. This has been especially important in some of the regions of Afghanistan. The reason the controversy is so senseless is because all it means is that the 5.56x45 is vastly more effective at close ranged (<300-100m) than all other intermediate service cartridges in general use today (meaning 5.45x39, 7.62x39, and probably at least comparable to 5.8x42), and just "on par" beyond that. I will add that replacing 5.56x45 with 6.8 SPC has never been on the table, all indications are that not even special forces units have considered adopting these new 'boutique' calibers (niether the HK416/417, nor the SCAR platform are available in any non-nato caliber)- this is purely, and I mean PURELY a product of gun rags trying to sell new AR-15 components. US forces have reacted to the controversy surrounding the 5.56x45 in two major ways- first by supplementing normal infantry units with increased usage of designated marksmen equipped with modernized M14s, and second by developing and adopting the M855A1 and 77 gr. Mk. 262 cartridges, both of which offer much better performance at range than the standard M855 ball. Please note the fragments of lead and copper jacket.