Had never seen or heard of the caliber before.
Copied and pasted off of this website.
You can throw rocks if you want, and probably know more about ballistics than I. But I posted this to show that the reported caliber with a 20 round clip could explain the high number of rounds he got off.
And depending on the bullets and his accuracy the high kill rate.
I do not know why everyone is so argumentative on this.
I guess it best that I leave it alone.
TF
5.7 facts, pay attention to the power paragraph below:
Cost - Entirely out of whack considering the actual production costs and materials used in the pistol. Dealers often sell the gun at a very nominal markup and it still seems vastly overpriced for what it is. FN easily trumps HK in the contest to overprice their product for the civilian market.
Accessories - The integration of a well designed Picatinny rail on the pistol opens up a lot of options in the long term. In the short term, there is not much available specifically for the gun. Owners must either be satisfied with general fit holsters or get them custom made.
Mags - Definitely a weak point in the system. Reliable and practical, but only available from one source. Some dealers and vendors are stocking up on mags for this pistol. Prices are on the high side of reasonable. We are stocking the mags at for immediate shipment.
Longevity and durability - Unknown at this time, but not promising for long term use considering the extensive use of plastics in the construction of the gun. Short term harsh environment longevity might actually be pretty good due to the lack of parts that are vulnerable to rust.
Ammunition - Difficult to obtain and expensive. The situation is unlikely to improve unless more manufacturers sell guns chambered for the 5.7 cartridge. Most ammunition for this pistol has become obscenely expensive on the open market.
Power - Questionable stopping power, but holds a lot of promise, especially as a midrange survival pistol. The power of the bullets fired from this pistol are roughly equal to .22 magnum fired from a long barreled rifle. The rare and costly hollow point bullets will even tumble when they hit a pop can, so there is some real potential for stopping power with this gun if the ammo supply gets sorted out right.
Parts - Spare parts for the gun are practically unavailable. Ergonomics and handling - Excellent, although the safety takes some getting used to. Extreme care must be exercised when handling this pistol because the safety can be inadvertently flicked on and off, even when inserting it in a holster.
Popularity - The 5-7 is not a popular gun and at current prices is not likely to ever become popular with the general public. It is likely to be well recognized due to the notoriety that some gun control groups are giving it and the guns have gained some interest with specialized law enforcement and security personnel. The price of the pistols and ammunition makes it unlikely that they will ever see common use by criminals as feared by some law enforcement and gun control groups.
Maintenance and repair - The clean burning powder and largely plastic construction makes this a particularly low maintenance pistol. The lack of any cost effective availability of spare parts can be cause for concern. Very few, if any gunsmiths who work in the private sector are schooled specialists in working on this pistol.
Accuracy - Seems good for man sized targets out to 50 meters, and probably 100 in the hands of a capable shooter. The gun is quite usable on small to medium game out to 50 meters. Reliability - The test specimen has been 100% reliable. We have not heard of any of these guns suffering from reliability problems.