Modern firearms are typically described by their bore diameter (7.5mm) or calibre (.357) or gauge (12 ga.), the type of action employed (muzzle, breech, lever, bolt, pump, revolver, semi-automatic, or automatic) together with the usual means of deportment (hand-held or mechanical mounting). They may be further distinguished by reference to the type of barrel used (rifled) and the barrel length (19 inch), the design's primary intended target (anti-aircraft), or the commonly accepted name for a particular variation (Gatling gun).
The Firearm Puzzle HD is a collectiong of high quality gun pictures, the features is:
1) A variety of topics, contains "AK-47", "M82 Barrett rifle", "Browning Hi-Power", "M4 carbine", "M1911 pistol", "Revolver"
2) difficulty choose, from 2x2 to 11x11
3) Multitouch support, you can play with your friends or kids
4) weekly update