Czech Out This Czech Steel Jacketed Steel Core 7.62×39 [230Grain.com Repost]
Yet another repost from 230Grain.com
Some time ago I received 80 rounds of some very mean looking surplus 7.62×39 in light blue cardboard boxes. After some digging around on the internet and a brief discussion with some friends from The Firing Range we figured out that the ammunition was Czech in origin and potentially over or undercharged (factory proof or rifling test loads). Some more deliberation made me decide that it was my duty as a denizen of several Internet firearms communities to dissect and weigh a sample projectile and post the results on the Internet. The results have been been on 230Grain.com and on the Something Awful but I figured it was deserving of a slightly more permanent article here.
Section 1: Initial Cartridge Appearance and Measurements
Wolf 7.62×39 FMJ, Copper Jacket, Steel Cased, Polymer Coated
Wolf Cartridge Overall Weight: 251.3 Grains Overall Length: 2.184" (inches) Case Head Markings: "7.62x39 WOLF" Notes: Steel cased, full copper jacket, Grey polymer coating on case.
Winchester 7.62×39 FMJ, Copper Jacket, Brass Case, No Coating
Winchester Cartridge Overall Weight: 275.1 Grains Overall Length: 2.164" (inches) Case Head Markings: "7.62x39 WINCHESTER" Notes: Brass Cased, full copper jacket, no coating
“aym” 7.62×39 FMJ Steel Case, Steel Jacket, Polymer Coating
Wolf Cartridge Overall Weight: 248.7 Grains Overall Length: 2.189" (inches) Case Head Markings: "69 aym" Notes: Steel cased, full steel jacket, Grey polymer coating over case and bullet
Section 2: Pulled Component Measurements
Wolf 7.62×39 FMJ, Copper Jacket, Steel Case, Polymer Coating
Wolf Measurements -Bullet Notes- Type: FMJ Boat Tail Jacket Material: Copper Core Material: Lead Length: 1.048" Width: .310" Weight: 122.8 Grains -Case Measurements- Type: Steel Case, Polymer/Lacquer Coating, Crimped Length: 1.520" -Powder Measurements- Type: Extruded Powder Weight: 23.7
Winchester 7.62×39 FMJ, Copper Jacket, Brass Case, No Coating
Winchester Components -Bullet Measurements- Type: FMJ Spitzer Jacket Material: Copper Core Material: Lead Length: .846" Width: .310" Weight: 121.7 Grains -Case Measurements- Type: Brass, Crimped Length: 1.523" -Powder Measurements- Type: Ball Powder Weight: 22.9
“aym” 7.62×39 FMJ, Steel Jacket, Steel Case, Polymer Coatin
"aym" Components -Bullet Measurements- Type: FMJ Boat Tail Jacket Material: Mild Steel Core Material: Mild Steel Length: 1.046" Width: .310" -Case Measurements- Type: Steel Case, Polymer/Lacquer Coating, Crimped. Length: 1.521" -Powder Notes- Type: Extruded Powder Weight: 23.0 Grains
Note: I negleted to photograph the rust on the inside of the cartridge, but the level of oxidization on the interior of the casing as there is on the base of the projectile. It would appear that there was no form of pasivation on the interor of the cartridge and that the polymer coating was applied after the cartridge was assembled.
“aym ” Cutaway
In this photograph notice that the projectile is a two piece bullet consisting of a mild steel jacket and a mild steel core. By performing a simple scratch test I was able to determine that the hardness of the core and jacket was similar. The shavings of both components were magnetic indiciating that it is ferrous innature and between the core is a medium of a very soft silver toned metal that appears to be tin or lead brazing used to bond the jacket to the core.
After further discussion on a seperate forum, it would seem that these rounds were produced this way simply because of a copper shortage in the Czech Republic during that time frame, and that it is standard ammunition. It was also mentioned that this style of ammunition was banned at one point in time because the ATF considered this to be armor penetrating pistol ammunition because someone once made a pistol that shot 7.62×39.