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All black "aym" round? What are they? on sks strip

1K views 9 replies 10 participants last post by  racefiets 
#1 ·
A friend of mine has some ammo that came in boxes on SKS strippers. We don't know if these are proof rounds or AP or what.

Info and photos reposted here with his permission and hosting:

Several months ago 80 rounds of rather evil looking surplus 7.62x39 fell into my lap. I brought these bullets up on TFR once before and after a brief discussion with B4tcom and Google we came to the conclusion that the ammunition is Czech in origin, and has a high probability of being high pressure factory proof loads designed to prove a that weapon was safe enough to withstand extremely high chamber pressures.

This past Friday I finally got some time in the shop to sit down and properly document one cartridge of the evil black bullets.

comparison flanked by wolf and winchester


closeup


headstamp


specifics:
Overall Weight: 248.7 Grains
Overall Length: 2.189" (inches)
Case Head Markings: "69 aym"
Notes: Steel cased, full steel jacket, Grey polymer/lacquer coating over entire cartridge.

close up of projectile:




Notes: Notice the presence of rust on both the cartridge jacket and core. There was similar rust inside of the casing itself that I neglected to photograph.




-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

I performed a cutaway on the "aym" bullet, you'll notice that the projectile is a two piece cartridge that consists of a mild steel jacket and a mild steel core. The hardness of the two components was the same, and the shavings of both components were magnetic. Surrounding the core is a medium of a softer silver colored metal that I believe is a tin or lead brazing compound because of its relative softness compared to the core and the jacket.



At this point I'm at a loss as to what the purpose of the bullet is. The powder type and weight leads me to believe that this is a standard pressure load but the steel jacketed projectile confuses me. While I was making the cutaway I was expecting to hit a hardened tungsten core which would have indicated the bullet was armor piercing but the core proved to be just as mild as the jacket which would limit the round's ability to penetrate hardened steel armor. Ive begun to speculate that this round is nothing more than attempt to make 7.62x39 less expensive to produce.

If anybody has any other suggestions to help determine the purpose of this ammunition please speak up because short of preforming performance tests on the cartridges I'm at a loss what to do with these rounds.
Mild steel, not tungsten. Were there ever real hardened tungsten steel cored, "real" AP 7.62x39?

Very interesting indeed.
 
#3 ·
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