fmj vs. steel core, steel jacketed ammo

[laserfaith]

Hi friends,
My shooting ranges doesn't allow steel core, steel jacketed ammo. What the difference between those kinds of ammo and fmj? Are some fmj steel jacketed ammo? Thanks,
TT

[Agent Ronin]

Ahh you asked a mouthful there... Let me attempt to clear this all up.

Core material, this is easy, its either Lead (good) or mild steel (typical of eastern bloc surplus ammo) and lastly hardened steel (armor piercing).

Now for the jacket, FMJ is just the type of bullet as for what its made of is what the range is looking for. There are a few types.
-Copper Jacket, all domestic ammo should be full copper jacket.
-GMCS Jacket (Gilding Metal Copper Steel) is typical of US Military ammunition, its a copper alloy that has a small amount of steel in it.
- Bi-Metal Jacket, this is the one you want to avoid at your range. Alot of imported ammo makes use of the bi-metal jacket, which is nothing more than a steel jacket that has been copper plated. Wolf, Sellier & Bellot, Barnaul, and a few others are all bi-metal ammo.

Typically boxed ammo is marked whether or not its a bi-metal or copper jacket, GMCS jackets are harder to detect without the aid of a magnet. And one last bit, if its got a steel case, assume its a bi-metal bullet.