7.62 X 54R Polish Dummy?

This must be a Drill/Dummy of some type, it has a Steel case with Copper wash and 4 short flutes the headstamp is 21 76 the 76 is inverted, the bullet and primer appear to be made of White Plastic, can someone please help with correct ID and who used this type of round, this is the first one I have seen even thou its been around since 1976, thanks Randy

Randy, this is a typical Polish dummy as it exists in other calibers as well. The white plastic is cast into the case and filling it completely and forming the projectile section.

These were scarce before but in recent times plenty of these have been surplussed it seems and they became available by the box.

Alex, were they ever made in 7.62x25?

Jon, I have never seen such ones in 7.62 TT (to my regret). The earlier Polish dummies were made in a more traditional way (regular fluted case + regular projectile) and only later on the plastic injceted dummies were made. So I guess the plastic type came out after the 7.62 TT was out of production already.
It would be interesting to hear from people here about head stamps on the earliest plastic types.
What is the latest known Polish 7.62 TT head stamp?

Earliest I know of are:
9x18: 21 75
7.62x54R: 21 75
The latest I know of is:
7.62x39: 21 92

Calibers made this way as a dummy I have seen so far:

Can anybody contribute earlier or later dates or other calibers?

Has anybody any info as on how the dummies for the Polish made NATO calibers do look like?

The latest Polish Tokarev ball headstamps are 54 56 and 343 56, and the latest blank (probably for movie use) is 21 90.

OK Alex, thanks for your reply. Randy

To support EOD: The earliest Polish plastic injected dummy I know of is dated 1975.