A bloke gave me some old .22 rimfires, unfortunately loose with no carton, and when I measured it against a Federal .22 there were some differences....Federal case dia. .222, rim .270 case length .595.......Oddbod case dia. .247, rim .304 case length .657....any ideas ?? ( measurements are only rough )

Roger

Measure the bullet diameter, as those numbers are closer the the rim/base diameters for a 25cal RF.

.....I've destroyed two projectiles while unsuccessfully trying to remove them, but the best measurement I can get, at the end of the case is .215 or 5.5mm ??

Roger

Rimfires are normally a heeled bullet (major dia sits outside the case), and the case/bullet diameter are normally within a couple thou of each other.
As a guess, however, I'm going with the 22 Winchester Automatic.
Bullet dia, case length, OAL, Rim and Base dia (taken from 2 samples)
0.222 0.664 0.910 0.311 0.249
0.220 0.662 0.897 0.312 0.247

Hopefully "ZW" or "Muzza" will look at this thread, as their knowledge is greater than mine.

Tailgunner I am not home at the moment where i can check the dimensions to be sure but I believe your answer to the question is correct.
Zw