Unusual US .50 browning dummy

I had never seen this kind of dummy,
There are 2 holes of a 2,5 mm diameter on one side of the cartridge. There is an internal spacer in the case, the bullet is unmagnetic and the base was striated before the headstamp had been done. Total weight is 91 grams.
Is this a common kind of dummy?

Looks like it is ready to screw to a board, But I’m not 100% sure with the screw hole at the neck. Although I do have a WRA with a screw at the neck but it has two holes in the body.

No not common.

Thanks, I hadn’t though it could be for a board.

I have a whole series of dummies that are prepared just like that to screw to a board.

The circular patterns on the head though…


My U. S. Navy cartridge board from 1944 has all of these mounted thereon…….One screw into the head area and one in the neck……….apologies for the fuzzy photo. All are headstamped F A 4 or F A 44. Many have lathe marks on the heads exactly as in laurent’s picture. They are in the middle vertical column.

Randy is correct, I believe. There were a fair number of these boards made, but at about 30" x 60" they are awfully heavy and bulky and many have been broken up over the years, or suffered damage so that some of the cartridges may be found loose now.

Thank you all for this quick identification, so Pete was on the right way!