In my copy of Pistols of the World, Ivan Hogg and John Weeks, 1978 shows a picture of the "Fiel" that Bill suggests. In the text it says, " It was followed, probably at the end of the war, by a 6.35mm model based on the Browning 1906, but without grip safety, and with the rear of the slide rounded off. This was marked 'Automatic Pistol 6.35 Fiel No. 1': it carried no maker's name, and the black plastic grips had a plain oval thumb grip at the top." The configuration of the pistol in the books picture is exactly like yours save that it has a few more gripping slots in the slide. It also has the small D in the same place on the left side of the slide. In the back of this same book they have an Index/Data Table that gives a Fiel #1 in 7.65mm that is 148mm long that weighs 597 gm with an 84mm barrel and has a seven round magazine. I think Bill nailed it. Regards Tom