ANM-57A1 manufacturer stamp

[DEADLINE222]

I know this is a long shot, but I am hoping to get lucky. I recently acquired an ANM-57A1 casing made in 1945. Before the lot number there is a stamping which I have provided an image of. There were several manufacturers who's name started with "N", but little to no information is available to any of the manufacturers but National Tube or what it was know as in the time period; Christy Park Works. I have an image of the casings being produced, and they identical to my casing. (There are several variations of casings I have seen, different styles of suspensions lugs and so on.) Furthermore, according to my research; Christy park was the only manufacturer who used metal spinning to produce casings rather than the industry standard of piercing and draw. Is there any way to determine if this method was utilized to produce my casing? Any help will be greatly appreciated.

 

[HAZORD]

Spinning would leave a smooth outer surface without longitudinal lines, whereas if it is drawn or ironed, you will usually find longitudinal lines like stretch marks, especially where the body diameter necks down on the rear for the base plug.

Spinning might also leave very small marks around the bomb body and leave a much nicer finish. Usually the ogives are fairly rough on the drawn/forged ones, as the pressure to form the hot metal didn't remove the rough surface. The spinning makes a highly concentrated pressure at the point of contact, which would burnish and give a finishing effect to the surface.