in 1983, Research Armament Industries (RAI) in the United States began development of a new, long-range sniper cartridge capable of firing a 16.2-gram (250 gr), 0.338-inch (8.6 mm) diameter bullet at 914 meters per second (3,000 ft/s), that could lethally penetrate five layers of military body armor at 1,000 m (1,094 yd). After preliminary experiments, they came up with a .416 Rigby that was necked down to a .338.
Now Lapua went to design the "BRASS" for this Cartridge.
Lapua opted to redesign the .338/416 cartridge. In the new case design, particular attention was directed toward thickening and metallurgically strengthening the case's web and sidewall immediately forward of the web.
The BRASS that you have may be from the first production of the .338LM. At that time since it was to be specifically used as a "Sniper Cartridge" they did not put markings on the "Head Stamp". There were about 250,000 Cases made at that time.
You don't see Brass without any markings.
Cartridge/Case Head Stamp Guide
en.wikipedia.org
Really interested in:
Question to you is - How did you know it was .338LM Brass, where did you get this brass from, how long have you had it and have you ever checked it (compared) to other .338LM brass "Brands/manufactures" as far as the weight, wall thickness, neck thickness.
We have gauges to check out the brass diameter-thickness. If you have a NECO Concentricity Gauge you can check for yourself and a good weight scale. Then compare to a Lapua and other manufactured cases.
As far as pricing, that is your decision. I know what I can pay for new .338LM Brass.