Brass identification

[u/strickenchips]

So, I have 101 pieces of this stuff. I got it in an assortment of brass. It was advertised as "6x60". Everything I can see leads me to believe it is 6mm Lee Navy. However, as far as I know, Lake City never made 6mm Lee Navy brass. There are definitely swaging marks on most of the brass, rings at a couple of points along the case body and even some lines along the length of the case body. The neck has some minor vertical wrinkles, presumably from pushing back the shoulder and substantially necking down from a bigger neck ID.

Now, the headstamp on every piece is "LC 62 MATCH". Everything I can see indicates that it either has to be made from .30-06 or 7.62x51, but can you really swage and turn down brass this much? This, apparently, isn't even a popular recipe for making 6mm LN, the popular ones being .220 Swift and .30-40 Krag. Any ideas as to what I'm working with here? I don't have any LC .30-06, so I have a piece of 7.62N to compare headstamps with.

I'm sorry if my little chart down here doesn't format properly for desktop lol

Lee Navy? .30-06

Base .436" .467"

Rim .442" .467"

Case length 2.353" 2.489"

Mouth OD .271" .341"

ID .240" .308"

Base-shoulder 1.735" 1.952"

[u/moonpie_888]

.30-06 LAKE CITY 1962 MANUFACTURE MUST BE LEE NAVY