PS 75 headstamp .30-06


#1

Where do you suppose this brass came from? According to your ID page it has 4 sources.

Italy, Korea, Spain, Chech. I live in the USA.


#2

Can you post a photo ?

I’d go with Korea.


#3

Can’t post a Pic… it has a circular crimp.


#4

milboltnut–With a 1975 date it is almost certainly Poong San, South Korea.


#5

[quote=“milboltnut”]Where do you suppose this brass came from? According to your ID page it has 4 sources.

Italy, Korea, Spain, Chech. I live in the USA.[/quote]

The factory Pirotecnia Militar de Sevilla was closed in 1966. Its headstamps were PS, PMS and PM.


#6

I did a google search and found Korean to come up time and time again. I also found one link about problems of splits along the base of the casing.


#7

Some of the many lots of Korean surplus .30-06 had problems. SOme were minor, some were severe. If you Google a little more you should find a listing of the known bad lots. Because of this, I would never buy this ammunition outside of it’s original packaging, seperated from it’s lot number. That being said, I have a known good lot and it is quality ammunition. It shoots better in my M-1 than the supposedly excellent Danish surplus.

My question would be why did some lots go bad in storage and others remain good. Certainly they all passed the QC testing at manufacture. Can poor storage cause defects like severe case splits at the head?

AKMS


#8

Splits at the head ( “K” splits etc) are caused by bad Internal drawing ram radius design, leading to over-stressing the case head internally, at the joint of the web and body. As this stress takes time to develop into a full-blown stress fracture ( brass ageing) it takes several years to become evident on firing.
A similar even happened to Kynock .30/06 made in the early 1950s, but the matter was rectified as it showed up after about a year in store, and .30/06 was made in Batches at the time, as required, and not for “Reserve store”). The incorrect tool ram radius was corrected, and the problem disappeared.

Later PS ( and PSD) don’t show this head split tendency, so the problem must have also been recognised early on.

I have not heard of any earlier KA (?Korea Arsenal?) .30/06 ammo being affected. Maybe because this ammo was Berdan primed initially? ( Different ram design and or heading ram support?). I suspect the KA ammo was made on the earlier Japanese Inchon Factory machinery ( if such survived the WW II and Korean War at all?). The Japanese Army Arsenal based at Inchon and hinterland was examined in 1945 ( & photographed) by the US Ordnance special teams, so their reports are now available in the Archives as declassified material for public use.

Regards,
Doc AV
AV Ballistics


#9

Good info DOC.

Looking at the list of known Korean “PS” lots that were imported, there is a distinct group of lots within that list that have shown case head splits.

The list begins at “PS 2-033” (headstamp unknown. PS 74 or 75 maybe?) and ends at “PS 2-205” (PS 76).

The problems begin around lot “PS 2-152” through “PS 2-165”. Headstamps are “PS 75”. Lots after these appear to be OK. My lot is “PS 2-202” with “PS 76” headstamp and is A-OK .

How long of a production span would this run of 13 lots account for? A week? A month? Most of the lots in this range have reports of severe splits, blown primers, etc…

Maybe they tried some new or different tooling. It seems as though this “bad” ammunition is confined to a short period of production not related to start-up issues or the beginning of production. Any ideas why the problems are isolated like this?

AKMS


#10

I tossed a bunch. I can get more 06 brass…