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7.62x39 brass reloaders...need your opinion on this.

3K views 8 replies 6 participants last post by  Sawfish 
#1 ·
Picked up some Brass cases in 7.62x39 at the funshow over the weekend and was prepping the cases today. After tumbling to clean I ran them thru the RCBS AR group sizing & decapping die (the set in the black box) that I have for 7.62x39 and noticed a "ring" appearing at the base of some of the brass (Geco headstamp)...

My question is will this be an issue or is it just a peculiarity to this brand of brass or maybe just these fired cases ??...Here's a pic of the Geco case in question (top) and a PMC case (bottom) that were both run thru the same setup. Some of the Geco cases were a bit harder to get the press to "cam over", but not all of them. Also had to trim the case rim on three of the Geco cases as they were .007 in. too large and wouldn't fit in the shellholder.



 
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#2 ·
I had some O&A Olympic Arms Greek made 7.62x39 cases that were like that after sizing. It appeared to me the case web was not as thick as it should have been allowing the brass to bulge at the base more than it should. I believe it was a case manufacturing defect not a headspace or chamber issue.
 
#3 · (Edited)
I just processed about 200 pieces of once fired X39 brass I bought at the LGS that came from the local range and had about 5 cases like you posted all of which I just tossed,it was a mixed bag of brands but most of the fails were PPU. I've reloaded this caliber for over ten years and fired all brands of brass in my SKS rifles and never experience that from any of my cases PPU or otherwise fired in my rifles. Not all rifle chambers are alike and some have oversized chambers and can over expand the brass especially if it's of the thinner case wall variety.
 
#4 ·
I have had the same issue. If I am not mistaken it was the Geco ones also. Can't verify since I did toss them after testing. They will get stuck in the chamber other than that the rest of the brass I have not had an issue with as of yet.
 
#6 ·
I have exactly the same problem with range pick up brass that I bought from a surplus brass vendor. Some of the cases are GECO, but not all of them. I was setting up my reloading dies using a Wilson case gauge so I could size the brass to SAAMI specs. Unfortunately, I have been unable to size the brass down enough to fit entirely within the gauge, even using Imperial Die Sizing Wax as a lube.. I have reloaded once fired brass that was fired in my own guns (AKS and SKS) without any such problem. I think the pick up brass was either machine gun fodder or fired in guns with overly generous chambers. I experienced this same problem with 30/06 and .303 British brass that had been fired in military guns with sloppy chambers. I am going to try sizing the brass in two stages using an interim sizing die. Will report on this later.
 
#7 · (Edited)
UPDATE: I was using a Lee shellholder, so I thought I would try an RCBS to see if there was any difference. No offense intended to Lee, I picked RCBS because based on my use of the RCBS priming tool, some of their shellholders seem to have more clearance between the top of shellholder and the base of the sizing dies. My thinking was that I might be able to gain enough to iron out the offending ring, but I first needed to get an idea of what I was facing. SAAMI specs for the 7.62 x 39 call for a maximum case head measurement of .443. I gad some new unfired Privi brass on hand that gave me a case head measurement of .438. I had a number of samples of the RPU (range pick up) brass, and measured samples of the following Fiocchi; PMC; GECO; ICC; R-P; F-C; and Privi. I measured a minimum of 5 cases of each brand. Measurements ranged from .439 for R-P to .4415 for GECO. None of the fired cases measured above SAAMI maximum for CHE (case head expansion. There were significant variances within the same brand of brass, which indicated those were fired in more than one gun. This led to the following observations: 1. There was nothing to indicate that any of the brands of brass were defective; 2. The lack of any CHE exceeding SAAMI maximum indicates pressures were within reason; 3. Expansion of the brass causing hard resizing was occurring in the body of the case, and was most likely the result of the brass being fired in guns with oversized (machine gun?) chambers.

By sorting the brass via maker and using Imperial Sizing Die Wax I was able to size more cases to SAAMI Specs.. Changing shell holders did help in this regard, but I am also considering the possibility that my sizing die may be on the large side of SAAMI tolerances. Realistically, this may not make any difference depending on the rifle that you are using. So far as I can tell, the use of the 7.62 x 39 round in Southeast Asia predated any SAAMI listing for the cartridge. Therefore it is doubtful that the Communist Bloc nations were concerned with the SAAMI specifications, and even though ammunition may exceed SAAMI specs., it is entirely possible that it will functon in your rifle.
 
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