300 WSM Winchester brass, stretching issue.

Crossbuck

Crossbuck

CGN Regular
Rating - 100%
18   0   0
I ran into an issue when trimming 300 WSM cases last night. I use a RCBS Trim-Pro 2 trimmer. This trimmer holds the brass with a "C" shaped shell holder which fits in shell's ejector groove (i.e. between the rim and the body).

The diameter of the case across the ejector groove has increased to a point where I was having a really hard time fitting the cases on the shell holder. This brass was purchased new and fired twice with medium loads (165 grs bullet, 66,5 grs of IMR-4350). I have never seen any signs of high pressure while shooting this load.

Is it normal to see stretching in this part of the case or am I dealing with weak brass?
 
I believe you are referring to extractor grove have you checked shell holder for a buildup of dirt this can happen over time. good luck
 
Crossbuck

Any expansion measured just above the extractor groove over .001 is a sign of excess chamber pressure. (from a unfired case to a fired case)

On the flip side of this it could be soft brass but it would be accompanied by loose primer pockets.

Either way the brass is toast and belongs in the scrap brass bucket if it has enlarged/stretched that much.


base%20expanshion_zpss3c0gjcm.png


But now that I think about it my wife's bottom got to be the same way after 40 years of marriage and I know better than to say a word about it.
 
Crossbuck; Are you working with Federal Brass? That stuff is soft, and expands readily, even with moderate loads.

If It is, you need to replace that crappy brass with some Winchester or R-P Brass.

Regards, Dave.
 
Hello all,

I really appreciate your insight (and Bigedp51's sense of humour!)

I just double checked my case trimmer to make sure. Yes, I am using the #43 shell holder and it is clean. I am using Winchester brass which I purchased new. The brass has been shot twice and was necked-sized only. I observed no flattened (or leaking) primers, no sticky bolt lift and no visible stretch marks on the cases when I shot them previously. The primer pockets felt nice and snug when I reprimed the cases (after wrestling them into the trimmer...). I think Bigedp51 hit it right on the head. The cases have stretched and will need to be recycled after being shot 3 times. Is this normal with a 300 WSM?

My loading manuals (Nosler and Hornady) do not give me a measurement for the extractor groove diameter of a 300 WSM and, surprisingly, I couldn't find it on the web either...Does anyone have this piece of information?

Would higher quality brass solve my problem or am I better off developing a new load?

Many thanks.
 
Crossbuck

The bucket below contains over 95% of factory loaded Federal .223/5.56 cases with over sized primer pockets after the first firing.

193natorejects001_zps87560a0a.jpg


It was a little aggravating to clean and prep these case for reloading only to insert a prime and find out my work was for nothing.

But the problem was not only soft brass on top of this the cases were much thinner at the web flash hole area. And this made the cases weaker and more prone to excess base expansion and giving the impression of a over pressure condition.

federal_zpsbp4r0zok.jpg


The answer to this problem was in a AR15 forum by a smart moderator and top notch reloader. All you needed to do was make up a 2 inch rod and measure your web thickness, and the thin cases went into the scrap brass bucket.

IMG_2028_zpsb357ed59.jpg


IMG_2030_zps54dd0d9e.jpg


You say it is Winchester brass which might be just one bad batch of brass but also remember this. After Winchester lost the contract to produce ammunition at Lake City they fell on hard times. And then Winchester sold off its brass manufacturing plant and now buys brass from the cheapest bidders.

So just check some of your cases as above and see if the cases are thicker and made Ford Truck Tough, or made like a cheap Chevy truck. :evil:
 
W-W is usually one of the toughest brass out there and least likely to expand in the web area..........however I wasn't aware of their sale of brass making equip, biged just mentioned, so who knows now ????????? If you wish to use your cases again, I use one specifically for the 404 Jeff. The 404 Jeff opening measures .490 and will allow the WSM even expanded to enter easily. Mine has no number and is just marked 404 Jef, I ordered it right from Huntingtons. This is cheaper than replacing all your brass if they still chamber OK and hold primers tight. The other option is to just open up the throat on the shell holder a bit...........Dremel with small sanding drum and remove a few thou from the throat all the way round........it's easy, and have done this with one of my #4s.......can't imagine why I might have needed to do that......:redface::redface: I just hate scrapping brass if it still holds a primer.....
 
Very useful tips and advice. I will likely invest in a 404 Jeffery shell holder and monitor the primer pockets (and other pressure signs) closely.

The rifle is a Tikka T3.

Cheers!
 
You must log in or register to reply here.
Back
Top Bottom