Stupid Question about Full Length Sizing?

kilk14

kilk14

New member
Hey guys,

I almost feel dumb for not understanding this, but my question is: After full-length sizing a cartrige (300 WSM in this case) should the once fired, full length sized brass be the same size as new brass (width of course)? The reason I ask is that I'm using an L.E. Wilson Trimmer and there are two different sizes of holders for the .300 WSM. There is one for Full Lenth Sized/New brass, and one for once fired brass. The problem I'm having is that after I full-length size my brass it doesn't fit the Full Lenght sized holder. Just want to make sure my Die isn't out of whack or something. Please help.
 
In answer to your question, yes and no.

First it will be the same size diameter wise, but it will NOT be the same size length wise, which is why it will need to be trimmed.

When fired the case will "stretch" in all directions.

IE: It will be a larger diameter and it will also be longer.

The full-length sizing only addresses the diameter size of the brass for its full length. The trimming process is what takes care of the extra length.
 
The holders for the wilson trimmer, when used with straight walled cases, need two different holders.

Since you have only sized the necks, the body is still "fired size",so use the holder for fired cases... the cases will NOT fit the "full length sized" holder.

In other words, nothing is wrong with your cases, you have the wrong holder.
 
Thanks for you help so far. I'm well aware that case trimming is what will make the length uniform. The diameter is what I'm going after. I want to know why after length sizing, my diameter isn't the same as it is on a new, never fired brass. My question probably is a little foggy.

What I'm saying is that I HAVE full-length sized the once fired brass with my RCBS Die. I want to know why my brass (after being sized) won't fit the shell holder for the "new brass/full length sized brass"?? CatShooter, you seem like you're familiar with the trimmer I'm speaking of. Am I not length sizing my brass right?
 
Misunderstood your orginal question - I thought you neck sized (it's only 2:30 and it's already been a long day), so lemme go through it again.

I AM familar with the Wilson, I have owned one for many years.

"After full-length sizing a cartrige (300 WSM in this case) should the once fired, full length sized brass be the same size as new brass (width of course)?"

Full sizing dies rarely return the case to the "new case" size, unless they are marked as "Small base" dies. Your FL die will take the case back most of the way, but not back to "new case" diameter.

Plus - dies, chambers, and case holders vary, due to tolerances that all these things have.

With Wilson case holders, if the case has normalish taper like a .223, then both fired cases and FL sized cases will fit, just the sized case will go a bit further into the holder.

But, with cases that have minimum taper like the WSM family, you need a holder for either fired, or sized.

Now... because of the variation from "max" and "Min" reamers, sometimes you can have a situation like this, where the sized case still won't fit. You obviously have a sizing die cut with a new reamer, and so the die is "max" in width... and the holder is "min" in diameter.

Your die isn't "out of whack", just a minimum dia.

As I recall, the Wilson instructions state that if there is a fiyt problem, send them the die, and two or three cases and they will replace the holder with one that will fit.

You are not the only one to have this problem... it is fairly common with cases that have very straight sides, with very little taper.
 
KILK13,
Will your once fired/resized brass chamber easily? I reload 270 WSM and 300 WSM and have found that you have to set your dies so that the press cams over at the top of the stroke.

Set your die so that the shell holder makes contact with it and resize a case. Back the die off a half turn and resize the same case. Keep backing off and resizing until you get a klunk-klunk sound and feel at the top of the press stroke. This is the press camming over. This camming sets the shoulder back a couple thousanths more and fully resizes the brass. Due to the high pressure that they run at and the case shape WSM's require this to chamber properly and in your case to fit your trim die. I hope that this makes sense and cures the problem.

Brent
 
Brent,

This is great information you gave me. One question...do I need to do this with every case I resize, or once the die is set is it set? Like I said, this is my first experience with sizing WSM cartriges so I don't know much of anything. What exactly is "camming over"? I think I know, but I want to make sure. Your help is greatly appreciated. Thanks again!
 
Once you get the die set, you only need to resize each case once. The repeated sizing while backing the die out is to determine the point were the press cams over. It is easier to see the camming over than explain it. When you get your die set and get the klunk-klunk sound, look at the linkage between the handle and the ram and you'll see it break over center.

Brent
 


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