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Expanding then sizing belted magnums - partial update

This topic can be found at:
https://forums.accuratereloading.com/eve/forums/a/tpc/f/2511043/m/3981086062

18 July 2020, 01:15
metalman29
Expanding then sizing belted magnums - partial update
I posted same time ago about having case head separations on the second fire of a 338 WM case. An image from that post is below. The images shows a virgin brass, the first fire, and then the separation after reloading after setting the shoulder back 0.003".




Given my argument that necking occurred on the first firing, two options were suggested. The first is fireforming with the bullet in the lands. The second was to expand the neck then resize it back down.

I purchased a 35 cal neck mandrel and easily expanded the necks using a simple lee decapping die. I then sized the brass until I could just close the bolt with little resistance. The image below is a comparison of the first fire previous shown compared to the wall above the neck when I used the expansion first technique. It is the same load and same brand of brass.

I think this is significant headway to getting a few shot out of the brass. I think there is still some local elongation. I do think for the remainder, I will size the brass where the bolt is a bit stiff to close for this first shot as I think I went a bit farther in setting the shoulder back then I needed.



Thanks for the suggestions.
18 July 2020, 03:48
Bobster
http://www.larrywillis.com/300winmag.html

Why are you setting the shoulder back .003? It seems like you are asking for a case head sep. I would think your best bet is to case form with a bullet in the lands, then use a collet neck sizer and the above die to handle the bulge above the belt.
18 July 2020, 05:49
craigster
Bobster, thanks for the link. One of the best things there is "My Favorite Quotes".
19 July 2020, 02:31
Atkinson
I suggest that you reload your case by neck sizing on the shoulder and not the belt....003? where did excess head space come from in your agenda as a process to handloading?? Better shoot with both eyes closed~! old


Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120

rayatkinsonhunting@gmail.com
19 July 2020, 06:36
JTEX
You have something weird going on if in fact you are only bumping the shoulder.003 and getting case head separations........

I shoot for .002 on all my accuracy stuff. A human hair averages .002.......

It seems to me that your chamber may have excessive headspace getting all that growth in the first firing. Was it me the first thing I would do is check my headspace.....

Excessive headspace is not a problem if you know it's there and work your brass accordingly.

I bet that's why your "false" shoulder worked, you actually got jam on your brass and it didn't grow from the web. Looks like you are on the right track.
20 July 2020, 11:46
sambarman338
quote:
Originally posted by craigster:
Bobster, thanks for the link. One of the best things there is "My Favorite Quotes".


The world I see just now reminds me of an incipient head separation.