21 November 2005, 22:28
MADRIDresize Norma cal.308, help me
In some cases of Norma mark and cal.308 that seemingly they have been shot only once, and in all those that any previous mark didn't exist, after carrying out the resize operation a mark it appears in the body of the case, parallel to the axis of the case head and next to the edge, with ring appearance.
(I carried out the resize with RCBS materials, a press RS3, a new mould Competition Die Set and with a standard shell holder num2.)
A friend has told me that it could be a problem of adjustment of the mould, because this one is too short, or perhaps the shell holder is inappropriate. I have used a standard shell holder RCBS, num 2 (for cal.307), although the suitable one for RCBS is the num.3.
Therefore it arises me the following questions:
1. I am not sure of understanding the phenomenon. I don´t know how this tension appears and how it is produced (I suppose that it can be a difference of tensions when the piston of the press is working and to exercise pressure to the recalibrated) and also I don´t understand why "the ring" appears exactly in this place (at 7mm more or less) and not in another part of the case (I suppose that with different marks of cases it could be alter, due of the characteristics of the alloy).
2. I also would like to know how I could know if the mould is very short regulated.
3. In case of that being motivated by the shell holder (appropriate for the 307 and inadequate for the 308) How can affect that difference so much to the tensions during the resizing?
photo
http://img385.imageshack.us/img385/5812/fotovainas6dg.jpgthanks, from spain
21 November 2005, 22:36
ramrod340Looks to me like it is just the normal ring caused by the edge of the reloading die.
But then again I have been wrong before.
21 November 2005, 22:48
StonecreekMadrid:
I take it that you are loading .308 Winchester (7.62 Nato)?
The ring you see is quite normal and represents the point at which the case head/body is thick enough to resist expanding against the gun's chamber walls. The thinner brass ahead of this ring expands until it is constricted by the chamber walls, then when you run it into the resizing die (you call it a "mold"), the die reduces it back to a standard maximum diameter. The brass below this ring is not touched by the die because it has not expanded enough to exceed a pre-determined maximum standard diameter. This mark is often called the "pressure ring".
I am unsure of your reference to a ".307" shell holder. At any rate, the die (mold) should not normally be screwed all the way down against the shell holder, but rather screwed only so deep as to resized the brass enough that it easily re-enters the gun's chamber. Sizing any further may creat excessive headspace (cartridge significantly shorter than the chamber), which will cause work-hardening of the brass and cause it to fail due to the head separating at the pressure ring within in a few firings.
21 November 2005, 22:50
Stonecreekquote:
Originally posted by Stonecreek:
Madrid:
I take it that you are loading .308 Winchester (7.62 Nato)?
The ring you see is quite normal and represents the point at which the case head/body is thick enough to resist expanding against the gun's chamber walls. The thinner brass ahead of this ring expands until it is constricted by the chamber walls, then when you run it into the resizing die (you call it a "mold"), the die reduces it back to a standard maximum diameter. The brass below this ring is not touched by the die because it has not expanded enough to exceed a pre-determined maximum standard diameter. This mark is often called the "pressure ring".
I am unsure of your reference to a ".307" shell holder. At any rate, the die (mold) should not normally be screwed all the way down against the shell holder, but rather screwed only so deep as to resize the brass enough that it easily re-enters the gun's chamber. Sizing any further may creat excessive headspace (cartridge significantly shorter than the chamber), which will cause work-hardening of the brass and cause it to fail due to the head separating at the pressure ring within in a few firings.
22 November 2005, 00:20
Paul BStonecreek. I think he means the .307 Winchester which uses the shell holder for the 30-30 Winchester. The die for the .308 and .307 are the same, but you need the two different shell holders.
Paul B.
23 November 2005, 13:32
MADRIDquote:
Originally posted by Stonecreek:
Madrid:
I take it that you are loading .308 Winchester (7.62 Nato)?
I am unsure of your reference to a ".307" shell holder. At any rate, the die (mold) should not normally be screwed all the way down against the shell holder, but rather screwed only so deep as to resized the brass enough that it easily re-enters the gun's chamber. Sizing any further may creat excessive headspace (cartridge significantly shorter than the chamber), which will cause work-hardening of the brass and cause it to fail due to the head separating at the pressure ring within in a few firings.
Yes, loading .308 Winchester , and de RCBS standard shell holder num2 (for .307W )
22 Savage High Power
25-35 Winchester
6.5mm x 55 Swedish Mauser
7-30 Waters
30-30 Winchester
307 Winchester
7.5mmx54 French MAS
7.5mm x 55 Schmidt-Rubin
32 Winchester Special
32-40 Winchester
356 Winchester
375 Winchester
38-55 Winchester & Ballard
Thanks
23 November 2005, 13:53
Thomas MAre you saying that you use a shell holder for the 307 win? It is a litle to big for the 308 but this is not the cause for your problem. I think allso that it's the normal pressure point you have.
23 November 2005, 15:30
ClassicAlMadrid:
In my experience, Norma .308 Win brass is softer than American-made brass. This results in greater expansion of the pressure ring with the Norma brass, and consequently greater burnishing of the ring on resizing.
Cheers, Al
23 November 2005, 21:52
MADRIDThomas M & ClassicAl :
I also believe that, but certainly i am not sure.
ramrod340 , Stonecreek , Paul B
Thanks a lot, and HAPPY THANKSGIVING DAY from Spain