jessegibson1978
Well-Known Member
Can I reform 7 wsm brass to 325 wsm.
reworking brass
- Thread starter jessegibson1978
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I don't own either but I can give you a few things to look at so you can make a self determination.
You are going from a 7mm to an 8mm neck diameter. That means you will be thinning your neck when reforming. I like to go the other way (larger diameter to smaller diameter) and turn the necks if needed for uniformity and fitment to the chamber. It's not a big change so you should have adequate neck wall thickness to give good neck tension on a loaded round. You can actually calculate how much it will be thinned if you know how to determine the area of a circle and have a micrometer to measure neck wall thickness on the original case.
I will assume the shoulder on the 7mm is further forward than the 8mm reform so reforming would push the shoulder back reforming to 8mm dimensions. This would require trimming the case to the proper length but is a good situation to be in.
If the shoulder is further back on the 7mm you will want to adjust your die so you leave a bit of the neck (neck/shoulder junction) unsized so it acts as a false shoulder giving you proper headspace when fireforming the loads. This is a trial and error process if you don't have a cast of your chamber. Partial size it and see if it fits in your gun. If not, adjust the die down a bit more and try again.
A caution here is if the case needs to stretch more than ~.010" during fireforming you may not want to reform at all because it will thin the web too much. That could create an unsafe situation and cause the case to rupture.
You are going from a 7mm to an 8mm neck diameter. That means you will be thinning your neck when reforming. I like to go the other way (larger diameter to smaller diameter) and turn the necks if needed for uniformity and fitment to the chamber. It's not a big change so you should have adequate neck wall thickness to give good neck tension on a loaded round. You can actually calculate how much it will be thinned if you know how to determine the area of a circle and have a micrometer to measure neck wall thickness on the original case.
I will assume the shoulder on the 7mm is further forward than the 8mm reform so reforming would push the shoulder back reforming to 8mm dimensions. This would require trimming the case to the proper length but is a good situation to be in.
If the shoulder is further back on the 7mm you will want to adjust your die so you leave a bit of the neck (neck/shoulder junction) unsized so it acts as a false shoulder giving you proper headspace when fireforming the loads. This is a trial and error process if you don't have a cast of your chamber. Partial size it and see if it fits in your gun. If not, adjust the die down a bit more and try again.
A caution here is if the case needs to stretch more than ~.010" during fireforming you may not want to reform at all because it will thin the web too much. That could create an unsafe situation and cause the case to rupture.
jessegibson1978
Well-Known Member
Thank you for your reply. My problem is the shoulder on the 7 wsm has to be pushed back .050 I have done this to about 15 cases but accuracy is dismal about 1.5 at 100 and the neck is black. Not sure if its a brass thing or a barrel thing just trying to explore my options.
J E Custom
Well-Known Member
The 7 WSM is unique For the WSMs, but the 325 Wsm Can be made from the 300 WSM.
When you move a shoulder very much It can cause problems(As you are finding out), Except
when fire forming and the case cannot resist the pressure.
You can bump the shoulder after it has moved forward enough to cause problems but that is
normally only .002 or .003 Thousandths.
Long tapered shoulders (Like the H&Hs)can be moved back with some success because they
have 8+degree shoulder angles but when you get in to the 30 to 40degree shoulders that's
a different beast.
The cost of bullets,powder and primers are almost the same price as the brass, so the trouble
and barrel life are not worth it in my opinion.
Just buy new 325 brass and have fun.
J E CUSTOM
When you move a shoulder very much It can cause problems(As you are finding out), Except
when fire forming and the case cannot resist the pressure.
You can bump the shoulder after it has moved forward enough to cause problems but that is
normally only .002 or .003 Thousandths.
Long tapered shoulders (Like the H&Hs)can be moved back with some success because they
have 8+degree shoulder angles but when you get in to the 30 to 40degree shoulders that's
a different beast.
The cost of bullets,powder and primers are almost the same price as the brass, so the trouble
and barrel life are not worth it in my opinion.
Just buy new 325 brass and have fun.
J E CUSTOM
jessegibson1978
Well-Known Member
That is kind of what I was thinking. Thanks for your thoughts.
jessegibson1978
Well-Known Member
That is kind of what I was thinking. Thanks for your thoughts.
Last edited:
Annealing will help with reforming. The sooty neck is most likely caused by inadequate pressure and not expanding the neck fast enough to seal to the chamber. Again, annealing will help.
I would try a group of re-formed, fire-formed cases a second time before I pass judgement on accuracy.
J E is correct about it being a lot of trouble and you are better off buying the proper brass.
I would try a group of re-formed, fire-formed cases a second time before I pass judgement on accuracy.
J E is correct about it being a lot of trouble and you are better off buying the proper brass.
J E Custom
Well-Known Member
Just buy the Winchester brass. Much cheaper and it does well if prepared correctly.
J E CUSTOM
