Hello CGN reloaders,
I recently picked up a rifle in 7mm WSM due to the platform it was in... I was not particularly enamoured with the cartridge. It only took a few days to hit the component roadblock that accompanies this cartridge. After searching locally and online, I came up blank on 7mm WSM brass, and saw many posts where others were searching also. I also found many posts discussing making 7 WSM brass from 270 or 300 WSM. Most of these posts discussed various problems associated with making 7 WSM brass from other WSM cartridges. Due to the fact that the 7 WSM has the shoulder set further forward than the 270 or 300 versions, I assume to avoid chambering a 7 WSM in a 270 WSM rifle, the first step is to anneal the case (SEE UPDATE POST) and neck up to .30 cal if you start with 270, then running the case through the 7mm WSM FL die, with 300 brass you can anneal and then jump straight to the 7mm FL die... FL sizing will create a "false shoulder" which the cartridge can headspace on for fireforming. Another problem reported was that resized brass would require neck turning due to excessive wall thickness.
I found a batch of 100 pieces of 300 WSM brass and decided to test the process.
I first annealled the batch of brass;
I then ran it through the 7mm WSM FL die, this created the false shoulder;
I then loaded some 154 SP's over a reduced load of 32.0 grains of H4895, as I also wanted some trigger time on the rifle. I started with a test batch of ten rounds... all ten reduced loads fired without a hick-up and went into an inch @ 100 while fireforming (Note; I also fired 40 rounds of Win Silver Box 150 SP's and they sucked with 5" groups @ 100). The reduced loads blew out nicely;
The middle three are reformed 300 WSM cases, with a 7mm WSM case on either end;
After cleaning the brass, I mic'd the reformed 300 WSM brass and compared it to the headstamped 7mm WSM brass and discovered that there was no appreciable difference between the two. I loaded up the once fired 7mm WSM brass and the twice fired reformed 300 WSM brass and mixed them together and cycled them through the action in a blind test, I could not tell any difference between the two... I then fired ten four-shot groups with two of each cases in each group, they grouped to the same POI consistently.
So for you 7mm WSM shooters, the much easier to find 300 WSM brass is a quick and easy fix to your brass problems, without the much reported problems you may have read about. Good shooting.
Photobucket killed the photos, so I will replace them here;
I recently picked up a rifle in 7mm WSM due to the platform it was in... I was not particularly enamoured with the cartridge. It only took a few days to hit the component roadblock that accompanies this cartridge. After searching locally and online, I came up blank on 7mm WSM brass, and saw many posts where others were searching also. I also found many posts discussing making 7 WSM brass from 270 or 300 WSM. Most of these posts discussed various problems associated with making 7 WSM brass from other WSM cartridges. Due to the fact that the 7 WSM has the shoulder set further forward than the 270 or 300 versions, I assume to avoid chambering a 7 WSM in a 270 WSM rifle, the first step is to anneal the case (SEE UPDATE POST) and neck up to .30 cal if you start with 270, then running the case through the 7mm WSM FL die, with 300 brass you can anneal and then jump straight to the 7mm FL die... FL sizing will create a "false shoulder" which the cartridge can headspace on for fireforming. Another problem reported was that resized brass would require neck turning due to excessive wall thickness.
I found a batch of 100 pieces of 300 WSM brass and decided to test the process.
I first annealled the batch of brass;
I then ran it through the 7mm WSM FL die, this created the false shoulder;
I then loaded some 154 SP's over a reduced load of 32.0 grains of H4895, as I also wanted some trigger time on the rifle. I started with a test batch of ten rounds... all ten reduced loads fired without a hick-up and went into an inch @ 100 while fireforming (Note; I also fired 40 rounds of Win Silver Box 150 SP's and they sucked with 5" groups @ 100). The reduced loads blew out nicely;
The middle three are reformed 300 WSM cases, with a 7mm WSM case on either end;
After cleaning the brass, I mic'd the reformed 300 WSM brass and compared it to the headstamped 7mm WSM brass and discovered that there was no appreciable difference between the two. I loaded up the once fired 7mm WSM brass and the twice fired reformed 300 WSM brass and mixed them together and cycled them through the action in a blind test, I could not tell any difference between the two... I then fired ten four-shot groups with two of each cases in each group, they grouped to the same POI consistently.
So for you 7mm WSM shooters, the much easier to find 300 WSM brass is a quick and easy fix to your brass problems, without the much reported problems you may have read about. Good shooting.
Photobucket killed the photos, so I will replace them here;
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