7.5x55 Swiss - A study in brass
Posted: Sun Dec 31, 2023 5:02 pm
7.5x55 Swiss - A study in brass
I figure I should do some hunt and pecking on the key board not having much of any thing to do at the moment. Plus I was looking at the chickens doing their thing. If you can't eat them, join them is what I say. This is my journey to being a better steward of my brass, whether 7.5 Swiss or any others in the tunnel complex.
I used a .400 Hornady case comparator and my Mitutoyo caliper as my measurement tools. I am going on faith that RUAG Ammotec knows how to make uniform brass and all of the dimensions are close to being the same. The fun part, not, is setting up my testing equipment. I made sure the surfaces of the comparator and base were flat to each other by holding them up to the light and looked for any light that would show them as being canted in the calliper.
I grabbed one of my bags of 7.5x55 Swiss brass made by RUAG and measured a new case. The base to the datum line on the shoulder of a new un-fired case is 1.797 inches. The case length is 2.183 inches. So far, so good as they tell us up at the Home on sponge bath night.
Next I took my multiple times fired (Beats me how many times, some two, some three, question mark others) brass in my blue box and fired up the ol' spreadsheet. I will adjust my sizing die based on what the numbers tell me. Anyone who has reloaded ammo will already know this so this little exercise is for the rookies and casual readers of these words.
The spreadsheet revealed three cases were, 1.792, 1.794 and 1.803 at the shoulders. I don't have a guess for those. None of the brass had been annealed at the last shooting. The rest measured 1.808 to 1.813 inches. The majority is around 1.810-1.811
1.792 1
1.794 1
1.803 1
1.808 3
1.809 8
1.810 20
1.811 16
1.812 2
1.813 5
total 57
Here is what I found for case length. The trim length in several places says to cut them to 2.179 for the K31 platform. However, I am a founding member of BA, Brass Anonymous. "Hi, my name is Culpeper and I abuse brass." "Hi, Culpeper." I've never trimmed this brass. With the exception of a few pieces of .30-06 brass I neglected that part of the process. The numbers are all over the place.
2.162 1
2.166 1
2.167 2
2.168 1
2.171 1
2.172 5
2.173 3
2.174 4
2.175 2
2.176 3
2.177 1
2.178 3
2.179 8
2.180 1
2.181 1
2.182 1
2.183 2
2.186 1
2.187 2
2.190 3
2.191 1
2.192 2
2.195 2
2.199 2
2.202 1
2.206 1
2.207 1
2.230 1
57
Here ends the sad tale of my brass. The next chapter will deal with getting annealing and trimming to see if I can bring most of it back from the edge.
.
I figure I should do some hunt and pecking on the key board not having much of any thing to do at the moment. Plus I was looking at the chickens doing their thing. If you can't eat them, join them is what I say. This is my journey to being a better steward of my brass, whether 7.5 Swiss or any others in the tunnel complex.
I used a .400 Hornady case comparator and my Mitutoyo caliper as my measurement tools. I am going on faith that RUAG Ammotec knows how to make uniform brass and all of the dimensions are close to being the same. The fun part, not, is setting up my testing equipment. I made sure the surfaces of the comparator and base were flat to each other by holding them up to the light and looked for any light that would show them as being canted in the calliper.
I grabbed one of my bags of 7.5x55 Swiss brass made by RUAG and measured a new case. The base to the datum line on the shoulder of a new un-fired case is 1.797 inches. The case length is 2.183 inches. So far, so good as they tell us up at the Home on sponge bath night.
Next I took my multiple times fired (Beats me how many times, some two, some three, question mark others) brass in my blue box and fired up the ol' spreadsheet. I will adjust my sizing die based on what the numbers tell me. Anyone who has reloaded ammo will already know this so this little exercise is for the rookies and casual readers of these words.
The spreadsheet revealed three cases were, 1.792, 1.794 and 1.803 at the shoulders. I don't have a guess for those. None of the brass had been annealed at the last shooting. The rest measured 1.808 to 1.813 inches. The majority is around 1.810-1.811
1.792 1
1.794 1
1.803 1
1.808 3
1.809 8
1.810 20
1.811 16
1.812 2
1.813 5
total 57
Here is what I found for case length. The trim length in several places says to cut them to 2.179 for the K31 platform. However, I am a founding member of BA, Brass Anonymous. "Hi, my name is Culpeper and I abuse brass." "Hi, Culpeper." I've never trimmed this brass. With the exception of a few pieces of .30-06 brass I neglected that part of the process. The numbers are all over the place.
2.162 1
2.166 1
2.167 2
2.168 1
2.171 1
2.172 5
2.173 3
2.174 4
2.175 2
2.176 3
2.177 1
2.178 3
2.179 8
2.180 1
2.181 1
2.182 1
2.183 2
2.186 1
2.187 2
2.190 3
2.191 1
2.192 2
2.195 2
2.199 2
2.202 1
2.206 1
2.207 1
2.230 1
57
Here ends the sad tale of my brass. The next chapter will deal with getting annealing and trimming to see if I can bring most of it back from the edge.
.