ORIGINAL: bigcountry
ORIGINAL: Brush hunter
ORIGINAL: bigcountry
ORIGINAL: Brush hunter
Yes i do and have proven it.
Ok, do you have any pressure data? What was your technique for measureing pressure? Piezo, or Copper under pressure?
it was a few years back and i'm still looking for the data, however we used a chronograph, and mesured vel. We used 50 cases from the same lot all fired once. half were cleaned half were not, they were all loaded with the same bullets, primers and power from the same lots. the loads were all shot in 5 shot groups, the gun was cleaned after each group. The dirty rounds all fired between 5 to 8 flbs higher than the clean ones. it may not be 100% accurate, but I'm saying higher vel. =higher pressure.
Maybe, I can't really say 5-8fps is better than error of measurement. I have chono'd a lot of loads, I rarely see std dev. less than 8fps out of any load besides some very consistent 45ACP loads. I don't buy it, but I do respect that you are out there doing tests like these. I know I have done some off the wall tests which put biases in my mind. Most won't take the time to do tests on thier own and rely only on internet info or whats in books. So interesting tests.
.........Don't know what happened to my previous post. Went to edit it, and it disappeared.
Anyhow, I wondered if you have ever cut two casings apart at exactly the same place, say a given measurement from the head (one that has been fired once or not at all vs. one that has been loaded and fired to the point of being unreloadable anymore) and miked case wall thicknesses? Basically looking to see if a measureable buildup of residue was present. I'm sure you know various manufacturers can have different wall thicknesses also, and realize you stated you used the same manuf. and lot of cases. Also wondering if an analytical balance could show an increase in case weight with repeated firings..?? Primers would have to be weighed and separated so as not to invalidate reults, etc......
Also wondering if the 5-8 fps continues to multiply itself with repeated loadings? Is it incremental?
PS.....I should have sent this reply to Brush hunter, not big country.....