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A post on behalf of Henry Childs.....
- Thread starter Rich De
- Start date
......... What more needs to be said?
T
tim in tx
Guest
henry
i think everybody pretty much summed it up and i can only say i would back you anytime you need it as well,thanks for your post.and it is always a pleasure shooting with you and seeing the latest cool bullet projects in the works. tim in tx
i think everybody pretty much summed it up and i can only say i would back you anytime you need it as well,thanks for your post.and it is always a pleasure shooting with you and seeing the latest cool bullet projects in the works. tim in tx
Y
-Yo-
Guest
Well, by in large. We all have out blindsides, and supposedly, one of the reason Henry quit posting on BR Central was Jackie Schmidt's and my chiding him that regardless of the current state of engineering theory, VV N133 did show grouping (agging) changes when there was a significant change in humidity. Henry said this wasn't so; wasn't possible, wasn't in the books or the test results from powder manufacturers.
Charles Ellertson
Interestingly in the current Norma load manual, Sven-Eric Johansson, head of ballistics at Nexplo/Bofors, offers an extensive discussion of powder moisture content, with test results demonstrating that a given lot of powder, if it dries out and has lower moisture content, will exhibit a faster burn rate. Likewise, if the same powder is allowed to absorb moisture (higher moisture content) it will exhibit a slower burn rate. Johansson explains that most powders, as they leave the factory contain a moisture content of 0.5 to 1.0%, but this can and does change depending on the conditions of storage (arid/dry vs. wet/humid). The key fact here is that powder moisture content CAN and DOES change and such change DOES affect how it burns.
I remember Henry's statements regarding humidity and powder. Apparently Bofor's lead scientist disagrees, at least with respect to how powder moisture content can change during the course of long-term storage.
Link: http://accurateshooter.wordpress.com/2008/09/10/tech-tip-humidity-can-change-powder-burn-rates/
I imagine Henry would agree with the Norma findings. What Jackie Schmidt & I (& others) were talking about was a fairly big humidity change during a match. Jackie had a cheap Raido Shack meter that measured relative humidity, and when it dropped to a certain number (believe it was 40%, could be wrong), he could predict that he'd have to change his powder charge using N-133 -- and the new charge weight would shoot better until the RH went back up. His shooting proved the prediction correct, and it was both repeatable & measurable. Whether the humidity was the *cause* or not, it certainly correlated, & as such a phenomena that needed explanation if you weren't going to allow that humidity could affect tune.
But that's just stuff. Henry remains a friend.
But that's just stuff. Henry remains a friend.