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November 10, 2009, 09:38 PM | #26 |
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Join Date: October 26, 2009
Location: Pointe Coupee, Louisana
Posts: 772
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pistol brass gets SHORTER instead of longer
I'm just a dumb Louisiana Coonass who has reloaded for about 50 years and would be eternally grateful if you would explain this phenomena to me.
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Those who beat their guns into plows, will plow for those who don't.-Thomas Jefferson |
November 10, 2009, 10:03 PM | #27 |
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Join Date: November 8, 2007
Posts: 2,001
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Why do you need an explanation?
You DO have a caliper don't you? Just measure them and you will see that they are shorter than they were before they were fired the first time, and they don't grow with additional firings.
Seems like most people know that happens. WHY it happens would be speculation. SL1 |
November 10, 2009, 10:54 PM | #28 |
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Hog Buster, here's as good an explanation as I've ever read. If I may borrow from one of UncleNick's posts earlier this year....
http://www.thefiringline.com/forums/...44&postcount=8 |
November 10, 2009, 11:08 PM | #29 |
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Join Date: October 26, 2009
Location: Pointe Coupee, Louisana
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Gee, thanks for the.....er....explanation? And to think all these years my caliper has been lying to me. It 's been showing my fired pistol cases length increasing. Hmmm....I wonder why there's so many pistol case trimmers on the market? Seems there wouldn't be too much call for them if the fired cases got shorter....... I guess that if the case was fired enough times it would shorten all the way back to the head.........Oh well, live and..... learn?
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Those who beat their guns into plows, will plow for those who don't.-Thomas Jefferson |
November 11, 2009, 02:38 PM | #30 |
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Join Date: November 11, 2009
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A caliper is nice but you sure don't "need" one. You can eyeball it pretty doggone good with the right ruler. But you can get a perfectly good dial caliper from Harbor Freight for a song.
If you study your cases closely thru the various stages you should be able to compare to a factory round and tell when you've achieved a well formed round. The tolerances are so very close that slight differences can have a profound result from one gun (or barrel) to the next. A 200fps difference is minor. A half-inch in length can be a tremendous factor in velocity depending upon the bore diameter, case capacity, burning rate of the charge, the firmness or lack of a crimp, profile of the projectile, hardness and smoothness of the projectile. I'd be thinking of using Universal myself. I'd have to consult a manual but isn't HS6 wise only in firm crimped heavier weight loadings? I know if my fired cases continued to shorten I'd make an appointment with a gunsmith to inspect my chamber, lockup, and bore. While a straightwall case isn't stretched during a full length resize because we don't have to expand the neck on the upstroke; if its not staying the same or growing just a tad its getting wider. How far away would you be from case failures? Regards, TB |
November 11, 2009, 02:54 PM | #31 |
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Join Date: July 11, 2009
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oh what do ya know...i get my calipers (2 day free shipping from amazon) and i had those bullets seated almost EXACTLY to the recommended depth
one odd thing though i notice with looking at a few of my cartridges is with these 9mm cases they seem to never be factory spec diamter, alot of them are closer to .380 rather than .35. but i dont think ive had any problems in that respect. it would be good to know what kind of deviation is acceptable i think most of my issues would be from having undercharged cases not working the action all the way because i was using charge numbers from that stinky hornady manual and not verifying the actual velocity out of my gun with a chrono. (which i will have tommorrow i hope) |
November 11, 2009, 04:32 PM | #32 |
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Join Date: December 4, 2008
Location: Dallas, Tx.
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Once you get the chrono your trip to the range is going to change a bit. Instead of telling the wife you'll be back in an hour, you'll have to change it to 2 or 3 hours.
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November 11, 2009, 06:41 PM | #33 |
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Join Date: March 9, 2008
Location: Southern California
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I am sorry but I have not been able to see 1/1000" or even 1/100" with my eye? Not trying to be a wise guy but my Engineering Education is kicking in!
Also brass does flow, expand, lengthen and or deform under pressure, even as little as 9000 CUP! All cases will need trimming if shot enough, the law of physics and energy will kick in at some point. Not trying to start a battle or imply anyone is less than knowledgeable but most of my brass has lengthened with enough shooting and I personally am too blind to be able to see if brass is too long or some other minor dimensional issue? Love my Caliper, I have three but can only use one at a time! That being said, I read the post referenced in here and still did not see where the point of zero expansion/length was proven. I can send you some references concerning steel/metal/brass, heat, expansion, loading (lateral, vertical and horizontal) that prove all metals expand, malleable and non malleable, hardened, annealed or otherwise! Again not trying to make enemies here and not trying to disparage anyone! My 2 Cents worth! |
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