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 FYIRan a mini experiment on case dimension change on once fired Lc 74 .308 cases before and after Full Length sizing. Base diameter before = .4705" . After .468" The change in case length varied .003" to .004" LONGER.  Who knows maybe this will be helpfull to someone some day?  rogerOld age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone.. | ||
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The brass has to go somewhere when it is squeezed back to the smaller size. That's why we trim case length after a few cycles.. By the same token, when fire forming Ackley Improved cases, the OAL of the parent case shrinks by as much as .012" or more if I remember correctly. GOOGLE HOTLINK FIX FOR BLOCKED PHOTOBUCKET IMAGES https://chrome.google.com/webs...inkfix=1516144253810 | |||
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10-4 WJ- Another contributer is draging the case out of the die over the expander and some times when tight getting slight elongation.  rogerOld age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone.. | |||
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If, after FL sizing, you measure the depth of the primer pocket, you will notice that it is shallower and has lost some depth. When cold worked, brass does indeed expand in all directions, front and rear. Therefore, to restore the primer pockets dimensions and depth, I routinely clean them out with a pocket uniformer and it shaves a little every time. André DRSS --------- 3 shots do not make a group, they show a point of aim or impact. 5 shots are a group. | |||
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roger -- the resizer is making it longer .. take the expander out and retry.. you'll get the same results #dumptrump opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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I was thinkinking of doing just that.Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone.. | |||
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 Did three more cases from the same lot. with the expander removed. The stretch was as much as .007". Resized the same three with the expander in the die. Little if any change in lenth. This small sample does not prove ,however, that a tight neck does not cause case elongation.Variables such as thick necks or hardend brass do tend to lengthen the cases and to the point that the shoulders move out and prevents chambering. Through the years I have wittnessed this. Also checked to see if the primer caused the difference in measurements. The primers did not change the measurements. rogerOld age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone.. | |||
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The case "stretched" when it was fired albeit in diameter, not length. When you squeezed the diameter back to original, the brass had nowhere to go but forward, thus elongating the case. It wasn't "stretched" by the resize, it was pushed. GOOGLE HOTLINK FIX FOR BLOCKED PHOTOBUCKET IMAGES https://chrome.google.com/webs...inkfix=1516144253810 | |||
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I guess I could have been more explicit and used better terminology but it seems you got the picture. rogerOld age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone.. | |||
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The whole case changes to fit a particular chamber as chamber vari as reamers get used and wear, so no chamber is the exact same..Hot loads add to the delima in that we measure pressure by head expansion, and case length, thus we resize and trim cases..You can play with the expander ball and get some relief there, and also file it down some and get a tighter grip on the bullets, and even that will increase pressure by perhaps one or two PSI's.. Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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