Originally Posted By: Sfsmedic
I disagree and an easy way to find out. Fire a few cases. Load them in the gun and then manually extract them. See if lock up isn't extremely tight.
I never said I bump back .004 each time. I said I bump .004 from chamber size.
That makes no sense... you either set your die to bump 0.004" or you don't - and if you do, then each time you size the case, you shove the shoulder back 0.004" - and each time you fire the case, you move the head back 0.004" - that is how cases loose their heads!
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Also five firings from 1.350 resized to 1.346 each time equals .004 each time it's not accumulated math.
Actually, it is - every time you push the shoulder back, the case gets shorter - when you fire it, the shouldeer does NOT move forward, the case stretched at the web.
Then you push the shoulder back, and then stretch the web... and on and on and on...!
These are both bolt guns that get neck sized multiple times until the bolt is hard to operate than needs a .002 shoulder bump to start over. You have to bump them back or they will not get proper lock up and then the firing pin might just go tap instead of bang and you will be wrestling it trying to get it to come unlocked to load a different round.
This is up there in the dumbest things said this week!!! You know doodley squat about this stuff.
Case crush is desirable in a bolt gun - and no way does it interfere with lock up... or cause a firing pin tap.
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This is addressed in Dave Brennan's book Precision Shooting: Reloading Guide and my technique I'm discussing is from his pages addressing shooting the AR
I briefly knew David Brennen - he lives about 5 miles from me - he is out of business for good reasons.
He once published that when a bullet goes below the speed of sound (~1085 fps) it turns 45 degrees down and flies to the ground (that was the end of our friendship). So, I am not impressed by your name dropping of the name David Brennen.
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This is the tool I use to measure fired brass and determine chamber size. I measure several cases to determine initial length to test with on a new rifle.
http://www.hornady.com/store/Headspace-Gauge-Kits/
This tool has a built in error of 4 to 7 thou - I have two of them.
They first one was so inaccurate, that I bought a second, thing there was a problem wiht the first - but the same problem exisss with the second - some nit-wit at Hornady uses a counter sink and cuts a bevel on the touch surface of the syinder = which causes a shorter reading.
Get a "real" headspace gauge and measure it with your Hornady tool and it will measure shorter than the actual engraved numbers on the gauge.
Hey, Higgy... pay no attention to this load of cow poopie!!