After bumping a batch of bullets, I noticed that the noses were not all alike. Checked everything on the press and bump die and re-bumped the lot. Still different. So I started measuring length. It varied alot, more than .015". I then went and checked the lengths of some bullets that had been lube-sized and GC'ed. They varied .010".
This prompted 2 questions: Is this normal and has anyone else checked their bullet length. This is for my bench rest gun, not my 30-30 plinker.
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The short ones had air bubbles in them. 
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I just finished bumping and seating gas checks all in one operation and going from a spire point to a flat nose these are 358 rifle bullets but they varied plus or minus 4 thous. but all looked the same from gas check to the nose.
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3X3X3 cube of steel.... we want a .050" chamfer on all corners;
Two ways to look,and process engineer this(and your OP). 1st,we pop it into the vise on a Bridgeport and go to town. The 2nd,or other way is to file it. The first method is high on tooling/equipment and within reason,low on skill(could even be CNC)..... plug N play if you will.
2nd method was very high on skill,low "tonnage" on equipment. Yes,you need a great file.
You've got to understand the difference in how that translates to your issue of length. Trying to diagnose "skill" or technique issues on a net based forum is gonna be tough..... well,compared to someone observing? Reckon you could take a vid. But hope you catch my drift.
To say,"you're not doing it right" or you haveta hold your mouth just so is a little(lot),short sighted. About as bad as saying "get an XY piece of equipment). It's up to each individual to understand where they want to draw the line.
I'd say.... assuming you have decent kit,there's something in your skillset that's causing the issue. If you consistently do something wrong,pull to hard... dwell too long,etc. the consistency "should" produce say,a bunch of crooked bullets but hey,they're all the same "bent".
If it's intermittent,or occasional then it's "probably" you introducing the error. How? Beats me.... just sayin,try to distinguish between skillset vs tooling/equipment.
Good luck with your project.
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Had to read this a couple times to understand, but yes, It probably is me.
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Are all of your bullets from the same cavity? Both cavities of a 2 cavity mold might not be the same length.
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Never checked that. I'll have to wait for the next casting session to check that out.
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Dan: Just cast up some new bullets and I found 2 discrepencies. How ever that is spelled. First of all my sprue plate was loose and that was leaving pimples on the bullet bases and so does whacking the sprue plate with a mallet. This is a 3 cavity mold and is almost at my arthritic limit to cut the sprues with my hands. The other thing is there is a .007 length difference between the cavities. Next I'll lube ,GC, and bump to see if results are more even. All bullets with sprue bumps went back in the pot.
I'm glad I have 2 '06s and a 30-30 that don't require this fussiness.
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wimilkman
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pat i.
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Tom Acheson
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MarkinEllensburg
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Aaron
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Ed Harris
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mashburn
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porthos
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MP1886
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linoww
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