Time to make the donuts....
- Thread starter AlNyhus
- Start date
jackieschmidt
Gold $$ Contributor
Dave, once you point up a bullet in a precision die, the outside be will perfectly round and shaped according to the dies profile.
However, this in no way tells you if the core is actually in the middle of the finished bullet. That is determined solely on the difference of the original jackets wall thickness variation. I touched on this in post #336.
You can have a bullet that is perfect in every way externally but be a mess on the inside.
The Vern Juenke (sp) machine was said to aid in determining how good, or bad, the internal structure was on an individual finished bullet. As to whether it actually did has always been a topic of discussion.
Which were the old legendary Eubers?
Just wondering if anyone can recall which die, weight & lot # were the legendary Eubers?
Dave- I pretty much only shoot flat base bullets (not always) and most 6MM bullets with a flat base generally measure .2433 to .2434, and my reamer was .2434- so really no clearance with regards to freebore diameter. About 2 years ago I went to lunch with Geotge U and discussed this with him and he recommended I get a reamer with .2440 freebore diameter. I had a new reamer made a few months ago with that .2440 diameter.
jcarpen
Silver $$ Contributor
Dave-I had a little trouble with this too. Had to go back and re-read Randy’s post on this.
Roundness (TIR) is measured on the outside diameter of the bullet. A BULLET spinner will check roundness.
Concentricity as commonly used in bullet making jargon is a measure of the difference in thickness of the walls of the jacket itself. This can be measured with a JACKET spinner or a good tenth ball mic.(visualize two perfectly round circles having a slightly different axis. They are round but not concentric.
It’s like a truck tire being unbalanced. They put weights on the rim to balance it out, but with a bullet spinning way faster, well everyone knows.
Mulligan
Silver $$ Contributor
Dave,
Yes in my post I referred to a bullet spinner checking the outside of a finished bullet for concentricity.
What I found was my core-seating process was wonky.
When I make long 6's, I pre-form the jackets in a separate step using different punches with a different adjustment on my core-seat die. After I pre-form a bunch, I readjust the core-seat die and swap punches.
I was using two lockrings and shims to help "keep my place" to where the die should be set for each operation. In the end, I was making crooked bullets because my core-seating die was on a bind in the press due to "redneck engineering".
Not all lock rings are flat!
Clay
and that says it all right there, the bullet that stabilizes the quickest will be less affected by the wind
Dave, Bullet spinners check the relationship of how square the base is to the body, its not checking cylindricity
spun many on a conventional spinner they had horrible run out over .001
Lot #58 were the magic ones 68 gr and by the way they were on sierra jackets
Jackie, You are over thinking that whole thing jacket concentricity is nice but not really what makes great jackets. I have had had hall of fame shooters do a blind test with .0007- .0008 tir jackets with .0001 jackets and d the funny part with three different shooters they all said they really close but the "lot B " bullets shoot a little bit better. They were the ones with .0007 tir...next I'm not a big bullet spinner kind of guy BUT its really usefull for setting dies actually I would consider crucial....
A 6mm bullet leaving the muzzle at 3000fps in an 1-8 twist barrel is rotating over 100 revolutions per second. Argue with me that an unbalanced bullet doesn’t matter. Testing is quite difficult, mother nature has the ultimate say. And it is quite rare to find uniform conditions for testing. If a jacket is larger on one side it obviously weighs heavier on one side. The cores are all uniform if weighed. There is no discrepancies in weight from side to side. I have gotten out of the process of making bullets, just some insight to what I have learned. Keep in mind I was making BT match bullets, completely different than FB Bullets.
Ok....and not arguing, but a serious question....So, what is better, a say 14 twist or say a 12 twist...all else equal?
Lets not forget that the bc may be increased by a bullet that is NOT marginally stable. It's perfectly ok to say that you have NOT tested both ways, but I have. My conclusion is that a little too fast is GOOD...not bad. Too slow is always bad. Again, from testing as well as a national championship...fwiw Which stabilizes faster? One that may never be stable or one that is stable when it leaves the muzzle? Serious question...
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Thank you George. It’s not an easy path to follow. My advice is to let those who have quality dies and have figured out the process make them for you. SOO much cheaper in the long run.
D Coots
Silver $$ Contributor
Thanks George. .
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