Bullet length and COL

[deadwooddick]

Take 4 bullets; from tip to base, in inches…

[list type=decimal][*].302
[*].310
[*].315
[*].325[/list]
Taking the two extremes, the .302 & .325 bullets AND seating in sized cases, both w/ the same case length and neck tension (.002")… I end up with different base to tip dimensions.

First case (.302 bullet) is 2.971" C.O.A.L.
Second case (.325 bullet) is 2.987" C.O.A.L.

How do you achieve accurate loads, when you "lose" .006" in C.O.A.L. with a bullet length difference of .023" and the seating depth change is "just" .016" ?

There sure ain't NO consistency.

 

[bulletdrop]

Are these the same brand bullets? What bullets are they?

Either which way, most seating dies seat to the ogive of the bullet, not the tip. Two bullets compared side-by-side can have lengths of 'ogive-to-tip' that are different than their 'base-to-tip'.

 

[Alex Wheeler]

You have to sort them. I have had good luck sorting base to ogive. If you aren't trimming and pointinging you can also sort base to tip.

 

['Freak]

Per mostly my readings, if you were to check the same bullets using your comparator you will likely find there is a lot less difference measuring base to where abouts the ogive contacts in the comparator and meaning the majority of the length difference will be found between the ogive and the tip.

 

[deadwooddick]

Thanks for the replies.

1)All same lot, 140 SMK

2) if tip to ogive dimension is variable, how can a die that seats from a point between the ogive and the tip, produce ammunition that's consistent ?

3)Sorting… did a random sample of 50 (out of 500) and found 12 "outliers" e.g. those longer/shorter than the remainder.

If standard holds true, out of 500, 120 will be "unusable" for long range since they'd compose two different "lots" of 60± where the requirement is 100 for the event.

Anybody wanna' buy some "short" or "long" 140 SMKs ? :