Bullet lot numbers and seating depth

[Bayourambler]

I just wanted to check in and see how different folks treat reloading when a new box of bullets are opened with a different lot number. I usually load the new box using a bullet comparator for bullet seating depth. I ignore the COAL, because I find bullet jump to play a bigger role than the little differences case capacity. What do you do?

 

[Blue68f100]

That's the way I do it. I have found as much as 0.010" in OAL between batches and have the same comparator/reference number.

 

[243winxb]

Every component is assigned a lot number. Loaded with same COAL. Test fired on target.

If result are bad, i know where to look.

Seen the same Sierra # 1530 go fron 3/4" to 3" using a different lot number.

 

[RAT807]

I measure the bullet ogive length and depending on how wide the various measurements are, I sort in groups of .002 - .003. Ex. I have a 500 count box of Hornady 115gr HAP that the ogives vary from .266-.271. I load these bullets with accuracy in mind so a small variation in ogive length is my goal.

I also have a load with copper plated bullets that have a much wider ogive variation. I group these in .003 variations.

 

[Stew0576]

Silly question, if they are all seated to the same OAL won't they shoot the same? Is .003 less space in the case making that big of a difference?

 

[Blue68f100]

Yes it can.. if you shooting for BE accuracy.

 

[Walkalong]

Is .003 less space in the case making that big of a difference?

Doubtful.

 

[Conniption]

As with so many things done at the loading bench the answer is... It depends.
If your shooting is primarily 300 yards or less with an off the rack hunting rifle, then Walkalong pretty much nailed it.
However, if your aspirations are 1500 yards away and you've just sunk the kids 1st semester collage fund into a bench rifle then .003" may be a bit on the lenient side and you may want to tighten that up to +- .0005"!

 

[Bayourambler]

Silly question, if they are all seated to the same OAL won't they shoot the same? Is .003 less space in the case making that big of a difference?

Well im thinking that bullet differences can cause different bullet jump, if you use overall cartridge length, and not a bullet comparator. Like I said, bullet jump is way more important than those tiny case capacity differences... as we said before, different lot number on boxes of bullets will measure out different most of the time.

 

[Walkalong]

It's what is more important where the ogive is located and how consistent that is, IMHO.

If you and your rifle can shoot the difference between your standard and bullets seated .003 deeper, I'll be very impressed.

 

[hdwhit]

Bayourambler asked:
What do you do?

Nothing.

When I got my first micrometer, I went bananas measuring everything. In time that became passe and I stopped. But, in the meantime I found variations within each box of bullets comparable to the variations between boxes.

I've been loading Hornady 60 grain Spire Point bullets since 1980 and while I have noticed some slight changes in the bullets over the years, the ones I load today perform the same (out to the ~200 yards that I shoot) as rounds loaded in the early 1980s that I still have and use as a baseline for the load.