Berger Ogive variance

[Dusty Stevens]

Manufacturers run the bullet forming dies until they are worn enough to replace. The next new die may not be machined 100% exactly the same so there are bound to be some variance between lots. For instance these are the same part number Hornady bullets in 2 different lots measured with a Hornady comparator on a dial caliper. No matter how you seat these, you won't get the same results. I always seat using the comparator (.010" smaller than the bullet diameter) to get a similar jump. This would still add or reduce the depth if the bullet in the neck/case by .036" slightly changing the case volume. Seating from the tip would effect the jump by .021", bad if you seat them close to the lands.
View attachment 1116816

Those could be from the same box

 

[Raythemanroe]

It would be nice if they didn't mix runs from different forming dies.. Box should say Lot #B Die #7..lol


Ray

 

[T-shooter]

Those could be from the same box

There could be that much difference. With the ones I measured, I went through maybe 15-20 out of a box of 100 and picked the longest and shortest overall.
Here are 2 of a Hornady .223 75g from the same box. I did not check them all so there were probably some worse. I have seen Hornady, Berger, and Sierra bullets as much as .0003" out of round.

 

[Dusty Stevens]

Heres one i keep dragging back out. You dont even need calipers to sort this box

 

[Lbart]

View attachment 1116880

Heres one i keep dragging back out. You dont even need calipers to sort this box

Definitely not Bergers!

 

[Bc'z]

View attachment 1116880

Heres one i keep dragging back out. You dont even need calipers to sort this box

They're making a sine wave.

 

[JFrank]

View attachment 1116880

Heres one i keep dragging back out. You dont even need calipers to sort this box

Do they weigh the same?
That’s all ya need for a Creedmoor

 

[Nature Boy]

Do they weigh the same?
That’s all ya need for a Creedmoor

Hell, if it’s a creed you could load a rock in it and win a match

 

[338 dude]

Question for F class and Benchrest guys. Think I know answer but want to confirm.

I'm loading now for a 1,000 yard F class match. I had some rounds left over from last match where the rifle shot fantastic and compared to current batch of bullets. Current batch of 200g Berger Hybrids is -.005" shorter ogive than last batch. The barrel is jump sensitive and I know where it likes for best grouping and typically load to to a set COAL (based on ogive).

I don't have any available time to go testing as I would normally do before this match. I can measure the CBTO and figured I would just seat the new bullets to same CBTO as last batch regardless of the COAL. I already measured one and it would not be jammed, just .005" longer on COAL.

Thoughts?

I think it depends on how deep you want to go you have a bullet with two ends the Ogive distance to lands is very important the other end dictates final case capacity of combustion chamber if you really get down to it both could possibly make a difference In a perfect world I would buy enough bullets of the same lot to burn out a barrel

 

[okie]

View attachment 1116880

Heres one i keep dragging back out. You dont even need calipers to sort this box

dang!!--what are those?

 

[Delfuego]

dang!!--what are those?

Those are Hornady "Match" Bullets

 

[cw308]

I'm shooting Sierra MK , every lot change I have to tweak alittle to get the same CBTO measurement . As 338 posted when the bullet position is further in or out of the case things change . From that first CBTO setting that was just perfect , keeping that setting with changes in bullet shape did anyone tweak the powder charge or wasn't it necessary .

 

[okie]

Those are Hornady "Match" Bullets

HMMM...