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.025 difference box to box

boltfluter

boltfluter

Just comparing one lot of Berger 105 VLD to the next lot I am about to load. Holy hell, what is going on! Quite shocked to say the least. The most change I have ever seen with any brand! This is a comparator reading. Right at .025 difference with the new lot. New lot is longer than previous lot. Talk about a great way to screw up seating depth if you don't check! :D:D:eek:

Paul
 
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Don't mean to hijack this thread but what is an acceptable delta (Base to Ogive). I am preparing to measure and would like to know how to group.
 
boltfluter said:
Just comparing one lot of Berger 105 VLD to the next lot I am about to load. Holy hell, what is going on! Quite shocked to say the least. The most change I have ever seen with any brand! This is a comparator reading. .025 difference. Talk about a great way to screw up seating depth if you don't check! :D:D:eek:

Paul
Click to expand...

While the difference is alarmingly large, presuming the two LOTs were pointed via the same die, the actual "seating depth" (bolt-face to ogive) could be the same, with only the depth of intrusion into the case-necks being different.:D

While B-O is a measure of both LOT to LOT, and within a LOT uniformity, to assure that nothing is broken, or, loose, so long as the bullets are pointed in a single die, B-O has little bearing on, "seating depth": the seater-stem will contact a point on the nose, and "seating depth" will be established from that point, to the tangent point of the bullets shank & nose - the base will merely, "Yo-Yo" up/down the neck, while the distance from the ogive to the case-head/bolt-face will be the same.;)

If you seat some bullets [into cases] and observe varying differences in case-head to Ogive, the bullets may be coming from multiple dies - that is not so good, and may affect "seating depth", as the nose radius may vary somewhat from die-to-die.:eek:

Had a guy in the shop last week, and demonstrated this to him: used a 187 Gr., 10 ogive FB (1.300" long jacket) and a 118 Gr. 10 ogive FB (1.00" long jacket): difference in B-O about 0.300"!:eek: Seated in the same case the the case-head to ogive difference:0.001".;) The secret: same point die.:)RG
 
boltfluter said:
Just comparing one lot of Berger 105 VLD to the next lot I am about to load. Holy hell, what is going on! Quite shocked to say the least. The most change I have ever seen with any brand! This is a comparator reading. Right at .025 difference with the new lot. New lot is longer than previous lot. Talk about a great way to screw up seating depth if you don't check! :D:D:eek:

Paul
Click to expand...

Paul,
These are the dimensions we hold in a LOT of bullets:
The points below are both factual tolerances and dimensions, or policies and procedures that we use to ensure our highest quality reputation.

We use only the highest quality copper and lead available to eliminate impurities or other material issues. Our material vendors have been in their industry for decades. We have regular meetings at their facility and ours to refresh our mutual understanding of our highest material quality requirements.

Our bullet weight tolerances are listed below. The actual results are usually tighter than these tolerances allow:

  • 17 Cal to 30 Cal: +/- 0.2 gr
  • 338 Cal: +/- 0.3 gr


Our bullet base to ogive tolerances are listed below. It is important to note that measuring this dimension is difficult as the point of contact is a thin and rounded surface. If you find measurements greater than the tolerances listed below please measure the same 10 bullets several times to confirm that your measuring device is reliable and repeatable (many on the market are not). We use a specially developed process which includes custom made gauges to ensure reliable and repeatable measurements. Most reports of bullets outside this tolerance are found to be the result of how they are measured:

  • 20 gr to 115 gr: 0.003 ES
  • 120 gr to 210 gr: 0.005 ES


All jackets, cores and bullets within a given lot are made with one die to guarantee consistency.

Each bullet is made on a die that is designated for that bullet. This die is set aside and used again for all lots until this one die wears out.

All tooling is precision made using dimensional tolerances in the .00005. Using precision-made tooling is an absolute requirement. The companies who make our tooling are specifically in the precision tooling business. We meet with them regularly to communicate our tooling needs and special projects. Those who understand precision tool making know that these things are possible but not without deliberate effort and experience.

J4 Precision Jackets are the only bullet jackets in the world known for less than .0003 total wall thickness variation on every size and lot.
Seat a bullet from each lot DO NOT ADJUST THE BULLET SEATER! Unless you do not have a VLD bullet seating stem and the tip of the bullet from one of the lots is bottoming out in the seater stem cavity. You will probably find the CBTO of both cartridges is the same or very, very, close I recently did a test on this involving 3 different lots of BERGER 6.5 130gr VLD bullets. A check of the lot numbers showed production of each lot was on average 2 years apart. The bullet base to ogives were checked. One lot showed 0.6200 , one 0.6750 and one 0.6525. When these were seated the CBTOs were : 2.070 , 2.0705 and 2.0695 so plus or minus .0005 using the 2.070 as the mean. So please check your CBTO measurements. When you change bullet lots I suggest that you drop the powder charge back 1 to 1 1/2 grains (just like you would if you were changing powder lots) an work the charge back up slowly checking for pressure signs and accuracy to find the velocity accuracy node. The fact that there MAY be more or less of the bullet down in the cartridge case between the lots can effect pressures /velocity. In my case one lot had a lower velocity (2630 FPS AVG) and an SD of 11. Another had a higher velocity (2649 FPS AVG) and had an SD of 11.1. The load that was used as the accuracy control load was 2635 FPS on average with an SD OF 4.3.
Hope this helps. If you have any questions please feel free to contact me here or at the phone number below. By the way the cartridge was the 6.5x47 LAPUA.
 
boltfluter said:
Just comparing one lot of Berger 105 VLD to the next lot I am about to load. Holy hell, what is going on! Quite shocked to say the least. The most change I have ever seen with any brand! This is a comparator reading. Right at .025 difference with the new lot. New lot is longer than previous lot. Talk about a great way to screw up seating depth if you don't check! :D:D:eek:

Paul
Click to expand...
That doesn't mean the seating depth will be that much different. I measure bullets from pressure ring to ogive and have seen way more then .025 differences. Matt
 
Just an FYI. The bullet comparator that I use is one that I made from a left over piece of the original barrel. Cut with the actual reamer used to cut the chamber. So, the comparator is a mirror image of the chamber. Eliminates most variables associated with a generic store bought bullet comparator. Kind of takes us right back to the bullets to my way of thinking. I will seat a few of the new lot, with same setting on the Wilson seater, and see what I come up with.;)

Paul
 
boltfluter said:
Just an FYI. The bullet comparator that I use is one that I made from a left over piece of the original barrel. Cut with the actual reamer used to cut the chamber. So, the comparator is a mirror image of the chamber. Eliminates most variables associated with a generic store bought bullet comparator. Kind of takes us right back to the bullets to my way of thinking. I will seat a few of the new lot, with same setting on the Wilson seater, and see what I come up with.;)

Paul
Click to expand...

Paul - at one point I encountered a Lot of 185 Juggernauts that were more like .050" longer on average than the previous Lot # I had (bullet OAL). I had been shooting the previous batch of 185s out of a rifle with a relatively short freebore using H4895. The extra length of the new Lot of bullets combined with the short freebore was the straw that broke the camel's back. The issue was not seating depth, it was pressure. I went back to Varget with that Lot of Jugs, adjusted the load accordingly, and they worked just fine.
 
I just sorted 5 boxes of 105 hybrids and I had a .005 spread across all 5. They aren’t from the same lot. But one of those bullets is .03 short. That’s really weird
 
RGRobinett said:
While the difference is alarmingly large, presuming the two LOTs were pointed via the same die, the actual "seating depth" (bolt-face to ogive) could be the same, with only the depth of intrusion into the case-necks being different.:D

While B-O is a measure of both LOT to LOT, and within a LOT uniformity, to assure that nothing is broken, or, loose, so long as the bullets are pointed in a single die, B-O has little bearing on, "seating depth": the seater-stem will contact a point on the nose, and "seating depth" will be established from that point, to the tangent point of the bullets shank & nose - the base will merely, "Yo-Yo" up/down the neck, while the distance from the ogive to the case-head/bolt-face will be the same.;)

If you seat some bullets [into cases] and observe varying differences in case-head to Ogive, the bullets may be coming from multiple dies - that is not so good, and may affect "seating depth", as the nose radius may vary somewhat from die-to-die.:eek:

Had a guy in the shop last week, and demonstrated this to him: used a 187 Gr., 10 ogive FB (1.300" long jacket) and a 118 Gr. 10 ogive FB (1.00" long jacket): difference in B-O about 0.300"!:eek: Seated in the same case the the case-head to ogive difference:0.001".;) The secret: same point die.:)RG
Click to expand...


Thanx Randy... you de man.
 
1shot said:
What bullet and how long ago if I may ask?
Thanks,

Lloyd
Click to expand...
Lloyd
These are Sierras 107. So I am almost out of Bullets leading to digging through my stash for an event for this " Weekend "

100 box- BBTO.687 ( half)
100box - BBTO.685 (half)
500 box- BBTO.677 (now empty )
I called a friend his measured
BBTO- .648
.687
- .648
= .039 :(
 
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