73 ELD Lot Variation

[flyingbrass]

I've used several lots of Hornady 73 grain ELD bullets. Until today, they all seemed very consistent. I've spent quite a bit of time and effort working up a good load with them for my AR-15 and getting things right in the Hornady 4DOF app.

I have 4 boxes of bullets from a new lot. When I went to seat the new bullets today using the same die setting, CBTO was about .006" shorter than normal. I have 4 bullets remaining from a previous lot, so I compared.

New is lot #2182247
Old is lot #2181778

Bullet length base to ogive (Hornady comparator):
New: .582" - .583" (~ .021" shorter)
Old: .603" - .604"

Bullet overall length:
New: 1.036" avg. (~.012" shorter)
Old: 1.048" avg.

The bases of the new lot are noticeably larger. The bearing surface is also obviously longer. All bullets weigh 73 grains plus or minus a tenth or so.

New on left, old on right:






I expect minor amounts of variation, but this strikes me as too much. I called Hornady. The tech didn't say much other than lots vary. He said shoot them -- that I probably won't notice any difference on paper. I bet there will be differences in pressure/velocity (longer bearing surface) and drop (different profile and base shape).

How much variation do you encounter between lots of rifle bullets? Until today I've been impressed with how consistent these had been.

 

[Zero333]

Looking at the pictures... It looks like they re-designed the bullet. Not a bad thing if it shoots as good or better.

Don't overthink it. The target is the most important judge. Let the targets speak for themselves.

 

[flyingbrass]

It's a bad thing since I was almost done fine tuning settings in the Hornady 4DOF app and testing at different ranges. I don't think the changes to these bullets were intentional. I doubt the drag coefficient is the same. They look like different bullets.

Initial testing with bullets seated to my previous CBTO showed muzzle velocity to be close to the same. However, in the rounds fired so far, velocity losses at 50 yards seem to be far less consistent with the new lot. I just started keeping track of this, so I don't have older data to compare.

Point of impact with the new lot shifted about .7" high and .7" left at 100 yards. This was the same for several groups. I shot a control group using the last of my earlier lot, and they were dead on. Precision so far seems close to the same, but I don't know yet. There were some outliers that could have been my fault. Needs more testing, and I may need to make some adjustments. Yesterday was too windy to shoot at longer ranges.

I've seen Hornady ad blurbs boasting about the lot-to-lot consistency of these bullets. If by luck you get the right lots, as apparently I had before, that is true. But at least on occasion there are pretty drastic differences.