ELD-X ogive drastic difference

[Schanen51]

Good morning TFL! I was at the loading bench last night finishing up what 7mm mag brass I had shot recently. The bullet I'm using is the 162gr ELD-X. I've been through about 300 or so of them, and my rifle really seems to like them. I DO use a hornady comparator to measure seating depth when loading, and I check every round. Last night I finished one box of bullets and opened up another (different lot numbers). The comparator measurement was so far off, that I need second opinions here. Pictures included.

CBTO on the first box (we'll call that box A) was 2.707. This is what I developed the load with, and is .035" off the lands.

CBTO on the next box (we'll call that box B) was 2.740. That's quite a large jump.

Initially, I thought maybe my seating stem had backed itself out somehow, but everything was tight. That led me to checking the bullets out in a little bit more detail. None of these are factory seconds. I generally do not measure every bullet prior to use (though that might be changing shortly), and that's mostly worked for me over the past 17 years or so. Anyway, the bullets out of box B were significantly fatter and less tapered than the bullets out of box A (see pictures). Enough to change where the comparator measures the ogive .033". Now, in my rifle that's still not touching the lands, but that could be real issues with folks who load these babies close to the rifling.

Onto accuracy, obviously this is going to affect accuracy, but the question is how much. I find it hard to believe that the BC between the two bullets are very close at all. I loaded up 3 rounds, and I'll test fire them and report back with the changes. I THINK what I'm going to do, let me know if you agree, is back the powder charge down .5-1.0 gr and do some fine tuning of the load with the bullets seated back at .035" off the lands. I hate to say it, but I'm starting to develop trust issues with hornady bullets! That brings me to my next concern... if this happens continuously, and you have a match coming up, or a big hunt coming up, you better factor in significantly more time to load your ammo if you're going to have to retune the load everytime your lot number changes. It kind of sucks that long gone are the days of reloading your secret recipe in bulk.

EDIT: I'll get some BTO, length, and possibly bearing surface measurements for the bullets if anyone cares about that! I'll pull one of the old bullets tonight as well, so we can compare. FWIW, the OAL was the exact same

[ligonierbill]

I'd be contacting Hornady. Their 178 gr 0.308 is my go-to in 300 H&H. Maybe I need to take a look at my supply.

[georgehwbush]

just noticing the lot numbers, they had ran 10k lots between those two,
that may just be ware and tare on their equipment. i would NOT expect that much, but you need to contact hornady and see what they say. they may have even adjusted the ogive to improve stability or something...

[lugerstew]

I have seen .030 or more difference in ogive positions on same bullets but different lot numbers, I, like you got concerned that it could be a problem, so I called Sierra and asked why, and all he told me was that it was obvious I don't know much about bullet making and to just deal with it.
I agree, with that much difference it might be wise to do another load workup.

[Rimfire5]

I'd be interested to see the results you got when shooting them.

I've been measuring all my groups for years and years.
I have detailed records of jump & OAL for 5-round groups for at least 4 calibers - unfortunately, none with a 7mm.

In my results, I have seen some change in accuracy with changes in jump, but the changes are not really that significant so, unless your average groups are on the order of 0.400 inches and the standard deviation of your group measurements is less than 0.060 inches, you probably won't notice a difference.

[Schanen51]

Here's some numbers for you bean counters out there:

Box A: sample of 1 (I didn't feel like pulling my good, accurate ammo!)
- BTO: 0.770"
- Total length: 1.475"
- Weight: 162.0gr

Box B: sample of 10
- BTO: 0.809"
- Total length: 1.476"
- Weight: 161.93gr

Box C: sample of 10 (another box from another lot; same bullet)
- BTO: 0.810"
- Total length: 1.477"
- Weight: 161.97gr
- FWIW the lot number is 2231660, so much closer to the lot number of Box B than Box A.

Distance to the lands using bullets from Box B: 2.744" which puts the CBTO of 2.740 only 4 thou off the lands. I suppose safe, but ill follow up after I have a chance to shoot it again.

[Schanen51]

Originally Posted by ligonierbill

I'd be contacting Hornady. Their 178 gr 0.308 is my go-to in 300 H&H. Maybe I need to take a look at my supply.

Maybe check your lot numbers? It seems as though georgehwbush is right in that hornady must have intentionally changed something in their design

[Schanen51]

Originally Posted by georgehwbush

just noticing the lot numbers, they had ran 10k lots between those two,
that may just be ware and tare on their equipment. i would NOT expect that much, but you need to contact hornady and see what they say. they may have even adjusted the ogive to improve stability or something...

I think you're onto something. It seems intentional. I'll try and find some time to call them, but I'm semi worried that I'm going to get the same response that lugerstew got...

[Schanen51]

Originally Posted by lugerstew

I have seen .030 or more difference in ogive positions on same bullets but different lot numbers, I, like you got concerned that it could be a problem, so I called Sierra and asked why, and all he told me was that it was obvious I don't know much about bullet making and to just deal with it.
I agree, with that much difference it might be wise to do another load workup.

Not sure how willing I'd be to give that company my business again if that's the way their CS acts. He'd be right though, I'm not an expert on making bullets, which is precisely the reason I'm calling him lol.

[Schanen51]

Originally Posted by Rimfire5

I'd be interested to see the results you got when shooting them.

I've been measuring all my groups for years and years.
I have detailed records of jump & OAL for 5-round groups for at least 4 calibers - unfortunately, none with a 7mm.

In my results, I have seen some change in accuracy with changes in jump, but the changes are not really that significant so, unless your average groups are on the order of 0.400 inches and the standard deviation of your group measurements is less than 0.060 inches, you probably won't notice a difference.

I'll shoot a few groups and report back with measurements and pictures provided they function ok in my pea shooter

[zeke]

Ime, Hornady has been occasionally changing their bullet profiles over the years. In rifles and pistols, it has been from the gradual smoothed profile to the angled that you have documented. One of my favorite 22 bullets went this way years ago (50 gn v-max), and accuracy was significantly affected (negatively) even when the new ones were loaded in accordance with their new profile. Imo, it certainly is intentional and way beyond the minor occasional variances seen in other brands.

[cdoc42]

More years ago than I can recall, I opened a box of Hornady .277, 150gr bullets, and immediately noticed - without measuring - the cannelure on the "new" box was in a different position. I emailed Hornady but never received a reply, just to advise caution and to note somewhere on the box that this difference is present. It may have been a change designed to change the bullet expansion characteristics, and perhaps little to no concern to the handloader who seats bullets based on the base to "ogive," but neophytes in this hobby may well not recognize the difference if they simply seat to the cannelure to mimic factory rounds until they mature in the hobby.

[Schanen51]

Alright folks, straight from the horses mouth! I reached out to hornady and referenced the lot numbers and BTO difference in my bullets and they got back to me this morning.

"We changed the shape slightly and made it more consistent as a whole in accuracy around the end of 2022.

Hornady/SnapSafe Tech team"

There you have it, confirmed intentional. Maybe they sent a notice out to people, maybe they didn't. Either way, I suppose the positive side is that you won't have to worry about the bullets changing that drastically lot to lot?

I'll still report back with accuracy testing as it sits. Just need to find the time!

[Unclenick]

That much change will have a small effect in that the stubbier design will be pushed deeper into the case by a fixed seating stem. That will cause a small pressure rise. It will change bullet jump to the throat, as well, which affects accuracy, so you may be in for some retuning of your load, though you also may not.

The longer bearing surface and shorter ogive, unless the boattail was changed, too, would have greater volume, so they may be leaving a bigger hollow for the plastic tip. This would reduce the transverse moment of inertia of the bullet, making it a little easier to stabilize, so a little less twist could be used (in theory, but I'd have to measure the transverse moment of inertia to tell how much difference it makes).

The sharper shoulder indicates the ogive is a secant ogive on the new shape. Secant ogives generally have a longer ogive radius, giving them lower drag for a given ogive length than the older tangent ogive does, so it is possible the BC is unchanged.