Litz BC for Hornady ELDX

[Boe]

As a comparison and add to the confusion this data is from Hornady. It was also disclosed Hornady stopped using the 800 yd BC and now use the 200 yd BC for the ELD and the ELD-X
6.5mm 143 gr ELD-X
Mach 2.5:
0.623 G1
0.314 G7

Mach 2.0:
0.604 G1
0.303 G7

Mach 1.75:
0.584 G1
0.294 G7

 

[dfanonymous]

As a comparison and add to the confusion this data is from Hornady. It was also disclosed Hornady stopped using the 800 yd BC and now use the 200 yd BC for the ELD and the ELD-X
6.5mm 143 gr ELD-X
Mach 2.5:
0.623 G1
0.314 G7

Mach 2.0:
0.604 G1
0.303 G7

Mach 1.75:
0.584 G1
0.294 G7

It's not confusion. It's all correct. The BC is based on form factor and a standard velocity. It's anyones guess what the "standard" velocity is but they need to use a standard to give the BC of a bullet that is capable of going into short action and long action cartridges when selling just the projectile. For factory anmo, the BC is given for the cartridge/ projectile combo, obviously, and is based of the test barrel data.

Litz information is just corrected g7 profiles, but you'll notice on applied ballistics the other profiles that have the same grain and model projectile that are different. These are from the AB booth where they run radar for specific rifles. Because most data is like the hornady info above…averages over series of velocity spans, that doesn't always work with everyone's rig.

The correct way to choose a BC is to use ALL the BC's. All three mach speeds organized for dope in its respective category of range groups. However, you can circumvent that by using a custom drag model instead.

Sure you can just use one BC, and I'm sure the internet has "been doing it for years" and "is just at as good as," "never had a problem" etc.
To that crowd, you do you.

 

[Boe]

I guess I should have clarified, The confusion I was referring to is, When new shooters use a BC on the box most don't realize the BC changes throughout the bullets flight. Some ballistic programs do a good job accounting for these changes in the BC, Some not so much.

When the new shooters fail to true their BC and Velocity they don't understand why they don't get the results on paper they were expecting. As you can see this could be frustrating and confusing to the guy with limited experience.

The issue I had was, I just loaded a new lot of the 6.5mm 143gr ELD-X. I have had to correct my ballistic program from the data collected from the first boxes of 6.5mm 143gr. ELD-X I acquired a few years ago. Same load, same rifle, same velocity, same day shooting. Different impacts. I was assuming there were slight changes made in the profile of the bullets. Therefore different BCs

Apparently some changes were made that have been noticed by others, a previous post from Entoptics has measured differences when comparing new and older bullets. I guess the lesson here is verify on paper and don't assume everything is the same.

 

[dfanonymous]

You'll notice this article was published in 2018.

Hornady 143-grain ELD-X: Review & Hunting Performance Test

The Hornady ELD-X bullet is advertised as a technologically advanced, match accurate, all range hunting bullet. This review covers the 6.5MM 143-grain ELD-X, and focuses on how it performs as a hun…

panhandleprecision.com

The BC that was used is .314 in the article.
6.5mm 143gr. ELD-X.

Nothing significant has changed in form factor.

The only issue is people, new or old, not knowing what they don't know.

Like I said, three BCs, one for short range, mid range/long range and long range/elr. This is not a new thing. Using BCs now is retroactive for this reason.

 

[338 dude]

You'll notice this article was published in 2018.

Hornady 143-grain ELD-X: Review & Hunting Performance Test

The Hornady ELD-X bullet is advertised as a technologically advanced, match accurate, all range hunting bullet. This review covers the 6.5MM 143-grain ELD-X, and focuses on how it performs as a hun…

panhandleprecision.com

The BC that was used is .314 in the article.
6.5mm 143gr. ELD-X.

Nothing significant has changed in form factor.

The only issue is people, new or old, not knowing what they don't know.

Like I said, three BCs, one for short range, mid range/long range and long range/elr. This is not a new thing. Using BCs now is retroactive for this reason.

I use the Shooter ballistics app on my phone I run five BC's with it

 

[dfanonymous]

I use the Shooter ballistics app on my phone I run five BC's with itView attachment 290176

You shoot out to sub sonic?

 

[338 dude]

You shoot out to sub sonic?

No the farthest targets available to me is 1250 yards

 

[Boe]

You'll notice this article was published in 2018.

Hornady 143-grain ELD-X: Review & Hunting Performance Test

The Hornady ELD-X bullet is advertised as a technologically advanced, match accurate, all range hunting bullet. This review covers the 6.5MM 143-grain ELD-X, and focuses on how it performs as a hun…

panhandleprecision.com

The BC that was used is .314 in the article.
6.5mm 143gr. ELD-X.

Nothing significant has changed in form factor.

The only issue is people, new or old, not knowing what they don't know.

Like I said, three BCs, one for short range, mid range/long range and long range/elr. This is not a new thing. Using BCs now is retroactive.

I'm not arguing any of those points, I am well aware that. Obviously there is a difference as to why two lots bullets impact two distinct points of vertical impact throughout the course of fire. Course of fire being 773 yds to 1218 yds.

This was confirmed when the marked rounds were fired in random order. The shot impact became very predictable with each lot . The test ammo was loaded on site from the same 10 pcs of sorted, prepped and neck turned Norma brass. Neck chamber clearance on the loaded round is .0032. .002 neck tension on the custom full lenghth size bushing dies. ES on the load is 3fps on a 10 shot string. The rifle, I chambered in 6.5-284 Norma with a Borden Receiver, 30" 1.250 Kreiger. Night force NXS 8-32 and weighs 19.7 lbs and very little recoil . The rifle was shot on a SEB front rest and Edgewood rear bag. Conditions were good.

As you can see most of the variables were addressed as much as possible. A scientific test by no means. But, One might come to the conclusion that the only variant is the two different lots of projectiles. What is the exact difference? I don't know at this point. I don't really care, both lots group about the same. I am just curious as to why.

But to assume nothing has changed since 2018 is a rather reckless assumption . Bullet dies eventually wear out and have to be replaced. I remember shooting BR in the 1990s. Custom Bullet maker and BR Shooter Allie Euber had a great set of dies that made the best 6mm Bench rest bullets ever at the time. When the dies wore out and and were replaced his bullets were not the same. They were still good but not as the previous set of dies. I'm sure some of you old BR guys probably remember this too. On another occasion I had a premium bullet makers lot of bullets vary as much as .003 to .018 on the base to ogive measurement. All in the same box. These are just two examples.

It is a fact that there are more than one OAL of the 143gr. ELD-X. Where is the measured difference on the bullet profile? Base, Bearing surface, or forward of the bearing surface? Ballistic Calculators can't factor in unknown variants in the equations. Nor can they differentiate between bullet jackets that are 1and 2s or just 3s Some variants are only visible on the paper target.

You are right about one thing, People not knowing what they don't know. None of us know everything. Throughout my career I have been privileged to shoot with some of the best Shooters, Riflesmiths, Barrel makers, Action Makers, in the world. And through many conversations with them not a single one of these gentlemen thought they had it all figured out. Thats how problems are solved and new ideas come along. Point being, Verify everything before making assumptions, You may be the one that didn't know what you didn't know.

Regards,
Richard Hilts
Hilts Accuracy Custom Rifles
www.hiltscustomrifles.com

 

[dfanonymous]

The bc is the same then, as it is now. For the purposes of this conversation, before getting into a **** show over machine tooling, it is the same. If the bc is the same, the form factor is the same. It's a pretty good assumption.

There's more variation in barrel manufacturing tolerances and length that effect the bullet then in bullet manufacturing.