Hunting with a Marginally Stable Bullet

[General RE LEE]

I'm working up a load for a 175 grain .284 ELD-X in a 1:9 twist Brux barrel in my 7mm STW.

Berger site has it marginally stable at 1.38 at my altitude and hunting temps. Load is for deer 500 yards or less.

What are y'all's thoughts?

 

[vedauvoo]

I don't have any useful first-hand knowledge in this regard. I do know that Steve at Hammer Bullets really stresses bullet stability to maximize terminal performance for his line of bullets. I suspect the same is true for any hunting bullet.

Do you have any lighter options?

 

[Andrew Massi]

No
Marginally stable bullets don't perform like their stable counterparts
Also you own a cm that's quite accurate. Why in the world would you shoot whitetails under 500 with a 7 mag?

 

[NW NM hunter]

No idea on the stability or the 7stw, but in my 280ai out to 1000 ballistically the 162 eldx is very close due to the increased starting speed and may be more stable.

 

[HSmithTX]

I haven't checked the calculators, but I know a LOT of benchrest guys run hybrid 180 Bergers out of 284's with 8.5 twist at 1000 yards exceptionally well. Typically they will be 2825-2850ish with a straight 284 and 2925-2950ish with a modified 284, usually 28-30" barrels for both. It doesn't compute well for my brain that an STW with at least 150 fps more (300fps more is likely possible) than a modified 284 won't stabilize a 175 ELD-X with a 9 twist? Unless your STW is a short barrel or you are going to load it down below 7RM levels intentionally I would give it a try and see how it shoots. If it shoots good I would use it in a heartbeat. The ELD-X line from my experience is a very soft bullet and will fragment violently at high speeds, at STW speed inside 500 it should be a deer stomper.

As suggested, the 162 should fix your concern, I have shot them out beyond 1000 and accuracy has been excellent out of 8.5 and 8 twist barrels.

 

[Varmint Hunter]

A 175gr bullet put in the vitals of a whitetail at under 500yds sure won't need more stability to be fatal. Yeah, a 1.5 SF might get you better straight-line penetration, but no whitetail will know the difference.

Just my 2 cents

 

[HARPERC]

You'll likely be fine.

1) have you shot it at 500 yards?
2) at the very least you give up a little stability, and BC at the same time.
3) I don't know the Berger line up well, or availability, but suspect a somewhat lighter bullet would serve you at least as well.

Terminal Stability matters, but in your scenario not much.

 

[Hugnot]

Your 7mm ELDX will have more than adequate of a Sg for its intended use. This is not a marginally stable bullet for your specific use.

The Berger Sg calculator, that was used to come up with a Sg of 1.38, does not make allowances for plastic tipped bullets like the Hornady .284 ELDX. The plastic tips are regarded as having zero mass by the Miller Sg estimator that is used by JBM & others. The Berger Sg estimator will give low Sg values because the plastic tip is regarded has having the same mass as the entire bullet. When applying the bullet OAL to the Berger Sg estimator the Sg process assumes that the entire bullet does not have a plastic tip and the Miller Sg process used by JBM & others subtracts the plastic tip from the bullet OAL. This means no problem for your intended use - your 7mm 175 ELDM bullets will fly good with nice Sg's. Sg values will increase as range increases.

The Berger Sg calculator uses Hg pressures commonly found at certain altitudes and does not compensate for atmospheric conditions like high pressure "blue bird" days or stormy humid days. The Berger Sg calculator uses the common Miller Sg estimator but does not allow for atmospheric conditions that would affect pressure or plastic tips that are regarded as having no mass but are included in bullet OAL.

So:





The 7mmSTW sounds like some kind of cannon, I guessed it would shoot 175's at 3000 fps. If I had to shoot deers I would use my little 6mm CM. The 7mm STW sort of looks like a scaled down version of the US Navy 3 inch 50 or Germainian 88 - big guns for shooting hi altitude aircraft or armor fiercing.


The spread sheet contains 3 columns each having 3 different pressures or altitudes (sea level, 3000 ft, 5000 ft) & two rows of 35 & 45 temperatures. The math is shown at the top & the operation where plastic tip length (.142) is subtracted for OAL is shown (column & row).

The altitude & pressure chart provide pressures at certain altitudes.

Your use of the 7mm ELDX would be close to optimum for shooting deers up to 500 - good Sg, good terminal stuff, good wind & trajectory. Lots of effective smashing terminal stuff to kill the deers.

Use the Hornady 4DOF calculator instead of the Berger. The Hornady 4DOF indicates adequate stability for your application.

Ballistic Calculators - Hornady Manufacturing, Inc

Kestrel® 5700 Ballistics Weather Meter with Hornady® 4DOF® Combining complete onsite environmental measurements with the precise trajectory solutions of the integrated Hornady 4DOF® ballistics solver, this rugged all-in-one...

www.hornady.com

 

[General RE LEE]

Your 7mm ELDX will have more than adequate of a Sg for its intended use. This is not a marginally stable bullet for your specific use.

The Berger Sg calculator, that was used to come up with a Sg of 1.38, does not make allowances for plastic tipped bullets like the Hornady .284 ELDX. The plastic tips are regarded as having zero mass by the Miller Sg estimator that is used by JBM & others. The Berger Sg estimator will give low Sg values because the plastic tip is regarded has having the same mass as the entire bullet. When applying the bullet OAL to the Berger Sg estimator the Sg process assumes that the entire bullet does not have a plastic tip and the Miller Sg process used by JBM & others subtracts the plastic tip from the bullet OAL. This means no problem for your intended use - your 7mm 175 ELDM bullets will fly good with nice Sg's. Sg values will increase as range increases.

The Berger Sg calculator uses Hg pressures commonly found at certain altitudes and does not compensate for atmospheric conditions like high pressure "blue bird" days or stormy humid days. The Berger Sg calculator uses the common Miller Sg estimator but does not allow for atmospheric conditions that would affect pressure or plastic tips that are regarded as having no mass but are included in bullet OAL.

So:

View attachment 403241

View attachment 403242

The 7mmSTW sounds like some kind of cannon, I guessed it would shoot 175's at 3000 fps. If I had to shoot deers I would use my little 6mm CM. The 7mm STW sort of looks like a scaled down version of the US Navy 3 inch 50 or Germainian 88 - big guns for shooting hi altitude aircraft or armor fiercing.


The spread sheet contains 3 columns each having 3 different pressures or altitudes (sea level, 3000 ft, 5000 ft) & two rows of 35 & 45 temperatures. The math is shown at the top & the operation where plastic tip length (.142) is subtracted for OAL is shown (column & row).

The altitude & pressure chart provide pressures at certain altitudes.

Your use of the 7mm ELDX would be close to optimum for shooting deers up to 500 - good Sg, good terminal stuff, good wind & trajectory. Lots of effective smashing terminal stuff to kill the deers.

Use the Hornady 4DOF calculator instead of the Berger. The Hornady 4DOF indicates adequate stability for your application.

Ballistic Calculators - Hornady Manufacturing, Inc

Kestrel® 5700 Ballistics Weather Meter with Hornady® 4DOF® Combining complete onsite environmental measurements with the precise trajectory solutions of the integrated Hornady 4DOF® ballistics solver, this rugged all-in-one...

www.hornady.com

Man, that was an epic post. Thank you!

 

[skipglo]

I'm working up a load for a 175 grain .284 ELD-X in a 1:9 twist Brux barrel in my 7mm STW.

Berger site has it marginally stable at 1.38 at my altitude and hunting temps. Load is for deer 500 yards or less.

What are y'all's thoughts?

Maybe it's just cause Berger doesn't like Hornady...you think?

 

[Hugnot]

^^ Maybe, Berger does not like plastic tipped bullets. ^^

Cut off the plastic tip which will shorten the bullet & run the Sg numbers again using the Berger Sg & see the Sg increase. The plastic tip for the 175 ELDX is about the same length as tips on other ELDX bullets -- .14 inches. The Miller Sg estimate process treats the plastic tip as weightless, but Berger makes no allowance for plastic tips like JBM Sg does. Both Berger & JBM use the Miller Sg process.

 

[blackburbot]

As mentioned before, if you have done load development and didn't have issues with grouping, especially if you plan under 500 yard shots and did some practice shots at that distance to verify results and the holes were circular not some other funky shape you will be golden.... until buck fever hits and 20yard shots are missed ...yes it happens to 99.93% if everyone.

I'm also caught up in the whole world of chasing number game. But slowly realizing that most of the numbers that people are worried about will have no effect on what really happens in the real world. People are getting too worried about short distances and optimum performance and what is deemed stable and best in class ...

I personally missed more shots consistently now that I have all the fancy gear that tells me how everything is going to theoretically work than when I just had a box of bullets and went practicing. We get caught up relying on technology to tell us how to shoot than relying on our own instincts on how to shoot. We get complacent on how to do stuff rather than actually doing it

 

[lancetkenyon]

Go shoot it at 500+ and see how it does.

 

[nralifer]

I'm working up a load for a 175 grain .284 ELD-X in a 1:9 twist Brux barrel in my 7mm STW.

Berger site has it marginally stable at 1.38 at my altitude and hunting temps. Load is for deer 500 yards or less.

What are y'all's thoughts?

Never a good idea to hunt with marginally stable bullets. Hunting demands excellent terminal performance, and you never know what the conditions are going to be at the time of the shot. Benchrest shooting demands only accurate bullet placement but terminal performance is irrelevant when you are hitting steel targets. At close range with a high speed fragile lead core bullet increases the chances of poor penetration and an injured animal.