impact velocity better or worse?

[huntsd]

I've been going down the rabbit hole on small calibers and impact velocity.

Say I am shooting a bullet that needs a minimum impact velocity of 1800 fps. For argument sake lets say an eldx. My impact velocity at 400 yard is 2300 fps and my impact velocity at 600 yards is 1900 fps. Will the bullet "work" better at 400 yards compared to 600 yards since the impact velocity is higher at 400? Or is performance expected to be the same at both 400 and 600 yards since both are above the minimum fps needed . @Formidilosus

 

[Johnwell]

Depends on the bullet, but typically the ‘minimum’ expansion speed results in a pretty minimal mushroom compared to a higher impact velocity. I personally don’t like to be on that edge.

 

[huntsd]

Depends on the bullet, but typically the ‘minimum’ expansion speed results in a pretty minimal mushroom compared to a higher impact velocity. I personally don’t like to be on that edge.

Thanks lets use eldx for now. tho i think the idea applies to many bullets.

 

[SDHNTR]

Yes. More speed = better function/more expansion. Generally speaking.

 

[hereinaz]

Generally:

Higher speed more fragmentation
Slower speed less fragmentation

It’s a bit counter intuitive, but at highest speed, you get maximum fragmentation so it’s less likely to exit. Larger circumference wound channel.

As speeds slow down you still get good fragmentation with smaller circumference wound channel, and more likely to exit because pieces are larger and have more mass.

That also depends on whether it hits bone or not. Thickness of the animal, etc

There is a Hornady podcast where they talk about no exits up close and then getting exits farther, while shooting 22 creed and 22 arc.

They stick with the “we like to see exits” type of talk, as if the bullet performance close up was not ideal, but the proof is in the pudding when they killed everything they shot with them in Africa.

 

[Randy11]

Is CX-BT a CX that someone physically removed the tip from?

@WCB

 

[Ringbill27]

Is CX-BT a CX that someone physically removed the tip from?

I was wondering the same thing. I remove the tips of that is the case.

 

[Randy11]

I was wondering the same thing. I remove the tips of that is the case.

I found the original post, and it is in fact someone physically removing the tip. Seems like a massive design failure.

Hornady’s New CX Bullet: How to Restore Terminal Performance

Hornady has released a new copper bullet called the CX to replace the GMX. The new 6.8mm version is also 100 grains like the GMX it replaces. Unfortunately, the new 6.8mm 100gr CX has demonstrated degraded terminal performance at impact velocities below 2300 fps causing the CX to act like an...

www.68forums.com

 

[SDHNTR]

Here is a decent example below.
ELDX or whatever bullet doesn't matter...at 100yds (high impact velocity) you will retain less weight (non mono) and the bullet will "curl back" further. As the bullet slows down/distance increases your weight retention will go up but the bullet will "curl back"/expand less. Your penetration will normally increase as distance increases as the bullet expands slower, less and maintains weight.

Will will not see the same wound channels at 100yds as you do at 400yds. View attachment 876886

What am I looking at in this picture here? Why does one show good expansion the other doesn’t? Are there two CX bullet types?

 

[Macintosh]

The cx pictured above is a mono, which has a different mode of functioning than a fragmenting bullet like an eldx does. I think that image is somewhat misleading as a result.
The expansion like you would see in a mono or a controlled expansion lead bullet like an accubond, etc works like that. But fragmenting bullets have an additional wounding mechanism on top of that, which the photo and description doesnt capture, where the bullet fragments themselves amplify the wound by cutting tissue while it is stretched, essentially making part of what would have only been the temporary stretch cavity into permanent wound channel.

Beyond that I cant help much.

 

[WCB]

What am I looking at in this picture here? Why does one show good expansion the other doesn’t? Are there two CX bullet types?

Looks like on removed the tip.... I found it on the inter webs. But the bottom row of bullets shows progressively less expansion as speeds slow down.

 

[SDHNTR]

Weird. I’ve shot them down to 2200 FPS with acceptable expansion.

 

[Fabel.52]

I was thinking starting a post on asking almost the same question. Using something like a 6.5 147 eld-m (creed vs PRC/ 26" barrel vs 16" barrel) or even a 178 eld-x from a 308 or 300 win mag speed at maybe closer more typical for me ranges like a 75-300 yards does the extra few hundred fps velocity kill game any faster? I understand the added benefit by increasing the distance to reach minimum expansion velocity. I am just not clear if the added velocity is likely to incapacitate animals faster at closer ranges. And if so is the added velocity likely unnecessary and could lead to more meat damage? Quick incapacitation and minimal animal suffering is high on my list of priorities.

 

[hereinaz]

I was thinking starting a post on asking almost the same question. Using something like a 6.5 147 eld-m (creed vs PRC/ 26" barrel vs 16" barrel) or even a 178 eld-x from a 308 or 300 win mag speed at maybe closer more typical for me ranges like a 75-300 yards does the extra few hundred fps velocity kill game any faster? I understand the added benefit by increasing the distance to reach minimum expansion velocity. I am just not clear if the added velocity is likely to incapacitate animals faster at closer ranges. And if so is the added velocity likely unnecessary and could lead to more meat damage? Quick incapacitation and minimal animal suffering is high on my list of priorities.

The overall difference is largely the shape of the wounding. The amount of wounding from an ELD x at 1900 fps is still more than most monos at high velocity, comparing same bullet size. Go look at the wounds in the .223 for bear, elk, moose... thread. You can't tell much about bullet size by the wound, but you certainly know it was a fragmenting bullet.

I've shot things at 100 yards at 3000 fps and lung flew out the exit. I've shot things and seen things shot out to 1000 with the same Berger bullet at 1900 fps.

They all died relatively quickly for body size, and using the double lung behind the shoulder shot, none went further than 70 yards. Most stood there a moment, tried to walk it off and then tipped over. Many I was able to put a second or third shot in, because they were not running. They didn't die any faster than animals hit with one bullet.

The time to death is so variable in my experience with 30 or so kills that you really couldn't tell which impact velocity killed faster. When hit in the lungs with the amount of devastation, a quick death is inevitable and the time to death is dependent on that animal size and will to live.

The only faster way to kill is a central nervous system hit.

 

[Jbehredt]

Think of it as a bell curve. There’s an optimum range and an acceptable range.

 

[Formidilosus]

Will the bullet "work" better at 400 yards compared to 600 yards since the impact velocity is higher at 400? Or is performance expected to be the same at both 400 and 600 yards since both are above the minimum fps needed . @Formidilosus

The higher the impact velocity, the more violent the upset- the wider the wound, and generally less penetration you get. So yes- higher impact velocity, more damage all else being equal.

 

[Kjc103]

The higher the impact velocity, the more violent the upset- the wider the wound, and generally less penetration you get. So yes- higher impact velocity, more damage all else being equal.

Could you bring some clarity then regarding using lighter than traditional calibers? I think I have you say that you have or routinely shoot elk at 700 yards with a .223/77 TMK. At that distance, it would be a sub 1,800 fps impact.

This seems to be pushing the limits of your 1,800-1,850 fps minimum recommendation for match bullets.

Ryan Avery is reporting great results with light calibers but he’s using a 6 UM pushing a DTAC at 3,300 fps.

I have an elk hunt in Idaho this year and I plan on bringing an 18 inch 6.5 Creed shooting the 130 TMK. I want to make sure I fully understand the limitations regarding impact velocity for a clean kill.

 

[Jordan Smith]

Could you bring some clarity then regarding using lighter than traditional calibers? I think I have you say that you have or routinely shoot elk at 700 yards with a .223/77 TMK. At that distance, it would be a sub 1,800 fps impact.

This seems to be pushing the limits of your 1,800-1,850 fps minimum recommendation for match bullets.

Ryan Avery is reporting great results with light calibers but he’s using a 6 UM pushing a DTAC at 3,300 fps.

I have an elk hunt in Idaho this year and I plan on bringing an 18 inch 6.5 Creed shooting the 130 TMK. I want to make sure I fully understand the limitations regarding impact velocity for a clean kill.

Each model of bullet behaves a bit differently when it come to minimum impact speed to initiate expansion. If you want to build some confidence in the bullet you're interested in, shoot it at distance into dry newspaper and see where it stop expanding properly. Newspaper isn't a perfect replication of tissue and bone, but it will give you some indication of what to expect.

While Form is certainly correct that with higher impact speed comes more violent expansion, as long as the bullet expands to ~1.5x caliber, it'll still kill effectively. Test it at the max distance you expect to shoot and see how it works.