The Hourglass Effect

[ChrisWay]

When choosing ammunition for long-range precision shooting, wind resistance is a critical factor. In this article, I explore what I’ve termed the “hourglass effect”; which examines the performance differences between lighter rounds and heavier rounds of the same caliber. Future articles will delve into other important elements of the larger topic of weight speed and distance. 









Im calling it the hourglass effect because before the convergence, one round has an advantage and after the convergence, the other takes the lead with respect to wind. Thinking about a field of fire as a shape can help dissect zones where you might choose one round over another. This bullet comparison can be done for any rounds, but it shows a distinct patterns. Due to the large weight and velocity difference between the bullets used we can see that bullet choice is an important decision point for a rifleman. Plus i’m visual and like to describe things with visual elements....

Continue reading...

 

[Lowlight]

Light is Right ....

 

[Lowlight]

 

[stanley_white]

Is there a “light is right” for 308 @Lowlight?

-Stan

 

[Lowlight]

The 155 is where most went, but you need a pretty good barrel to get the speeds right, we need like a match 145 or 135

 

[Basher]

The 155 is where most went, but you need a pretty good barrel to get the speeds right, we need like a match 145 or 135

I went with the 168 ELD-M as a result of the “short barrel” podcast you did a few years back. My .308 is an FN SPR 20”, so I wanted to be able to push them as fast as I could out of that barrel to maximize its potential. Do you now feel the 155gr ELD-M is a better option? I’m not opposed to switching, that chrome-lined bore should last me another 8K rounds or so…

Edit: read the article (which I should have done first), and was surprised by the results but only slightly. I expected there to be less drift and drop from a lighter projectile (with gravity being a constant, reaching the target faster means less time for the bullet to be acted upon). I did not, however, expect that to be true out to 900 yards! Looks like I need to get a few boxes of 155s to test out!

 

[Franko]

Excellent food for thought.

Thank you.

 

[hero's machine]

I tried the 250s in my 338edge after some comments Frank made.

I am beyond impressed with them to the mile mark.

 

[BuildingConceptsllc]

Very interesting stuff. Thank you. I love reading stuff like this

 

[Lowlight]

Here are some of the charts

 

[Sisan_03]

Excellent post

 

[Takashi]

What is the Y-Axis on this last chart?

 

[ChrisWay]

What is the Y-Axis on this last chart?

wind hold

 

[aprocast]

Can you provide a scale for the charts please