Elk rifle question

[rileybassman]

Can you please educate me on how these calculations are made? I shoot several different rifles and loads; obviously it's dependent on muzzle velocity, but could use help understanding how the range/energy figures are calculated. Thanks in advance.

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Sure really not too difficult - it's based off of your bullet weight, diameter, ballistic coefficient, and velocity. There are many calculators online that can give you those figures... Heck even most ammo boxes will give you the figures at various yardages. You can either contact bullet manufactures or sometimes the bullet will state it's minimum optimal velocity for reliable expansion.

So for me, here is my 30-06 load:

180 grain accubond .308 diameter
2875 FPS (verified over Chrono and with 600 yard drop data)
BC = .507

Plug all that into my calculator and at my elevation with the cold weather I have now,
At 675 yards the bullet will be going 1808 FPS and have 1306 ft lbs... So that's my practical limit to follow the bullet optimal requirements.

A buddy's .308 data:
165 SST .308 diameter
2700 fps
BC .447

This buys him 500 yards exactly to get 1819 FPS and 1213 ft lbs... Assuming same bullet expansion velocities.

Hope this helps


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[ramont]

While the manufacturer's velocity and energy claims are a reasonable way to estimate the performance of a cartridge they are in no way accurate unless you happen to have the same barrel length and conditions as they had when they created their data.

The least expensive and easiest way to produce fairly accurate velocity and energy estimates is to chronograph your ammunition from your rifle. And even then you are creating a baseline that will change with altitude and weather. Using a reliable ballistics calculator you can then estimate the velocities and energies for your ammunition over the ranges that you intend to shoot game at.

As for the bullet's performance, contact the manufacturer (of the bullet and not the cartridge) and ask them what the minimum velocity is for their bullet to perform as expected (ensure that you are using a bullet that was designed for the kind of game you intend to hunt). Using that minimum velocity and your ballistics information you can find the maximum range that the bullet SHOULD work the way you expect...providing you can hit your target at the ranges that you want to hunt at.

P.S. I'm not trying to disagree with anyone I'm just trying to help explain in a little more detail how to best estimate a bullet's potential performance.

 

[YBPS]

Get a big 7 or a 30. 180 -200 gr bullet a few ribs back. Bang. Flop.

 

[elkduds]

Get a big 7 or a 30. 180 -200 gr bullet a few ribs back. Bang. Flop.

Not on elk, IME. Shot broadside through both lungs, an elk is probably going to travel 100ish yards before falling. A CNS hit is a different story.

 

[rileybassman]

Not on elk, IME. Shot broadside through both lungs, an elk is probably going to travel 100ish yards before falling. A CNS hit is a different story.

Every animal reacts different in different scenarios. I think a large part of the equation is how amped up/how much adrenaline the animal has in it's system before being hit. Last year both my sister and I shot 2 late season cows - after general season was over - and both cases they elk didn't know we were there, and both cases were bang flops. Shot with 140 grain 7-08 and 168 grain 30-06. Both broadside shots. I have also shot elk during rifle season when they are running from here to there... And almost always it's the 50-100 yard death run. Same type of experience with deer/antelope.

I think any animal that was spooked or running or has adrenaline will always go down harder... Baring CNS shots of course.


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[YBPS]

Get a big 7 or a 30. 180 -200 gr bullet a few ribs back. Bang. Flop.

Shoot Bergers. They don't go anywhere.....