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energy requirements

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Unread 02-14-2006, 07:14 PM
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Join Date: Sep 2004
Location: on the rifle range in Utah
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Re: energy requirements

I have deduced from several elk taken past or around the half mile mark that it seems 800 ft-lbs is needed to break the shoulder blade/spine area of a full grown elk. This has been similiar to findings done by other well known bullet experimenters.

That being said, you need to have more than just kinetic energy to kill elk. Bullet construction is crucial like others have already mentioned.

Shot placement is debatable as is bullets to be used. My line of thought (that I have been convinced of through actual field experimentation) suggests that the only way to anchor a big animal from long range with any degree of reliability is to either hit it in the shoulder, spine, or head. Heart shots just don't seem to drop them immediately at long range although they will kill indefinetly.

Bullet construction for long range hunting puts different demands on a bullet than short range hunting. A more frangible bullet is desired for hits below 2500 feet per second, and a stouter bullet for magnums at close range is required. This is where bonded boat tail bullets shine. They have the best of both worlds. Long and short range can be tackled without swapping bullets. Very nice. [img]/ubbthreads/images/graemlins/wink.gif[/img]
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Unread 02-17-2006, 02:57 AM
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Re: energy requirements

Energy is a subjective term and subject. 5000 FPE wont do you a bit of good if you are using full metal jacket bullets. The game will run a LONG way with a minimal blood trail before expiring.

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I think you mean the energy required to kill an animal is subjective. Energy is completely deterministic and predictable - a simple 1/2 M*V^2 and you should know the V (from your range finder/ballistics table).
I disagree with the ancient African rule calling for low velocity bricks in lieu of modern high velocity bonded projectiles.

You would have a very hard time finding any bullet with 5K FP (and a reasonable shot) that would not quickly dispatch an elk. It would either have to be a HUGE bullet (large wound channel) or a small bullet with ultra high velocity (again producing a large would channel. But your point is well taken, API is not for hunting generally speaking. (I know a few guys who've shot deer with 50 BMGs using API - no problem with wound channel despite ZERO expansion.)

The energy dissipated into the animal (or any other body) can easily be computed via conservation of momentum and energy.


... Bullets such as the ACCUBOND open at lower velocities and stay together on the close up shots.

[/ QUOTE ]

Amen, compare GGs long range elk kill and Shawn's close range deer splatter (I think he was using his 338 & a MK - at close range the MK splattered). You make good points, I just wanted to clarify the energy info.
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Unread 02-17-2006, 06:29 AM
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Join Date: Feb 2005
Location: Texas born and raised
Posts: 752
Re: energy requirements

Well this may or may not help you, but it is what I went through several years ago preparing for two different hunts.

First was a trip up to WI. for whitetail using a Contender in 7x30 Waters. Knowns, low velicity impacts, realitive weights of area game around 300#, ranges from 25 - 300yds. With this in hand I got on the only ballistic program I had at the time and started running numbers. I needed the highest retained energy for range of the bullets I had to choose from first. Then once I had this I called the manufacturers of these bullets for the lowest impact velocity which would give full or at least double caliber expansion. For the 140gr weights, this was in the 1600fps range. So now I started load development. I had three bullets which would or were supposed to perform in my range of loads. My finial load was using the 140gr Nosler BT moly coated, which I loaded to 2350fps. The groups were under 1" from a solid rest at 100yds, and all testing done showed great expansion on real targets out to 300yds. Didn't get a deer in WI., could have, my choice, but took a nice fat doe back here at 285yds. At the shot, just behind the left shoulder quartering away, it dumped her on her head and all was done.

Same situation, for 7mm Rem Mag. headed to CO for mule deer and elk. Had no clue as to terrain we would be hunting, never been there before. The area has everything from flat open plain to look up or down 90 degrees. So repeated the process. At the time, there were no AB type bullets out, so I went with the heavies once again. Needed the most velocity, best groups, and highest retained energy at my implimented max range of 600yds. After working through several loads I went with the Hornady 162gr SPBT again moly coated. For the particular load and temps in which it was developed as well as expected temps, the groups were around 1.5" at 300yds. The velocity was 3150fps. out of this particular rifle. Yes it is a smoker but the only time pressure becomes an issue is in temps above 75 degrees. Not a problem for when and where we hunted. Didn't get a chance to try it out on the hunt in CO but have taken several hogs, and this nice buck at 285 yds, no problems.

The Hornady 162gr has done us proud on several long shots out to 400yds on big hogs. Several over 300# have been taken from various angles and all dropped to the shot.

Penetration on this one taken from 350yds, was from right rear ham, blasted through the pelvis, up through and broke the left shoulder and came to rest under the hide just under the jawbone. That is around 3+ feet of tough stuff. I am sure that if you get the 160gr AB's moving at top velocity in your rifle that you will have what your looking for. I would have more than likly went with them had they been out at the time. I tried the PT's, and the XBT's, but couldn't get the accuracy I was looking for.

Good Luck, and remember that in the end, accuracy, and sectional density, will do a lot more for you at the longer ranges and lower velocities than sheer energy numbers. Those long bullets have a knack for plowing through and doing a number on stuff in their way. Just look at the old long 6.5x55, 7x57 and .303 British bullets, that have taken so much game from around the world. It dang sure wasn't from sheer horsepower.
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