Primary Organs - Vital Zone (Gearbox) Sizes

[M Rosslee]

Good day all,

For comparative interest.

What are your general accepted dimensions for the vital zones and shoulder heights (side-on view) of medium game (whitetail, mule deer, pronghorn, bighorn etc.) and large game (elk, moose, caribou etc.) ?

I suppose on African plains game we're looking at the following:

around 15cm x 15cm (around 6"x6") vital zones and 1m shoulder height on smaller antelope like springbuck

around 20cm x 20cm (around 8"x8") vital zones on medium game (blesbuck, impala, bushbuck, blackwildebeest) and a shoulder height of around 1.2-1.3m

around 10" x 10" on large game (zebra, bluewildebeest, kudu, redhartebeest, gemsbuck etc.) and around a 1.5m shoulder height

Are my estimated vital zone sizes close to yours?

It's an interesting comparison and I'm giving a lot of thought to pursuing long distance hunting here, with due regard to ethics which is directly linked to me being able to shoot groupings sub vital zone size and on target...

Look forward to your responses.

 

[J E Custom]

Good day all,

For comparative interest.

What are your general accepted dimensions for the vital zones and shoulder heights (side-on view) of medium game (whitetail, mule deer, pronghorn, bighorn etc.) and large game (elk, moose, caribou etc.) ?

I suppose on African plains game we're looking at the following:

around 15cm x 15cm (around 6"x6") vital zones and 1m shoulder height on smaller antelope like springbuck

around 20cm x 20cm (around 8"x8") vital zones on medium game (blesbuck, impala, bushbuck, blackwildebeest) and a shoulder height of around 1.2-1.3m

around 10" x 10" on large game (zebra, bluewildebeest, kudu, redhartebeest, gemsbuck etc.) and around a 1.5m shoulder height

Are my estimated vital zone sizes close to yours?

It's an interesting comparison and I'm giving a lot of thought to pursuing long distance hunting here, with due regard to ethics which is directly linked to me being able to shoot groupings sub vital zone size and on target...

Look forward to your responses.

My personal Opinion is that I must Hit within a 3" circle Of the point of aim on anything. (Preferably
1 MOA.) and limit my distance so I can accomplish this.

The larger animals can increase the distance because of the chest size, but I still want to hit inside a
3" on deer size and 5" on Elk and larger.

I realize that there is more room for error on some very large game, But if I don't think I can stay
within my limits I pass on the shot. With all of the advancements in ballistics and Powders, this degree of accuracy is very possible.

At close distance (400 Yards or less) these limits are easy to accomplish. Beyond that, it gets harder.

It is very important to know how large the vital zone is and your estimates are very close so you should have a good chance of success.

Good hunting

J E CUSTOM

 

[Frank in the Laurels]

Let's make it easy...heart lungs...can you hit a basketball...your good enough !

 

[M Rosslee]

Sure thing.

I've had a successful vital hit on a wounded gemsbuck at 420m, quartering away and the 250gr .338 bullet smashed into the opposite shoulder (entered behind the back rib and through the rumen) -note - the shoulder bone stopped the bullet at 420m. That is a 250gr projectile moving at 2700fps.

I measured the lungs in their inflated and deflated state - the difference was about 4" on a 10" x 10" pleural cavity...

So your shots should be within a 6"x6" circle around your aimpoint at whatever range you're shooting at. Interesting... and that is on BIG VITALS.

Springbuck vitals are a half (maybe even less) of that in radius... So I guess your rifle needs to be shooting 1/3 MOA at 1000m if you want to shoot springbuck and 1/2MOA if you want to shoot larger game...

Starting to make sense...

I'm considering a 30" 1:12" twist barrel on my .308 Win Remington VLS, which currently dons a 26" 1:12" twist... I can throw a 155.5gr Fullbore VLD at around 3000fps to keep it supersonic at 1000m... Will just maintain penetration qualities better and avoid transonic flight characteristics...

Very interesting... Energy is greatly reduced so at 1000m your shot needs to be a heart shot on the more serious thick-skinned game and away from shoulder bones... That means your horizontal deviation needs to be nearly zero.... You can't (on a left facing animal) stray left into the shoulder bone and right into the rumen...

You effectively have 2/3 of the vital radius to hit (1/3 reduction due to thick shoulder muscles and bones) which is around 7"x7" on large game ...

Small game doesn't really matter - the small bones and thin skin don't offer substantial resistance to a ballistic projectile travelling at supersonic velocities...

 

[FEENIX]

Aim small, miss small ... this is one of my all time favorite videos ...

[ame]https://youtu.be/cTDypg4OAFA?t=55[/ame]

The guys in the video are LRH members, shooter is Joe (TGRMAN) an excellent LR gun builder and Jeff (BROZ), well you all know him , was spotting for Joe.

Let's make it easy...heart lungs...can you hit a basketball...your good enough !

Aye Sir!

(Off a muley buck, 311 yards with 175 Matrix VLD out of .270 AI)

 

[M Rosslee]

Just to give a clear indication ... Compare the mature impala ram to the kudu bull in size and consider respective vital sizes.

 

[M Rosslee]

Aim small, miss small ... this is one of my all time favorite videos ...

https://youtu.be/cTDypg4OAFA?t=55

The guys in the video are LRH members, shooter is Joe (TGRMAN) an excellent LR gun builder and Jeff (BROZ), well you all know him , was spotting for Joe.

Fantastic to watch!

 

[M Rosslee]

Aim small, miss small ...

Couldn't agree more

If it's within 150m I shoot for the grey matter...

 

[M Rosslee]

In some regions in SA, we have to make long shots on smaller species such as springbuck and blesbuck... These were both taken at distances exceeding 300m (the stalk was impossible and the herd sees you from a mile away)... Consider the size of the vitals... 30-06 and 338 Winchester Magnum