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Optimum and Maximum Practical Game Weight

9911 Views 39 Replies 12 Participants Last post by  mikmarandola
I have searched the internet for Information on stopping power and formulas and tried to figure a formula to account for explosive wounding. This formula can be found under Hunting Stories, perhaps the wrong place to put it..

As I said before I think the Taylor, Hatcher and Thornily formulas to be among the best. I found a post on a forum claiming the Optimal game weight formula to be the best. I found a ballistic program which whilst calculating a ballistic chart also would calculate Taylor's knockdown number or any other of twenty-six knockdown formulas.

The text attached to the program gave the formulas, plus other formulas to calculate gel wood and steel penetration. It also had a chart for each formula so you could know what was needed for each class of game. When you calculated the number for a deer rifle on Taylor's chart, then calculated the number for almost any other formula it still came out as a deer rifle. So it matters not what formula you use as long as you have a chart to go with it.

I then thought what is the best formula. Going back to what I know.

1/ The 45 auto has a great reputation for short range stopping power. It loses 30ft/sec over 100yds so it doesn't lose much stopping power over distance.

2/ The 30 cal carbine was considered to be a bit marginal when it came to stopping determined enemies.

3/ The 223 Armalite/M16 could inflict terrible wounds (at short range) due to explosive wounding and or an unstable bullet.

I think these guns should be rated 1, 3, 2, or perhaps 3, 1, 2, at very short range. Looking at these weapons using OGW gives 1/ = 41lb 2/ =141lb 3/ = 97lbs.
The advantage of this formula is obvious, a 150lb deer is to much for a 45 auto, or is it.

There were several game weight formulas with my ballistics program. My favourite Maximum Practical Game Weight uses Energy calibre and bullet weight to produce the target game weight. EN x BW x CAL divided by 100
1/ = 341lb 2/ = 203lb 3/ = 111lb if these weights are the maximum you can expect to get a quick kill with a well placed bullet. I then divide by 2 to get what I consider the "Optimum" game weight". The result means (3/ = 56) the Armalite/M16 could be relied on to take down coyotes at over 100yds. If the game is dangerous divide by 4, e.g. You have just been surprised by a 120lb mountain lion at 50 paces you can't rely on a 45 auto (1/ = 85) to stop it with one shot.
I haven't forgotten about bullet types I would multiply the above numbers by Hatcher's bullet chart e.g. 0.9 for FMJ, 1 for LRN. I have read that pointed bullet tend to tumble for these I would use a factor of 1.5 which still doesn't turn the Armalite/M16 into a good deer rifle.
With these and most other stopping power formulas a base ball has more stopping power than a big game rifle. However apples are not oranges and a baseball is not a bullet. The formula I Have for Gel Penetration is:
MOM divided by Cal^2 x 6.625
This gives a gel penetration of .9 inches hardly what is required for an offensive weapon.
As for explosive wounding as far as I know it seems to happen with very high velocity bullets. Perhaps this is already figured in the formula as energy increases with the square of velocity so does the expectation of explosive wounding occur.
After much study these two formulas seem much better than I originally thought.
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Jason, you might to consider that deer aren't the same size all over the country. You guys up north would laugh at what we consider a full-grown deer over much of the south. In the Texas hill country, a hundred pounds dripping wet is a darn good deer.

Up in say Montana, that same sized animal wouldn't survive the winter.

Deer hunting is not the same sport all over the country. While I prefer a .25 cal minimum for a hunting rifle for myself, it's for the pigs, not the deer. I have seen a few small hogs killed with a .223 and the right bullet, also.
I don't agree that you can predict how far a lung-shot deer will run, with anything.

What might be claimed is that the bigger calibers leave a better blood trail, and that is fine with me. Depending on where you hunt that could be a serious issue, or no consequence whatsoever.
Furthest iv seen a good double lunged buck go is about 70 yards. that was with a 30-30 with 170 grain corelokts at 5 yards, on a fairly calm deer. If one never had to worry about having a blood trail, i guess a .223 rem with proper bullets could probably be "suitable" for most anything in the lower 48. Most places that i have seen, where deer hang out also have at least some cover... just saying.
Well I have trailed lung-shot deer farther than that, at least double on a couple of occasions. Not that I'd prefer to, that's just how it works out sometimes. You never know. Two instances that come to mind were with my .257 Weatherby and .30-06, so it can happen with the bigger stuff too.

We also generally hunt from fixed blinds, which makes a world of difference in having a steady rest. Also, quite a few of the deer that get shot with .22 and .243 cal rifles are does and such being harvested for the freezer. It makes a big difference when you have high density and a season 2-3 months long; you can pass up those marginal shots and go out another day.
To Barkbuster: I don't think it is legal to use dogs for trailing up deer in Texas anymore. Not sure but I don't have one suitable, anyway.

To Jason: One very long tracking job had the bullet stop on the opposite side, barely poking out. The only blood was likely from the entrance hole. The other was a through and through shot. So, both can happen. I'll take an exit hole and blood any day though.

To the original poster: I think this illustrates why the formulas are all pretty well useless in the real world. There is just such a variety of experience under what might be near-identical conditions. One animal drops dead, another goes many hundred yards, etc., etc. No formula can explain such a thing.
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