Brush Bustin'

[toebako]

It all boils down to physics, specifically, momentum. If a semi and a Mini Cooper are both going down the highway at 100 km/hr and both hit the same snowdrift at the same angle, the Mini Cooper is going to get deviated a lot more than the Semi, simply because the Semi has a lot more momentum.

The formula for momentum is mass times velocity. A simple way to compare the brush busting capabilities of various cartridges is to multiply the weight of the bullet by its velocity and divide by 7000. Where did the 7000 come from you ask? Well, there are 7000 grains in one pound. So for a 500 grain bullet fired from an old Springfield Trapdoor at 1,300 fps, the momentum is 93. Now take your favorite cartridge, do the calculation, and compare.

If you can put some spin on the mini and the semi then you can compare. As the amount of spin on the bullet will help stabilize it also.

I heard the dowels and box thing made a 25-06 look real good, and the 45/70 not so good on one test but can't remember where it was now. The y said it was the spin that helped. The 22-250 also did good. Need lots of dowel and guns to prove this out. Good luck.

 

[DIESEL WEASEL]

I would be interested to know how the results of Tod's test would change if say he shot through a small bush/branch near the muzzle and put the target out at 100m.

I took a 185yd(ranged) shot at a moose once from a solid bipod rest. Through the scope it looked like a small christmas tree size sapling was covering a good part of his vitals. With the scope on 9X it looked as if the tree was fairly close to the moose like 20yds or so. I chambered a 180gr swift scirocco handload in my 300 WSM (3000fps) and squeezed one off with the vertical crosshair just slightly behind the shoulder hump and the horizontal crosshairs about a foot and a half below the hump. The actual crosshairs were pointing at the tree branches about a foot from the branch tips(nowhere close to the trunk).

Anyhow I heard the shot hit like a drum. The moose was standing on the fringe of a new cutblock facing into forest. When the shot hit he took off into the bush. I radioed my buddies that were at the far end of the block behind me to come over my way and help me retrieve the moose.

Premature Celebration!

I dropped a ribbon on the stump that my bipod was resting on and went to find the spot where the moose was standing. In less than 100yds I came upon the tree which I thought was just in front of the moose. 90 yds or so later I found the spot where the moose had jumped forward after impact. Me and two buddies spent the next three hours following tracks without any evidence of blood.

I know the shot was good out to the tree, however a 1/2 degree deflection for almost 100yds = 30 inch deflection. Unfortunately I didn't understand that at the time. I know for a fact that the bullet hit(even though I found no blood), just by the sound. A 180gr bonded bullet at 3000fps MV should have enough energy to easily dispatch a moose at near 200yds. And yes I have recovered a few Sirocco's to prove it.

I'd really like to see a test where tipped bullets vs. TSX vs. soft point. vs big bore flat meplat are shot with say a tuft of buck brush near the muzzle and target 75-100yds away. Not that I would every try that shot again, i've just always wondered where that bullet struck.

I do shoot prone off of bipods quite often in cutblocks and have found that tall grass doesn't seem to affect hits on 3MOA gongs/balloons but I've never tried it on heavier brush.

 

[mike shickele]

There is absolutely no evidence that any cartridge in existence can go through brush without being deflected. The brush cartridge is a myth that has been perpetuated for years. If you don't have a clear shot, wisdom dictates that you don't squeeze the trigger.............my thoughts.
Mike

 

[curtmg]

You huntin with Dill these days?

He said 2 shots, not 20

That's the problem with the old 7600, by 15-16th shot, the barrel starts to heat up, and it really affects your accuracy.

 

[Win 38-55]

The momentum I mentioned earlier is the main factor in minimizing deviation, but spin also helps in the stablization. Here again, the large caliber bullets have the advantage. The angular momentum of a spinning bullet is proportional to the square of the radius. Thus, for the same spin rate, a .458 diameter bullet will have about 4 times the stability of a .223 bullet. The smaller caliber can compensate for this by spinning 4 times as fast. Note we are not talking simply of the number of twists per inch in your barrel, but also how fast the bullet is going when it leaves the barrel, which translates into a spin rate (rounds per second). If a fellow knows the twist rate in his barrel, and the muzzle velocity, he can calculate the spin. However, when the dust has cleared, the large diameter, heavier bullet sets the bar high enough for both forward momentum and angular momentum, that is is very difficult for smaller caliber, lighter bullets to meet it. That is why it is easier to destabilize a 223 than a 500 grain .458 bullet. As mentioned above, all bullets will deflect ....... however, some will deflect a lot more than others. That is also why large diameter, heavy bullets are used for large dangerous African game than lighter, smaller bullets. The larger forward momentum and larger angular momentum permits the larger, heavier bullets to plow through more large bones and muscle without tumbling, resulting in deeper penetration.

 

[Johnn Peterson]

Any bullet coming into contact with a resistance in its path to a target will be deflected as mike shickeles stated. I also concur with his 'take' on shooting through brush at game. By posting to this thread and suggesting further possible tests I'm not trying to advocate or encourage doing so. For me, even though being a fan of Elmer Keith, the question is mainly one of curiosity at this point. As it has been said, this is a question that has been batted around and debated for many years and probably won't stop here either.

I guess the basic concept or question we started out with is which bullet would be would be affected the least by a resistance, the lighter faster smaller bullet or the large caliber slower moving and heavier projectile. I tend to agree with Win 38-55's 'physicis' example as quoted by toebako and if I had to bet without any testing, my vote would be for the big, heavy and slow being deflected less.

To attempt to answer that basic question and come up with a fair test, what I see as the biggest hurdle is coming up with a medium that will replicate the exact same resistance for every shot and by each caliber tested. A 'possibility' came to the forefront yesterday evening when I was reading about a LEO experience years ago on shooting at a fleeing vehicles rear windshield with a 38 spl. PLEXIGLAS!!

What I'm 'thinking' of is to place a small piece of plexiglas held on a stand, say 5' - 10' infront of a target and angled to one side at about 45 degrees and inserting a new piece for each shot. The are a few main benefits as I see it are;
1/ you see the target so your point of aim is always the same.
2/ Changing out the piece of plexiglas for each shot, the resistance is always the same.
3/ Could probably done with a minimal number of shots/caliber.

I like the idea of a dowel box type medium and although it may be somewhat closer to 'shooting through brush', how do you keep the resistance equal for every shot to come to a fair proper conclusion?

Again gentlemen, your input and comments? I'm thinking tentatively of three shots and with three calibers, small, medium and large.
A/ 219 Donaldson Wasp
B/ 30-06
C/ 458WM

While I 'think' that in all fairness I may have addressed one variable, another possible variable comes to mind. Bullet profile or shape.

 

[Win 38-55]

The dowel approach does have repeatability problems ..... you never know if each bullet is hitting a doweling at exactly the same way every time. Here's a post on bullet resistent glass . http://www.theboxotruth.com/docs/bot6.htm

The physics of this problem is very straight forward. As I mentioned above, the primary factor is forward momentum. A secondary factor is spin/angular momentum, favoring the larger diameter bullets. One other factor not mentioned yet is a flat meplat. The large flat meplat seems to penetrate further with less deflection than the pointy-nosed bullets.

I like the plexiglass experiment that is proposed above. Seems to me it should tell the story.

 

[Calum]

There is absolutely no evidence that any cartridge in existence can go through brush without being deflected. The brush cartridge is a myth that has been perpetuated for years. If you don't have a clear shot, wisdom dictates that you don't squeeze the trigger.............my thoughts.
Mike

X2!

 

[Gatehouse]

Before everyone starts contruscting intricate tersting devices, they shoudl do some searching on the intraweb. I know of half a dozen articles about tests performed with dowels, piled up brush, shooting with the target at different distances behind the brush/dowells etc.

General consensus was :


1.that the closer the target was to where the bullet hit the wood, the better
targets further back from the impact would have less chance of good hits
2.all bullets deflect somewhat when hitting brush
3.bullets that "center punch" a branch are far more likely to continue on course than bullets that impact on the edge of a branch
4.Big, slow and heavy bullets weren't any better at "bucking brush" than other bullets
5.Best brush buckers seem to be the longer, heavy for caliber bullets with high SD, like 175gr 7mm, 160gr 6.5, 200gr .308 etc
6.Shooting through brush is risky at the best of times.

[/LIST]

 

[Eagleye]

There is absolutely no evidence that any cartridge in existence can go through brush without being deflected. The brush cartridge is a myth that has been perpetuated for years. If you don't have a clear shot, wisdom dictates that you don't squeeze the trigger.............my thoughts.
Mike

Absolutely agree with this!! Eagleye.

 

[Johnn Peterson]

Before everyone starts contruscting intricate tersting devices, they shoudl do some searching on the intraweb. I know of half a dozen articles about tests performed with dowels, piled up brush, shooting with the target at different distances behind the brush/dowells etc.

General consensus was :


1.that the closer the target was to where the bullet hit the wood, the better
targets further back from the impact would have less chance of good hits

And that's understandable. The angle of deflection is what it is but the increased distance to target is proportional to the distance of deflection from point of aim.

2.all bullets deflect somewhat when hitting brush

No arguement and I've already agreed with that statement made by someone in a previous post.

3.bullets that "center punch" a branch are far more likely to continue on course than bullets that impact on the edge of a branch

Again, that's understandable.

4.Big, slow and heavy bullets weren't any better at "bucking brush" than other bullets
5.Best brush buckers seem to be the longer, heavy for caliber bullets with high SD, like 175gr 7mm, 160gr 6.5, 200gr .308 etc

That I don't know personally, but I'll take your word for it.

6.Shooting through brush is risky at the best of times.

As I mentioned before, it isn't something I'm advocating, but for me at this point, it was merely a aspect of curoisity.

[/LIST]

Thats exactly what I was attempting to stay away from and I thought what I was proposing as a test was not only uniform from shot to shot but also as simple as possible by virtue of that uniform test medium.

Okay though, if this question has already been delt with and the results or popular consensus of opinion have already been reached, not much sence in 're-inventing the wheel'.

Oh, by the way, concerning what the basic question was, of which is more affected by interferance, what were the findings? Fast & light or slow & heavy?

 

[Win 38-55]

As much as I think shooting through dowlings is a poor way to test bullet deflection in brush, here's an test done with shooting through dowlings http://www.theboxotruth.com/docs/bot40.htm His findings are as follows:

Lessons learned:
1. Light weight, fast bullets like the .223 were knocked off their axis and deflected more than heavier bullets. In fact, it was flying sideways after 10 yards.

2. The .308 was not deflected as much as I would have thought. Not enough to miss a deer 10 yards behind the brush.
3. The .45-70 plowed through the dowel without much deflection.

4. The 12 gauge slug shrugged off the dowels and went right on to the target.

For those who have been pointing out the obvious ... that all bullets will deflect in brush, that is not what the question is about. The question is which bullets will deflect more when they strike a twig/blade of grass/leg bone. Bullets have to obey the laws of physics just like any other moving object. As much as I don't recommend taking the shot if it is not clear, to say that bullets with more momentum will deflect just as much as those with less is nothing short of appealing to magic. It would require a violation of physics to make all bullets deflect the same amount given identical strikes on twigs/grass/leg bones. 'Brush busting' is a bad idea, but unless we are suspending the laws of physics, some bullets will 'bust brush' better than others (i.e., deflect less); that is not a myth. To illustrate this, stand at the top of a large hill with a good stand of brush at the bottom and roll a 300 pound boulder down the hill into the brush. Then fire a BB into the brush and see which one is deflected less by the grass/twigs. For Pete's sake, make sure the brush at the bottom of the hill doesn't have anyone in it. This exaggerates the difference in momentum, but the same physics still applies to bullets.

Here's another way of proving that bullets with more momentum will deflect less for the same twig. First, understand the Conservation of Momentum law (see http://en.wikipedia.org/wiki/Momentum ). That will enable you to precisely calculate the deflections. Now set up two experiments. Take two steel tables, both of them with a single BB sitting on it. For table one, fire a BB at the stationary BB such that the fired BB contacts about 1/2 way out from the center of the stationary BB. Assuming both BB's weigh the same, and you know the muzzle velocity of the fired BB, you will observe both BB's depart from each other at approximately a 45 degree angle from the line of firing, and they will both be moving at approximately half the muzzle velocity of the fired BB. The momentum of both will sum to the original momentum of the fired BB just before it contacted the stationary BB. (This is kind of like playing pool with different weight balls .... in fact, those who say that all bullets defect the same amount should have no problem playing pool with balls that differ widely in their weights.)

Now go to the second table and fire a 500 grain .458 bullet at 1,400 fps at the stationary BB, hitting it at the same spot as you did the other BB. You will observe the 500 grain bullet deflect at a very minute angle, while the BB deflects at almost 90 degrees to the line of firing. The momentum of both will sum to the original momentum of the fired bullet before it contacted the BB.

I hope that I've made it clear why bullets with a higher momentum will deflect less than bullets with a lower momentum when striking an object the exact same way. Gatehouse's point (4) is only true for 'slow' big heavy bullets. Again, there is no magic here ..... a 500 grain bullet traveling at 1,400 fps will deflect exactly the same amount as a 250 grain bullet traveling at 2,800 fps since both have identical momentum (though not likely the same angular momentum). In other words, big, heavy, fast bullets will deflect less than big, heavy, slow bullets as dictated by the conservation of momentum law.

For those of us who abstain from shooting through brush, this whole discussion is still relevant when it comes to bullet/cartridge choice for hunting. It is for the same principles discussed above that I don't use a 22 rimfire when hunting black bears, or a 30-30 for hunting Cape Buffalo (not that I'm ever likely going to get a chance to hunt Cape Buffs). A bullet with more momentum is less likely to be deflected by a leg bone or other heavy bones.

I wrote an article on this in Hunting and Shooting in the March/April, 1996 for those who are interested in yet another article about this.

 

[Johnn Peterson]

As much as I think shooting through dowlings is a poor way to test bullet deflection in brush, here's an test done with shooting through dowlings http://www.theboxotruth.com/docs/bot40.htm His findings are as follows:



For those who have been pointing out the obvious ... that all bullets will deflect in brush, that is not what the question is about. The question is which bullets will deflect more when they strike a twig/blade of grass/leg bone. Bullets have to obey the laws of physics just like any other moving object. As much as I don't recommend taking the shot if it is not clear, to say that bullets with more momentum will deflect just as much as those with less is nothing short of appealing to magic. It would require a violation of physics to make all bullets deflect the same amount given identical strikes on twigs/grass/leg bones. 'Brush busting' is a bad idea, but unless we are suspending the laws of physics, some bullets will 'bust brush' better than others (i.e., deflect less); that is not a myth. To illustrate this, stand at the top of a large hill with a good stand of brush at the bottom and roll a 300 pound boulder down the hill into the brush. Then fire a BB into the brush and see which one is deflected less by the grass/twigs. For Pete's sake, make sure the brush at the bottom of the hill doesn't have anyone in it. This exaggerates the difference in momentum, but the same physics still applies to bullets.

Here's another way of proving that bullets with more momentum will deflect less for the same twig. First, understand the Conservation of Momentum law (see http://en.wikipedia.org/wiki/Momentum ). That will enable you to precisely calculate the deflections. Now set up two experiments. Take two steel tables, both of them with a single BB sitting on it. For table one, fire a BB at the stationary BB such that the fired BB contacts about 1/2 way out from the center of the stationary BB. Assuming both BB's weigh the same, and you know the muzzle velocity of the fired BB, you will observe both BB's depart from each other at approximately a 45 degree angle from the line of firing, and they will both be moving at approximately half the muzzle velocity of the fired BB. The momentum of both will sum to the original momentum of the fired BB just before it contacted the stationary BB. (This is kind of like playing pool with different weight balls .... in fact, those who say that all bullets defect the same amount should have no problem playing pool with balls that differ widely in their weights.)

Now go to the second table and fire a 500 grain .458 bullet at 1,400 fps at the stationary BB, hitting it at the same spot as you did the other BB. You will observe the 500 grain bullet deflect at a very minute angle, while the BB deflects at almost 90 degrees to the line of firing. The momentum of both will sum to the original momentum of the fired bullet before it contacted the BB.

I hope that I've made it clear why bullets with a higher momentum will deflect less than bullets with a lower momentum when striking an object the exact same way. Gatehouse's point (4) is only true for 'slow' big heavy bullets. Again, there is no magic here ..... a 500 grain bullet traveling at 1,400 fps will deflect exactly the same amount as a 250 grain bullet traveling at 2,800 fps since both have identical momentum (though not likely the same angular momentum). In other words, big, heavy, fast bullets will deflect less than big, heavy, slow bullets as dictated by the conservation of momentum law.

For those of us who abstain from shooting through brush, this whole discussion is still relevant when it comes to bullet/cartridge choice for hunting. It is for the same principles discussed above that I don't use a 22 rimfire when hunting black bears, or a 30-30 for hunting Cape Buffalo (not that I'm ever likely going to get a chance to hunt Cape Buffs). A bullet with more momentum is less likely to be deflected by a leg bone or other heavy bones.

I wrote an article on this in Hunting and Shooting in the March/April, 1996 for those who are interested in yet another article about this.

Excellent guy, thanks. I guess perhaps I didn't sleep through all my high school physics classes after all. Good info and great back up picture set-up. Thanks again.

 

[Gatehouse]

Oh, by the way, concerning what the basic question was, of which is more affected by interferance, what were the findings? Fast & light or slow & heavy?

Most of the articles that I recall said that neither one had a real, measurable edge, everything deflected somewhat and the real deciding factor had more to do with how close the target was behind the obstruction, and how the bullet hit the obstruction.

I'm sure we could find ways to factor in bullet construction and everything else somehow...But I'd probably just avoid taking shots where the screen is dense.

 

[Win 38-55]

...But I'd probably just avoid taking shots where the screen is dense.

A good policy. Personally, I'd avoid going hunting with someone who practiced 'brush busting'.

 

[Johnn Peterson]

A good policy. Personally, I'd avoid going hunting with someone who practiced 'brush busting'.

And I second that motion. Again, for me it is mainly a point of curoisity but I have a friend that guides in the central B.C. interior that may find the results discussed interesting. He has recounted a couple of experiences where the topic and findings of so called 'bush busting' may be of interest to him. There have apparently been a few occasions where he's had to go in and 'locate' a Grizzly wounded by a client and a couple of similar cases on Moose. The moments are or can be tense, the range close, thick terrain and the action quick.

My 'main' point of interest, once again, was the angle of deflection with the distance to target remaining a constant. I think we all realise the greater the distance between the obstruction struck and the target, the greater the error or miss from point of aim will be. That's a givenSo, which of the two basic differences or examples of bullet weight and speed would show the least effect to impact with an obstacle on its path to target? Keeping the medium equal and uniform for each shot I thought would show a truer picture and in all likelihood varify the physics involved.

 

[Levi Garrett]

A good policy. Personally, I'd avoid going hunting with someone who practiced 'brush busting'.

Ya , I let 'em walk...right into an opening

 

[.Ben]

I wouldn't knowingly shoot through any brush with any cartridge.

I recently read an article of a fellow who landed a bad shot on a Cape Buffalo with a 416 Taylor because it deflected on some small brush before impacting.


.

Don't come hunting in northern ontario then....all our shotts are through area jsut like the pic....seen many a deer taken in the dense brush up here....

 

[Calum]

Don't come hunting in northern ontario then....all our shotts are through area jsut like the pic....seen many a deer taken in the dense brush up here....

Sounds like a dangerous place to hunt.

Perhaps this is why Ontario Hunters have to wear so much fricken Blaze Orange that they look like road construction crews.

Which I have never really understood as last time I checked some of the woods in some parts of Ontario are sporting Orange and Red leaves around the fall hunting season but I digress...

 

[archie_james_c]

Which I have never really understood as last time I checked some of the woods in some parts of Ontario are sporting Orange and Red leaves around the fall hunting season but I digress...

Nobody said we were smart...