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Brush Gun Test

02 Jan 2020
@ 08:49 am (GMT)

Magnus Vassbotn

Hi!


For a while now, I've been intrigued by the concept of a brush gun. Partly for practical purposes, and partly just out of curiosity. I've been contemplating a 9,3x62 in between my 30-06 and 45-70, to serve as a brush gun, and at the same time have a bit more practical reach than the 45-70. So this test was partly about finding out whether there is any point in getting a 9,3x62 (other than for the sake of just having one, a totally valid reason). Also it's interesting to put the 45-70 through some sort of test, rather than just get going at it and commence wounding.


I also wanted to put our 6,5x55 “meat load” through the test, as a friend of mine recently had a couple of incidents with it. He hit light brush on two occasions this season, causing tumbling. Both were on 90-100 kg deer (live weight), which is a very typical size here. Between us and a few more guys, we have now shot well over fifty red deer with this load, and it has performed very reliably within the 100-150 meters it's normally being used. But in these two cases, things didn't work out the way they should. One bullet hit sideways behind the shoulder, penetrating through the ribs and lungs, and stopping sideways against the opposite shoulder bone, killing the deer quite cleanly, but a bit slowly (luck). The retrieved bullet was almost unexpanded, and bent like a banana. In the other case, the bullet hit square on the shoulder, a perfect hit with good initial bleeding, but the deer kept going (limping) for an hour before the hunter got in a second shot to the neck. Unfortunately he wasn't there for the full “autopsy” of the carcass, and did not retrieve the bullet or examine the wound channel, so there is a degree of speculation in this case. We do know with a high degree of certainty that he struck brush a few meters before the deer, so we've concluded that the bullet must have hit sideways and stopped in the shoulder bone, never reaching the vitals. These two incidents are one of the reasons I wish to study the whole brush gun concept further.


I've tried to find some solid info/ experiences, but have found little more than established “truths” and stories of an animal here and there being shot through a bush, mostly right in front of the animal (I've done so too a couple of times). I also read the thread “Brush-buster myth” by Scott Struif here on the forum. It was interesting, with a lot of people sharing their views and personal experiences. It got me even more keen on doing a proper test, as I have yet to find any real, systematic tests on the WWW (though one comprehensive test from the last century was mentioned in that thread by Paul Leverman. Great if you could dig it up). The closest thing I've found is the “What is a Brush Gun?” videos (1 and 2) by Iraqveteran8888 at youtube (also mentioned in the thread). These test videos are very interesting and well made. The guy is entertaining, and clearly has good knowledge of guns and ammo. But the test is not going in depth, and is a bit lacking here and there. Specifically: No consistent point of aim, same brush being shot again and again (disadvantage to the first guns), random brush density from shot to shot, offhand shooting, not enough shots fired. Generally a lack of consistency or uniformity. Still, the test is interesting, and shows a pretty clear tendency towards heavy (and slow?) being better.


So, in this test, a friend and I put up a target (approx 1,5x1,5 m) with a large taped cross for aiming “around” the brush, and a 30 cm circle in the middle, resembling the vitals of an animal. We then set up a good, dense shrubbery of spruce branches, which pretty well resembles most our brush here in Norway. Juniper, birch and pine brush is much the same with regards to branch thickness and foliage/ needle coverage. The branches in our test were from 3-20 mm thick. The shrubbery was renewed/ re-aligned between every shot. We shot through the shrubbery from about 6 meters, and from there on, it was 20 meters to the target. This was meant to simulate a hunting scenario where an animal is standing at 70-80 meters, partly covered by brush. In such an instance, it's not always easy to tell whether the brush is 2 or 20 meters from the animal, unless you're able to range things up (which is rarely an option in the woods). Also, with a bit of distance between shrubbery and target, differences in dispersion becomes more clear. For other distances, one can probably just assume half the group size for half the distance and so on. The wild card is of course when the bullet passes through more than one bush on its way to the animal, but that's a project of its own.


Ammunition variables that I believe could have a profound influence on results are: Bullet weight, velocity, stability factor (SF), and bullet length to diameter ratio (perhaps LD? Length divided by diameter=LD), which of course is directly linked to terminal SF (low LD=high terminal SF). Regarding terminal stability versus external stability, I suppose there is a whole science and lots of established terms involved, but I haven't looked into it, and rely mostly on common sense, assumptions and the home made term LD. In this type of test, I guess external and terminal stability comes together in a way that is very hard to relate to in a proper theoretical fashion, as the bullet goes from external to quasi-terminal, back to external, and finally into true terminal ballistics.


Variables that I also believe could have an influence of their own are: Diameter, construction/ technology, material, nose/ ogive shape, sectional density (SD). When it comes to SD, I believe a high SD in itself is a good thing for brush busting, but not if it means a very high LD, compromising stability (small caliber cartridges). According to this theory, a 2-bore with short for caliber, yet very heavy bullets would probably rule the woods. But neither SD vs SF or any other variables were properly isolated and tested, so it's still just speculation. These things could be interesting to look at in a second, in depth test, with different bullet styles and weights etc. This test should be considered more of a preliminary test, just to see if the concept has merit, and also to take it one step further than the test by Iraqveteran8888.


The loads that were used follows under. They are all slow and heavy for cartridge-loads, intended for short ranges and minimum meat damage. Theoretical (external) stability factor is generated by the Strelok app.

6,5x55 – 160 grain Woodleigh PP @ 2475 fps. SF 1,88. LD 5,17.

30-06 – 220 grain Hornady Interlock RN @ 2450 fps. SF 2,62. LD 4,1.

9,3x62 – 285 grain Lapua Mega RN @ 1935 fps. SF 2,78. LD 3,36. This was an undeveloped safe-load, thrown together for the occasion. From the 20” barrel this bullet would normally most likely be loaded to about 2300 or so.

45-70 – 405 grain Woodleigh FP @ 1915 fps. SF 3,64. LD 2,24.


The first part of the test consisted of shooting 5 shots from each rifle through stacked up spruce branches with a good amount of needles and various sized sticks. There was a bit of randomness, with regards to sticks being hit or not, but we checked and renewed the shrubbery after each shot, so we got a good idea of what caused what.


As expected, the long for caliber (but still relatively light) 6,5x55 bullets performed poorly. None of them hit anything thicker than 3-4 mm on their way through the shrubbery, but they all tumbled and hit more or less sideways in the target. Group size about 50 cm. Considering this was mostly from going through needles, we saw no reason to test this load/ cartridge any further. All 5 shots were failures.


The 30-06 performed much better than the 6,5x55. 3 shots hit only needles, and landed in a 3 cm group at the center of the target. The remaining 2 bullets hit some pencil thick branches and tumbled fully and slightly, both still well inside the 30 cm circle. Total group size about 14 cm.


The 9,3x62 performed very similar to the 30-06, all things considered. 4 shots hit only needles, and sat in a 5 cm group at the center, one bullet keyholed slightly. The 5th bullet hit a finger thick branch, and landed 10 cm outside the circle, fully tumbled. Total group size about 27 cm.


The 45-70 performed very well. 2 bullets only hit needles, and sat 5 cm apart at the center. The remaining 3 bullets hit several pencil and finger thick branches with good resistance, but still landed within the circle. One bullet barely keyholing, another one slightly expanded. Total group size about 17 cm.


The second part of the test consisted of shooting directly through a finger thick stick, this time placed 23 meters from the target. For the most part, we had good, solid hits, but some were off to the side, usually causing more dispersion then direct, central hits. 5 shots from each rifle, except for the 6,5x55, which we ditched for this part of the test.


The 30-06 failed miserably. 1 shot only just inside the circle. 4 shots outside the circle, spread all over. 3 bullets tumbled. Total group size about 60 cm, and way off. Would have been lots of gut shots in a hunting situation.


The 9,3x62 performed just as poorly as the 30-06. All shots outside the circle, 3 of them tumbled. Total group size about 50 cm, and even more off than the 30-06. If it was a dear, one would have been lucky to hit a kidney, or unlucky and shoot off the front hoof.


The 45-70 performed pretty well. 4 shots inside the circle, and one shot 7 cm outside. Total group size about 34 cm. No bullets tumbled, but most showed some degree of expansion (larger holes). At least 4 shots would have been clean kills on a deer, the 5th one perhaps a marginal kill.


This is all the testing we could squeeze in that day, but it showed some clear tendencies. Some definite and unsurprising conclusions that can be drawn are:


1 – The 6,5x55 with this load is a poor brush gun. Tumbles easily, causing poor accuracy and penetration.

2 – The 30-06 and 9,3x62 with these loads will be thrown far off by finger thick branches. Tumbles and spreads.

3 – There is something to the concept of a brush gun. As logic dictates, the bigger the better. Every cartridge/ load has it's limit with regards to branch size, which in turn means that one could establish a more or less precise science or “recipe” around which cartridge/ load works for which brush density/ branch size.


Some less than definite, but quite likely conclusions to be drawn are:


1 – The 6,5x55 with this load will need a clear path, but like most cartridges, it will probably work through light brush if the animal is standing “in” the actual brush, giving the bullet almost no distance to tumble or veer off.

2 – The 30-06 and 9,3x62 with these loads can handle light brush, provided the animal is not very far from the brush. Little practical difference between the two cartridges.

3 – The 45-70 can handle light brush and small sticks/ branches, provided the animal is not very far from the brush.

4 – A combination of heavy weight, high SF and low LD is good.

5 – Brush busting will probably not justify the purchase of a 9,3x62 when one already has a 30-06. Damn...


One day we will delve deeper and get more data, shooting at least 10 shots with each gun through a more uniform shrubbery. Only needles/ leaves and 3-4 mm branches max. Than we will probably do at least 10 more shots with the 45-70 through finger thick sticks. Further finger thick stick testing is clearly pointless with the 30-06 and the 9,3x62, as 9 out of 10 shots were failures, and one just barely passed.


After this it would be natural to experiment with the different cartridges with different stick thicknesses and wood types, in order to establish where it all clearly goes south with all cartridge/ stick combinations. And then to see if there is any practical difference between the 30-06 and the 9,3x62, how big that difference might be, and how it will translate to real hunting situations. Then the next step would be to do the same with just one cartridge at a time, but with different bullets, and at different velocities. A hell of a lot of shots... I can't guaranty it will ever happen, but I will do one more test with the uniform shrubbery and more shots fired.


Even though there are a lot of variables and coincidences when it comes to shooting through brush and into a target, the same can be said about long range shooting with all it's predictable and unpredictable variables. And kinda like the reading, guessing, and estimation of wind speeds and wind patterns, perhaps one could get very good at reading and understanding brush variables and use science based on good statistics to take shots within the limitations of a particular cartridge/ load? For example, based on the very limited amount of shots fired in this test, one could feel confident about shooting a deer standing 10 meters behind a light bush, using a 30-06 heavy load, or an animal standing 10 meters behind a moderately dense bush, using a 45-70. Just a theoretical exercise for now, but at least it would be an interesting subject to play with, in lack of anything better to do out of season. If not for hunting purposes, then at least the knowledge could be used for target shooting through brush, which would most certainly make for a fine gentleman’s sport.


Some pics from the test:


Target with guiding tape


The top was trimmed down after the photo was taken


Shrubbery profile


Shrubbery front


6,5x55 through shrubbery


30-06 through shrubbery


9,3x62 through shrubbery


45-70 through shrubbery


30-06 through sticks


9,3x62 through sticks


45-70 through sticks


Sticks shot by 45-70



Shooting through sticks


Bullets used. 6,5/160 - 30/220 - 9,3/285 - 45/405





I hope this is of interest, and that it starts a frenzy of brush gun testing by other members.


Cheers

Magnus

Replies

02 Jan 2020
@ 09:44 am (GMT)

Nathan Foster

Re: Brush Gun Test
Hi Magnus, that was a very good read thanks. You did very well with both the testing and written work thereafter. It was good to see restraint, not becoming bogged down by theory or conjecture. A lot of practical, a bit of theory, some basic conclusions. Very nice.

Some time ago I was conversing with Dave Emary, Hornady's previous head ballistician, while writing my last book (SAWB). We were discussing barrier shots and Dave distilled his many decades of research and development into a single statement which made me chuckle - 'Bullets are unpredictable". I love that kind of honesty in the midst of so much reductive thinking. Focus on the practical and observe results, that is what really counts.
02 Jan 2020
@ 10:53 am (GMT)

Paul Leverman

Re: Brush Gun Test
Nicely done, Magnus. Almost identical to the article. I will start to search for the magazine and article this evening.
02 Jan 2020
@ 11:25 am (GMT)

Magnus Vassbotn

Re: Brush Gun Test
Nathan, thanks for the kind words. Much appreciated.

Paul, looking forward to the artickle. Thanks up front.
02 Jan 2020
@ 01:47 pm (GMT)

Mike R

Re: Brush Gun Test
Fantastic read Magnus
02 Jan 2020
@ 02:38 pm (GMT)

Scott Struif

Re: Brush Gun Test
Wow, Magnus! Thanks for the effort, and for posting the results of your research. I appreciate that you acknowledge the limitations of the 10-shot sample you used. Maybe Dave Emary, in the interest of science, would be willing to send you a case of .30TC for further testing.
04 Jan 2020
@ 08:27 am (GMT)

Ryan Nafe

Re: Brush Gun Test
Great post, very interesting to read. Thanks for the time and effort.
09 Jan 2020
@ 05:37 pm (GMT)

Paul Leverman

Re: Brush Gun Test
I found the article. It was in the 1987 Gun Digest Hunting Annual. Now the trick is to get it here. I will have to see which works better, scanning or taking photos and posting them. Authored by C. Rodney James, the article covers .22 rimfire, high velocity 22s, 30 cal., and 45 cal. bullets, as well as 12 ga. slugs, and 12 ga. shot patterns.

Bear with me while I experiment with the reproduction, I'll work through it as quick as I can.
09 Jan 2020
@ 07:13 pm (GMT)

Magnus Vassbotn

Re: Brush Gun Test
Great news Paul! I'm sure scanning will work. If it gets too small, then perhaps snapshots of sections? Looking forward to it.

And thanks everyone for your positive reception here. Gets me even more motivated for a more detailed test.

M
16 Jan 2020
@ 07:34 am (GMT)

Scott Struif

Re: Brush Gun Test
I wonder if the exposed lead tip of the 6.5mm bullets affected the outcome, vs the obvious conclusion that lack of momentum caused the lighter bullet's poor brush-busting performance. Hornady state in their paper describing the development of their heat shield tip that the nose of a projectile traveling 3000 fps heats up very quickly to 850 degrees Fahrenheit. The melting point of lead is 621 degrees. Seems like one could determine if the deflection is affected by the malleable tip being deformed by comparing SP vs FMJ bullets shot through a row or 2 of equally spaced 3/8 inch wood dowels set 1/8 inch apart in a block of 2x4. You could easily replace the broken dowels between each shot, and thus have a more or less controlled environment. Maybe I'll break down and get a .223 after all. I've got no use for one except to reduce practice costs. But what if FMJ bullets punch through brush better? Am I going to hunt with them?
16 Jan 2020
@ 09:37 am (GMT)

Magnus Vassbotn

Re: Brush Gun Test
I really don't know for sure, but none of the holes in the target gave any impression of signifficant deformation. The 45-70 showed expansion, but generally none of the other cartridges did.

The most obvious problem with the 6,5 was tumbling, so next time I'm gonna test the same bullet in round nose design. That bullet has the same weight as the PP, but is 3-4 mm shorter, resulting in a 30-35% higher stability factor, very similar to the 220 30-06. Also, I will be testing short flat nose bullets in 9,3 and 30, with very high stability factors. That way, I hope to determine if SF has any signifficant effect at all, or if momentum/ SD is more important. Of course, any difference in results could stem from the use of FN bullets, so I might do a comparison with shorter RN bullets after that if it seems meaningful. And then perhaps even heavier bullets off PP design, which is what I have available.

The reason I choose the FN design for the 9,3 and 30-06, is to try to mimic the 45/70 in both shape and SF as good as possible, to see how they all compare.

And as mentioned, more shots and more uniform shrubbery this time around. Just waiting for some deasent weather. Pissing rain these days..

M
16 Jan 2020
@ 01:16 pm (GMT)

Scott Struif

Re: Brush Gun Test
You've certainly piqued/renewed my interest in the subject. I hope to contribute to the research. Sounds like more fun than shooting groups all afternoon. It's raining nonstop here in western Oregon, too, and will be for the next couple months.
16 Jan 2020
@ 01:36 pm (GMT)

Nathan Foster

Re: Brush Gun Test
Hi Scott, I tested .308 147 FMJ in brush some years back. Deviation was very high.
16 Jan 2020
@ 05:26 pm (GMT)

Paul Leverman

Re: Brush Gun Test
Finally. Figured it out. Had to buy a new printer/scanner. Turns out it wasn't me, it was the technology (I always knew this). Anyway, there's eight pages, so each page will be a new post. I tried to get it as clear as I could. If you need to magnify the print, use the Ctrl key and your mouse wheel.

16 Jan 2020
@ 05:27 pm (GMT)

Paul Leverman

Re: Brush Gun Test
16 Jan 2020
@ 05:28 pm (GMT)

Paul Leverman

Re: Brush Gun Test
16 Jan 2020
@ 05:29 pm (GMT)

Paul Leverman

Re: Brush Gun Test
16 Jan 2020
@ 05:30 pm (GMT)

Paul Leverman

Re: Brush Gun Test
16 Jan 2020
@ 05:30 pm (GMT)

Paul Leverman

Re: Brush Gun Test
16 Jan 2020
@ 05:31 pm (GMT)

Paul Leverman

Re: Brush Gun Test
16 Jan 2020
@ 05:33 pm (GMT)

Paul Leverman

Re: Brush Gun Test



And there you have it.

Photos from an article "Brush Busting and Bullet Deflection" by C. Rodney James, 1987 Gun Digest Hunting Annual.
16 Jan 2020
@ 09:38 pm (GMT)

Magnus Vassbotn

Re: Brush Gun Test
Thanks for the huge effort, Paul. Very much appreciated!

This was a very interesting article. I like the mindset of the author. Also, it was interesting to see the comparisons between side hits and central hits on twigs, something I've been considering to test myself. But now I don't have to.

Also it was very interesting to see some tendencies towards very long for caliber bullets tumbling more easilly, the disatvantage nullifying or outweighing the benefits of increased weight. Something I will test more thoroughly.

The disappointing performance of the slugs might be partly caused by poor or varying stability from a presumed smooth bore. I doubt that the lead riflings on the slug can produce very consistent twist.

A couple of things that make this whole test a bit to light to draw any kind of conclusions that can be turned into practical advice for hunting, is the very low number of shots from each load (apart from 22lr), combined with the short distance from the target, making stastistical foundation and differences in dispersion too vague. I believe that in order to achieve something conclusive, one must first do very controlled tests and isolate variables, like here (but with more shots). After one has established the best load in each cartidge, one can set up a target behind an actual bush, and shoot an immense number of shots through the bush (to nullify differences in side hits/ central hits), always varying the shooting angle marginally beween each shot, as to not hit the same parts of the bush all the time. 10 shots through 4-5 different bushes into one target, from each cartridge. When there eventually is a 40-50 shot group from each cartridge to behold, one can draw conclusions relevant to practical hunting.

Any other ideas how to turn the testing into something useful we can actually act upon when hunting? Feel free to suggest!
17 Jan 2020
@ 12:24 am (GMT)

Paul Leverman

Re: Brush Gun Test
My pleasure, Magnus. I'm thinking that this was more of a demonstration than an actual "experiment", due to the many variables that you mentioned. The author was probably limited by his editors to how much space he had in the publication, forcing him to brevity. Still interesting though, and the article visually debunks some old myths, it might even get some of the "old school" thinking outside the box. Many thanks to you, as well, for bringing this subject to light once again.
17 Jan 2020
@ 08:29 am (GMT)

Scott Struif

Re: Brush Gun Test
Thanks to Nathan for his input, and to Paul for going to the trouble to make his archives available to us. Wow! Interesting stuff. As Magnus points out, it would take a fairly large sample size to draw any conclusions, but so far it looks to me like it's unethical to knowingly shoot through ANY vegetation, regardless of the projectile. My qualm now is, although a 243 is plenty of gun for the little blacktails I hunt, given that brush is often an issue, is a 243 less ethical than a 45-70? I secretly hope not. But, as Nathan said somewhere, you can't be over-gunned, as there's no prize given out for using the minimum caliber necessary for the job at hand.
 

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