My Scouting Efforts Paid Off!

[postoak]

Season opener was last Saturday. I hunted until noon at my primary site on both Saturday and Sunday, but saw nothing. I moved my stand to my secondary site (which was originally my primary site), on Sunday afternoon because it's got more deer traffic, but less oak trees, and since there are no acorns this year ...

I took off today (Friday), and was in my stand at 6:30. I went up 30 feet (which turned out to be too high for best visibility). At 6:45, I heard some loud splashing sounds coming from the creek, but couldn't see anything in the little bit of creek visible to me. It was so much noise I figured it was a group of hogs. At 6:55, I looked off to my right and saw a big-bodied deer walking my way from upstream; I couldn't see antlers, but the light wasn't real good yet. Then, I noticed right in front of my stand another deer, much smaller. I think this was an orphaned fawn, although I never got a good look at it.

Anyway, I waited and finally the big deer got into my shooting area. I looked at it through my scope and could make out antlers. Damn those ARs, I've hunted for 2 fruitless seasons, and now, my first deer and I can't shoot it! But, I kept looking and finally saw the off-side antler was unbranched. I wasted no time as it was about to enter an area where it would be hard to get a shot. I whistled to stop it. It didn't hear! So I whistled a little louder. Still didn't hear! I remembered I was wearing my game ears and whistled still louder. It stopped, but it's front end was screened by twigs and leaves. I knew my .270 would punch thru that stuff, so I guestimated where to aim and pulled the trigger. The 130 grain Winchester Power Point caused the buck to drop in its tracks. It was twitching quite a bit, however, so I gave it another shot, still having to guess my aiming point. That shot did the trick.

As I approached the buck, I got a little shock as it appeared to be a perfectly normal 8-pointer. But then I saw the off antler was deformed. It was only about half the diameter (or less) of the good antler.

This is the heaviest deer I've ever shot as I'm used to those smaller deer to the west. It probably field-dressed 90 or 100 pounds.

I'm confused about where I hit it. There was a 3 or 4 inch hole about 6 inches behind the shoulder on the side that should have been the entry side. On the "off" side was what looked like an entry wound! :confused:

I was also high with the shot and the back bone was broken, even tho the entry and exit holes didn't seem to indicate that the bullet should have gone that close to the spine. I'm confused about the whole thing. My second shot just cut a groove in the deer's cheek, about an inch below the eye. That was apparently enough to quiet it down, however, or maybe it was just coincidence.

Getting that sucker out was a chore. I pulled it about 15 yards and was tired. Remember, I've spent the last 35 years behind a desk. So, I got my game cart all the way back to the deer. That thing certainly paid for itself. It also helped me get the deer in my SUV. I stepped on the handle and raised the deer up level with the bed and then just slid it in.

I'm dead tired and it's nap time. ;) Tomorrow I'm off to the hill country with my 15 YO grandson for his first hunt, on my sister's place.

[Herne]

Your bullet hit the crud and tumbled?

So you got splash on impact and the exit is merely a fragment, and the rest of the bullet has gone all over the place hence the damaged spine?

Shooting through brush certainly makes for excitement. Still I'm glad you were lucky especially after a 2 year drought.

[postoak]

Wow Herne, what great detective work!

The "brush" was just some small slender branches, but the leaves made it hard to see. Still, this very well could have happened.

Yeah, I know you and some others will be critical, but when you haven't seen a deer for 2 seasons, this is the way you get -- or, this is the way *I* get.

[Altjaeger]

Congratulations. I know you have worked hard at hunting for that buck.

[Herne]

No I wasn't being particularly critical. Hell if I'd had a 2 season drought I'd have taken a shot at myself, never mind a deer.

You simply said you were confused about the evidence so I was offering an explanation. A single grass stem can topple a bullet, and we have all had these unexplained events - very often a headscratching miss. The problem really is that people genuinely believe that one can shoot through this stuff with any degree of certainty, and one simply cannot. And we ALL have the tee shirt. (Mostly its the fault of gun writers who drivel on about brushbusting with this round or that, etc and its just crap, cobblers and bunkum)

So no, I'm not criticising, and after 2 years I'm genuinely glad you were lucky, because lucky you were. But no matter - its in the freezer.

Would I have taken that shot - well with stuff in front of the target, assuming I couldn't have found a hole to go through, no I wouldn't. But then I never had a 2 year drought either. Nor did I have the situation where deer season is days long - I could always go out tomorrow and the day after that and the day after that, and that colours one's thoughts.

[Sabre]

Congratulations postoak ! You worked hard for that deer and should be very proud of your success.:)

[postoak]

Thanks, guys. I *did* work hard for it. I've never been as happy with a deer as this one, for that reason.

[postoak]

Here are 3 photos I took:

http://i411.photobucket.com/albums/pp192/want-to-be/th_IMG_0576.jpg (http://s411.photobucket.com/albums/pp192/want-to-be/?action=view&current=IMG_0576.jpg)

http://i411.photobucket.com/albums/pp192/want-to-be/th_Buck1-A2009.jpg (http://s411.photobucket.com/albums/pp192/want-to-be/?action=view&current=Buck1-A2009.jpg)

http://i411.photobucket.com/albums/pp192/want-to-be/th_IMG_0577.jpg (http://s411.photobucket.com/albums/pp192/want-to-be/?action=view&current=IMG_0577.jpg)

The shot went thru the lungs, so even without breaking the backbone, I don't think this deer would have gone far.

[venado]

Good going Postoak, those bucks you have to work hard for are valuable to the old memory bank no matter what sort of antlers they have. That entry wound looks like the old version of the 140 gr. ballistic tip out of my 7STW..!!

[ncboman]

Good job.

Venison time. :)

[Wismon]

Rock and roll!

Those Power Points are good bullets, I've been led to understand.

Congrats on your success.

[postoak]

Thanks. I've never used them before. At longer ranges I use Federal Premium Ballistic Tips. I bought the Winchesters off a guy who had sold his .270, and figured they'd be accurate enough at 35 yards even without me sighting in with them.

[Herne]

Thanks for the pic Postoak

Thats whats happened - that is a key hole entry so the bullet has tumbled having hit a leaf/twig or other obstruction - of that there is no shadow of a doubt. And for an entry that low, to break spine, it has spun upwards and almost certainly broken up in doing so. (Unless you were lying down below the deer :) )

Glad your luck held. - (but it would be unwise to draw any conclusions about performance or accuracy or future behaviour in brush on the basis of that one)

[Alan R McDaniel Jr]

PO, good going. That'll be one to tell that grandson about for a lot of years on "How to Hunt a buck".

Alan

[GF.]

That entry wound looks like the old version of the 140 gr. ballistic tip out of my 7STW..!!


Good Lord, man! And here I didn't like that bullet out of my 7-08! :eek: Might as well use an RPG.

Good hunting PostOak! Herne's explanation makes sense to me, so I think I'll double up on that note to self about not shooting through brush.... and I'm gonna be taking the scoped rifle whenever I'm feeling highly motivated to get one 'today'...

Even with the .45/70, I think I'll need a nice, clear shooting lane, and there's a limit to how far away I can see small twigs. Time to get the eyes checked, eh?

Funny thing... I checked your photo album and found this (check the thumbnail). Think they'll get a lotta donations? :D

[Bushman]

Outstanding Postoak, we have all been pulling for you after reading about all of your scouting efforts. The only blow up on an entrance that I have ever gotten was with an Accubond 140 grain out of my 7mm-08 and it made me think that those plastic tipped bullets just do that. That bullet went straight through though so I'll concur with Herne about a tumble. Power Points are fairly soft, but they act like "normal" cup and core bullets in deer.

On brush deflection, the worst bullet that I have used has been the 180 grain round nose Core-Lokt out of my .308. I like it in deer, but not on the range or in the brush. My own theory is that the rate of twist in the rifling has something to do with the stability of the bullet. That .308 has like a one turn in twelve inches while my 7mm's have one turn in nine inches and I have had less trouble with 7mm bullets staying on course. I am remembering the wound characteristics of those early AR-15's in Viet Nam where the twist was very slow for a .223 bullet and they tumbled when they hit.

[Herne]

Bushman the rate of twist with respect to bullet lenght and velocity has EVERYTHING to do with stability. And the longer and slimmer the bullet, the more likely it is to tumble.

Has to be a tumbled bullet - keyhole entry, so it hit the animal travelling sideways. There is no escaping that.

Broken spine, for a bottom of chest entry. Its hit low near the brisket, and gone up at about 80deg. And he was shooting from a stand I think, so his initial angle is downwards.

He's got an exit high, so that's where most of the lead core went.

He's got injury to the lungs so that's where the rest of the fragments went.

It may have turned through more than 80 degrees depending on where the initial point of aim was. If Post Oak could see the back half of the animal, and so it made it easy to work out the halfway POA, and thats where he was going for, the initial upset sent the bullet spinning down, and then on impact, tumbling, its shot off upwards though something nearer 100deg. Anyway, its done the classic. Spun out of control and the bending moment breaks the bullet up along its length.

Depending on exactly where the POA was with respect to that low strike you could have been mighty mighty lucky. Couple of foot further away from the leaves, and it could have missed clean and gone under altogether.

I hate blades of grass in the bottom of scopes, and skimming it over wheat fields, or thin twigs in the dark.

[Sabre]

I've read many "bullet deflection through brush" tests over the years. Most say any bullet will deflect with brush contact and based on my own testing that's absolutely true. However, my own testing indicates that some bullets are much more prone to extreme deflection even with very light brush contact than others. Light, fast, long, pointy bullets deflect easily and most radically. Slow, short, heavy bullets deflect much less radically. A .30-30 bullet is alot more likely to hit a deer after contacting a small twig or grass a few yards in front of the target than is a 243 bullet. The old fashioned Foster and Brenneke shotgun slugs fired from smooth bore barrels are better at getting through light twigs/grass without radical deflection than any rifle bullet in my experience.

[Herne]

Absolutely about rifle bullets. That's why all this bit about a 180 being better at brush busting than a 150 is so much misdirected rubbish. The greater the length to diameter ratio is, the more it needs to spin to remain stabilised and the more prone it is to tumble. And in the limit, a round ball is the least prone - to tumble. (but then you wouldn't know if it had tumbled anyway.) And for rifle bullets the shorter and lighter for calibre, the less likely to deflect - of course (or to be precise, since actual mass has little to do with it, the smaller the l/d ratio)

Unspun projectiles can still bounce of course, but that's a different mechanism from tumbling caused by spin instability. bounce needs something moderately solid. spin instability can be induced by a grass stem, or even incompressibility of the air at supersonic speed between a minor twig and the bullet. It doesn't have to hit it. All you need is yaw to be induced, and then your Euler equations say it must attempt to move at 90 degrees in the direction of rotation. Once it starts to do that, there is a very strong bending moment along the length under the turning forces induced by spin (rotational) energy, and the bullet will effectively snap in the middle.

Of Brennekes etc I have no knowledge but theoretically they should do a lot better, so if they do, then it proves the theory..(Well its not a theory actually )

[Bushman]

That is just one heck of an enormous entry wound though. It couldn't have happened any other way than what Herne describes, but I'm wondering if velocity has a lot to do with it. A bunch of years ago I had an 8 point come out at about 200 yards in some thick brush. I held for lungs with a 7mm RM with a 160 grain Nosler Partition. The buck dropped at the shot which I thought was a little odd compared to what I had seen that bullet do in the past. When I got to the deer I found that the bullet had hit brush and tumbled breaking the deer's neck. The hide showed a perfect sideways bullet keyhole shape, but no blow up like Postoak's buck. A 160 grain 7mm Nosler Partition is probably some tougher than a 130 grain .277 Power Point and my bullet was going slower at that point. Bullets do strange things sometimes.

[Herne]

Quite right Bushman. A tumbling bullet strikes as a keyhole. What happens next just depends on the jacket.

Military FMJs with a relatively thick jacket tend to break up less. Given enough room they will tumble because another factor is the density of the medium. The greater the density the more spin you need to stabilise. So with the 223, the bullet is made stable (just) in air, but on arriving in the more dense medium the spin demand rises and it tumbles. Sorry I digress.

Most of our big game bullets are relatively lightly jacketed so they bend and break, but it does depend on what that particular design will resist in a direction in which it is particularly weak - a few thou of copper isn't going to hold much together! The other reason why the bullet is likely to break up is because the initial yaw is in one plane, ie it swings nose to one side from the deflection, but the movement is 90 deg away, so it goes say down or up. Thus the bullet lies across the line of travel - hence the key hole entry of course - and the tendency to bend in flesh. Add in spin at 180000rpm and you can see why it goes pear shaped from just a blade of grass. Anyway, that's what's happening, but VERY FAST INDEED so its all difficult to predict.

The interesting thing is just what an angle these things will turn through in so short a distance, especially when velocity is some thousands of feet per second. Almighty g forces or lateral accelerations required to do that. (Velocity controls spin rate per unit twist.Impact velocity of itself doesn't have so much to do with it, because its angular momentum which provides the energy for this sort of stunt. )

Anyway, it makes the point about brush busting and firing though leaves, twigs etc. These rounds of ours are very very poor at it.

[Alan R McDaniel Jr]

There is no way of knowing what that bullet looked like when it hit the deer. Postoak is indeed lucky to have his deer. Even as far as shooting through holes in the brush, is a risky business. Just because you can see a hole through the brush doesn't mean that the bullet is going to go there. Unless there were circumstances like Postoak describes (2 yr dry spell) I'd not take the shot either.

I remember reading a story on this in either OL or FS when I was about 13 -14. (that woulda been in 68' or 69'. The writer built squares out of twigs laid parallel and tied to a frame and then shot through them with various bullets. As I recall the results of his tests were surprising and contrary to what one would think would happen. As expected, he could not predict with any certainty where any bullet would strike after hitting the twig array. Even with the same bullet the angle of deflection was always different. The most surprising result was that pointed bullets deflected less than round nosed bullets of the same weight and velocity. If you think about it for a moment this idea does not seem as unreasonable as we first like to believe. If I were to throw a football at a grid made of something that a thrown football could break through I'd likely get a fairly straight passthrough due to the point on hit and the spin of the ball. Now I take a round ball (volleyball) and throw it with the same velocity at the grid. There is greater frontal surface area to contact the grid, more forces acting on the ball and the lesser likelihood of a straight passthrough.

Now, try an arrow and a ball bearing. There's that length to weight thing in spades.

Wow, maybe maybe not, but those were his results anyway. Now with that said, there is no doubt that a round nosed bullet will travel straighter through a substance of uniform consistency than will a pointed bullet.

I wish I had the time and/or inclination to check these things out for myself, but, I don't. So I will have to be content with not shooting through brush.

[Alan R McDaniel Jr]

I almost forgot my Nosler Partition problem. I've told the story before so I won't tell it again, especially since I can remember telling it. If I couldn't remember telling it before I would tell it again. Long and the short is that nose lead slung off laterally (almost perpendicularly) to the flight of the bullet and the rear core traveled straight through. Same principle, in effect except that instead of twigs it was muscle and bone.

Alan

[Herne]

Alan - the problem with the football, arrow type of example is that they are not representative because they are not spinning, and it is the spinning bit that drives the turn and tumble.

All the initial deflection on leaf or twig does is induce yaw. Then I think it is the Coriolis effect kicks in and that makes the bullet move at 90 deg to the force and in the direction of rotation (same as helicopter rotor blades or a kiddies top). Anyway, stuff that lot through the euler equations for an object with 6 degrees of freedom, and you get yaw, a resultant direction and a tumble. But it HAS to be spinning to start with.

So the spin which we rely on for stability, is the same force that drives the thing haywire in the wrong circumstances. So you cannot compare a volleyball or whatever. Thats just straight reflection and momentum and bounce. This is angular momentum, and the bullet has quite a lot of it, being converted into a violent force or acceleration in a different direction. Thats why it is so steep and that's why it can turn through 100deg in a few inches, even at a velocity of x thousand fps. A musket ball can't do that - a non spinning object is just a different snooker ball. This isn't.

[Alan R McDaniel Jr]

Our "footballs" spin when throw and/or sometimes kicked correctly. One can and often does add substantial spin to a volleyball although they are not thrown. At any rate I will refer back to the fellow that did, in fact, write about the tests he ran and his results. All else is speculation.

I will see if I can dig up a video that I viewed recently of various bullets striking what appears to be steel plate at right and various other angles. It may not add anything to the discussion other than interesting viewing. It also shows projectiles striking other projectiles in flight.

Alan

[Alan R McDaniel Jr]

http://www.techeblog.com/index.php/tech-gadget/1-million-fps-video-of-bullet-impacts


Personally I don't think the rate of spin is much of a factor in the angle of deflection on a twig or leaf, there's just not enough time in contact and the amount of spin is negligible for the duration of that contact (except in my Nosler Partition problem, and there only because of the thickness of the object hit [deer's body]).

Alan

[Alan R McDaniel Jr]

I've got a one inch plate I shoot at that #1 son set up at 150 yards. It swings from the top. There is no doubt when a bullet hits it. I have always wondered why I could not find anything other than bullet fragments, even from cast bullets. Then I watched that video.

Alan

[postoak]

Yes, I was up 30 feet and the deer was at 35 yards, so there was a good downward angle. The bullet struct 3 or 4 inches below midpoint, then angled up dramatically to break the spine, and then one piece angled down somewhat and exited about 5 inches above the midpoint. The exit hole looked like your typical entry hole.

[Alan R McDaniel Jr]

Oh, Herne, arrows spin too. The vanes are set to cause spin. An arrow will deflect dramatically because of the length.

Alan

[Herne]

Nope - sorry. Arrows footballs and volleyballs spin slowly. Arrows are drag stabilised and depend on the position of the CP WRT to the CG to maintain a positive static margin. (ie move the CG fwds with a heavier head and accuracy will start to drop off - and beyond a certain point stability will go completely) We are talking of rates of spin required to stabilise, in the order of 150,000 rpm or more. For a 1/10 barrel at 3000fps the spin rate is about180,000rpm. We are talking of a different league.

Spinning a football or arrow simply causes the effects of aerodynamic inequalities and differences in the position of the CG from the true centroid to be evened out - and beyond a small point, small differences in air pressure on one side induced by rotation can cause a deliberate curve in flight. But its NOT about stability,

The rotational energy of an arrow or football is so small that it can be neglected in most calculations.

As for deflecting because of touching a leaf. No it doesn't - very little. Agreed. But what that does is impose a small amount of yaw, at which stage the spin energy takes over, and it will yaw further, and pitch nose up nose down, and also move nose up or nose down. Very violently, to the point that it starts tumbling, in nanoseconds.

That is very elementary mechanics and there is no getting away from that.


______

Destruction on a metal plate. Depends on the angle of impact, but basically the bullet crushed, the lead liquefies and the copper shatters and is spread about by the expanding lead. In a deer this doesn't happen because of the cooling effect of the blood etc, and it doesn't stop so the energy absorbed by the bullet is much less. (work done on the bullet)

What happens to the plate depends on what type of steel it is (and how thick it is)and what its heat treatment was. There is a shear plane set up, and there is a shock wave set up which reflects off the back surface. So the plate can scab or spall, be dented, or shear through and permit penetration.

-----------

An RN should deflect less. Its shorter for the same mass so its effective length is shorter and its l/d ratio is less. this stability is pretty marginal. A lot of heavy for calibre bullets will only remain stable out to about 5-700yards before they run out of spin and tumble in air, whereas shorter bullets are stable throughout. IRRC the 500 yard margin applies to the 1280 308 bullet from a 308 Win, while the military 162 grain goes on forever. The 257 120g bullet is only good (at 1/10 out to about 500 yards. There is not a lot in it.

[Alan R McDaniel Jr]

Oh, OK.


At any rate I will refer back to the fellow that did, in fact, write about the tests he ran and his results. All else is speculation.

Alan

It really doesn't matter to me why it's not a good idea to shoot through brush, leaves, twigs or steel plates, I'll just continue to not do it as a rule. I presume you will also. I was surprised to learn, from this one set of tests, that the pointed bullets deflected less. Why? There's a whole bunch of stuff in this world that I just look at say "Wow, would you look at that!"

Spin is spin regardless of where that spin is imparted. The bullet and the football get their spin initially and the arrow gets it's throughout the flight. It's the same stuff and is there to stabilize the projectile.

This kind of discussion makes me mad enough to get up and go hunting!:D

Alan

[Alan R McDaniel Jr]

Here's one test.


http://www.theboxotruth.com/docs/bot40_5.htm

Alan

[Herne]

No its not.

By all means, if you have that theory, go to the military and start expounding on fin stabilised projectiles and long rod penetrators.

In the one case we have a rotational kinetic energy store which is suddenly released by the introduction of yaw, as basic mechanics says it must - its only an extension of equal and opposite reaction and Isaac Newton.

In the other cases we have drag stabilised projectiles stabilised by by the position of the CP with respect to the position of the CG - the positive static margin. Arrows - if you don't beleive me, take the fins off an arrow, and try to spin stabilisie it and see how far you get - about nowhere.Try moving the CG about on your caravan - load it tail heavy, CG moves back, CP remains steady, caravan wobbles all over. Same maths.

Footballs/rugby balls. Yes a slow amount of spin will tend to keep the thing point on, but the reason for it is aerodynamic and not kinetic as we are discussing. Under many circumstances a rugby ball will actually fly perfectly true and without tumbling, without spin - when kicked for instance - which a bullet will not, ever. (L/d ratio) What is a well thrown rugger ball spinning at - a couple of hundred rpm. We are talking of 150,000, so any of the oval balls simply do not have that rotational kinetic energy, either to stabilise them effectively (on its own), or to make them turn so violently if peturbed in flight.. (the stability comes from the movement of air and skin friction, rather like golf ball dimples, and the fact that it evens out the errors around the true centroid - as does slow spin with arrows and any other drag stabilised projectile.)

We are not even in the same region of Re.

We are talking about entirely different mechanisms - you will just have to trust me on that.

(Do the maths Alan - you have an object - a football. It has a moment of inertia, it has a rotational velocity in radians per sec, you know the mass. You don't need to take socks off to see that the rotational energy is tiny - a few joules.)

[Alan R McDaniel Jr]

Well then ......What's better a 270 or a 30-06???? hunh? answer that for me Mr. Smarty Pants! Please don't destroy my fantasy world based on superstition and supposition with a a bunch of facts! I'm going to start calling RNs "Brush Busters" if you don't stop!

I think the military already has some of those little finned projectiles and long rod projectiles anyway.

As far as golf balls go. I believe there are little demons living inside of each one causing them to seek out trees, sand, water and impenetrable brush.

Relax Herne, it's Sunday morning, or evening for you. I trust your experience and knowledge. It's seldom that you haven't done your homework.

Alan

[GF.]

Found a nit to pick....


Arrows are drag stabilised and depend on the position of the CP WRT to the CG to maintain a positive static margin. (ie move the CG fwds with a heavier head and accuracy will start to drop off - and beyond a certain point stability will go completely)

Moving CG forward... we call that FOC (Forward Of Center), meaning that's where the CG/balance point is, typically expressed as a percentage. And the emphasis, whenever the subject comes up, tends to be on getting enough of it, rather than too much of a good thing.

In fact, there's a fellow named Dr. Ed Ashby (I have no idea where he got his doctorate or in what, but whenever his name is invoked, 'tis done so with an air of gravity, and the traditional archers make sure to use the title ;) ) Anyway, he's constantly fiddling and testing with broadheads, and one of his key elements in getting huge amounts of penetration is what he refers to as 'extreme FOC' (his preferred test medium is buffalo - the big, all-black, genuinely evil-tempered kind).

Anyway, from a flight stability aspect, I've always reasoned (rightly or no) that moving the FOC forward has an effect comparable to increasing the size of the fletching; that being, more force exerted on the aft end relative to the fore - so smaller fletchings can accomplish the task just as well as larger ones, given a longer lever.

Take that to an extreme, and no fletching at all should be required. And in truth, that works out fairly well, unless you're using a broadhead. Put the fins on the wrong end, and Very Bad Things can happen! And even with a target point, part of me wonders if you can't get too much of a good thing and allow a fletching to cause an unending string of overcorrections which could scrub off speed unnecessarily...

So perhaps the 'extreme FOC' really only works best for penetration purposes, and does so because of the need for greater arrow spine in order to launch the shaft stably - substantial inertia up front means you need a lot of stiffness along the full length of the arrow when pushed from all the way back at the nock. And then on impact, you have a very much shorter working length of shaft between the CG and the point of resistance, so the arrow won't flex much at all on impact, and that keeps it going straight-line all the way through. And for that matter, even if I'm mistaken about the importance of the distance from CG to point, you still have a stiffer arrow end-to-end.

But of course, your point was about accuracy, rather than stability, so maybe I'm mixing two different kettles of fish ;)

And I do know that arrows can't be relied upon tofly terribly straight after they've bounced off of anything mid-flight. Yes, they'll straighten up nicely flying in their new direction, but the original bearing gets lost pretty quickly...

[Altjaeger]

Well while you guys argue all the esoteric truths of ballistics and physics I think I will just take 3 of my rifles to the range and make sure they are hitting where I point them. I head out on another trip Tuesday and have decided to take different rifles this time. :)

Yup. I know Herne!:D

[GF.]

Something I do know for sure - get me a shot much past bow range, and I'm better off shotting the scoped 7-08 through the holes I can see in the brush, rather than using the irons on the .45/70 and hoping to shoot through the holes that I think I can see in the brush :D

[Bushman]

Alan's video shows blow back very well. That is something else that could explain a much larger than expected entrance wound. One of the biggest surprises that I had when shooting green colored water filled plastic gallon milk jugs 18" over snow was that a lot of the spray was coming forward, back toward the shooter. The spray pattern was like a cross forward and backward and off to both sides. On a deer it probably happens more when a bullet hits a more solid area. A friend of mine used a .30-06 and a hot loaded Trophy Bonded Bear Claw to shoot a buck in the shoulder. He was telling me that the wound channel looked just the opposite of what you would expect. It had a big entrance wound and a smaller exit wound. I saw that too with an Accubond on a close shot with my 7mm-08. Postoak's 130 grain Power Point at 35 yards from a .270 was very fast with a thinly jacketed bullet and it might have broken up on a rib going in and deflected causing multiple wound channels.

Alan's video also shows why I got hit in the head from 25 yards standing behind the shooter watching a steel silhouette shoot. I won't do that again without eye protection.

On the brush deflection with a round nose Core-Lokt that I have experienced, I'm wondering if the softer, much larger amount of lead exposed at the tip "caught" more brush than my pointed bullets have? Nothing scientific, just observation over lots of years of hunting deer in the thick stuff.

[Herne]

Matt- my apologies for bad proof reading - and you are dead right.

It should have read if you move the CP forwards. ie if you move the aerodynamic centre (CP) forwards and I was assuming a bigger heavier head meant bigger vanes ie there was an aerodynamic penalty. (Probably that's why some broadheads have outline edges - no solid centre, so you can create a wound channel and maintain aerodynamic integrity)

Ideally with any drag stabilised device you need the CP as far BEHIND the CG as possible to create a +ve static margin. Therefore for flight characteristics a tungsten head of the same diameter as the shaft would be optimal - but then it possibly wouldn't do as much damage to the target. (See above)

The reason is this. Assume the arrow starts to yaw- on a vertical axis through the CG. OK, the tail comes out and presents side area to the airstream. Air pressure acts through the aft CP, creating a restoring moment, pushing the tail inwards towards straight.

The moment = 1/2 air density x velocity^2 x surface area x sin alpha (alpha = the yaw angle) x the distance CP- CG. This is acting behind the CG so, just like a caravan on tow with a fwd CG it is self damping or converging.

Now change the design slightly, to get the CP in front of the CG, and the force still acts in the same direction, and it is of the same same magnitude since side area and yaw angle are unchanged, but now, instead of taking the tail in, it will take the head OUT - ie it is diverging and unstable. Sketch it out, and you will see exactly what I and I expect Dr Ashby mean. And don't load your caravan so the CG is aft, next hunting trip, or you'll experience divergence at first hand!

(note the force will be the same, other things being equal, but the size of the moment (torque about the CG) depends on the distance CP to CG, which might not be the same)

My apologies- fortunately the sense the rest of the posts is not compromised, and getting it right makes it clear - the difference between spin (gyroscopic) stability, and aerodynamic stability. Getting a bit carried away.

[Herne]

Blow back.

1. Shoot at a steel target and of course, if you get an impact at the perpendicular, then it will bounce straight back.

2. You can explode anything if the outer jacket is weak enough. Like any balloon, pressure is exerted in all direction in theory.

3. We aren't shooting at things with weak skins and of a relatively small size. So in the real world of bigger game blow back is hardly likely to feature.

(In the limit, shoot at a 44 gallon drum, and see how much "blow back" you get. Nil bordering on nothing - you get a neat little hole.

Put not your faith in ballistic gelatin and 1 gallon plastic cans. They are very good at telling you how ballistic gelatin and 1 gallon thinwalled containers behave given a high speed strike, but other than that they are pretty useless, except possibly to varmint hunters and exploders of 1 gallon cans.

If you want to get something useful, you can do what the military does - shoot at VERY large blocks of gelatin, (for comparative trials which need a control) or use pig carcases. For the rest of it it is a complete waste of time.

In the case of Postoaks shot, all is very plain. The bullet hit a leaf, the bullet yawed and tumbled as a consequence. Fortunately it hit the target in a lethal spot, and since it was spinning, it then ricochetted upwards doing more fatal damage. Its no more complicated than that.
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Finned projectiles - yes, did a lot of the trials on the early DU ones. Trundled them for bloody miles to try to damage them and then did the firing trials to prove accuracy. Tips make good coat-hangers in a turret.

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There'm a lot more to the dimples on a golf ball than you might think - but thats another story. :)

[Alan R McDaniel Jr]

There'm a lot more to the dimples on a golf ball than you might think - but thats another story. :)


You should see them when I'm through with em!

Alan

[Herne]

I always stayed away from them too.

Straight has no meaning in my golfing vocabulary.

I can shoot OK, I can cast a fly, dry or nymph, and get it on a trouts nose or down to depth, without dragging on a cross current, I can even do a Leisenring lift, but I cannot hit a golf ball. Not even not straight.

But dimples I know about. And those ones as well.

[Altjaeger]

I played a few rounds back in the 70s. After spending more on lost golf balls than on greens fees a few times I decided I better stay to hunting, shooting and camping. :D

[Alan R McDaniel Jr]

I play golf three times a year just to keep up on my game.

Alan

[Twanger]

Nice buck poastoak!
It seems to be the year for odd-horned bucks.
I shot a 4x1 earlier, and my buddy tracked and recovered one with three beams. We have 4 bucks runnning our neighborhood that are 4x0,4x1,or 4x2.

[postoak]

At least we can't blame these on the new nuclear powerstation in the neighborhood -- since there aren't any (yet, I hope).