Bullet Penetration Question

[Gatehouse]

I was going to order up that test tube thingie but decided that I would end up becoming obsessed with it, loose out on valuable hunting/fishing time only to find out what I already know about my favorite bullets. Ones that I have tested before and used successfully on game.

Easy to get obsessive when playing aorund wiht bullets and guns.

I have to admit, I like doing that stuff but honestly could hunt and kill everything, for the rest of my life, with a 270/30-06/7RM/300 and TSX bullets, and not bother with any of the silly stuff like making 30-30 Winchester Short Magnums etc.

 

[Dogleg]

The bullets in this discussion are all lead-copper construction, with one bonded. Since the potential advantage of the bonded bullet not coming apart is negated by none of the bullets coming apart, that little detail can be ignored. Sectional density of an expanded bullet can also be calculated and compared to other expanded bullets as well.

 

[John Y Cannuck]

I know from past discussions that everybody that has posted on this thread understands that SD is only relevant when comparing bullets of the same construction.


I was going to order up that test tube thingie but decided that I would end up becoming obsessed with it, loose out on valuable hunting/fishing time only to find out what I already know about my favorite bullets. Ones that I have tested before and used successfully on game.

Yup, a very reasoned argument!
X2!

 

[Omega]

OK, back to softs, though the TSXs you like to mention act a lot more like solids than you think. How do you explain that bullet after bullet is found against the hide, point on? A large exit hole only proves that the permanent cavity is larger than the bullet. A round hole that is the size of the bullet or smaller can show quite a bit. A long shanked bullet like a TSX that is going sideways through thick hide cannot make a round hole that is more or less caliber sized. It simply cannot, yet they seem make tiny little exit holes that taxidermists love. Even arrows going through paper leave tell-tale tears that show when they are not traveling straight. I've skinned a few too many animals shot with TSXs to think that the bullet was tumbling on exit, although I'm certain that some do, sometimes. The one TSX that I'm certain tumbled never exited.

And how do you know what went through the hide first, the nose or the butt?

 

[Omega]

After shooting hundreds of bullets into PermaGel there is no doubt in my mind that expanding bullets tumble or actually roll if I read the path through the gel right. There is a minimum amount of expansion required for the roll to occur and I've never had a Barnes bullet expand enough to stay in 35 inches of gel. Their paths are straight through. Every bullet that expands to twice its caliber or larger rolls. Center of balance has nothing to do with it and friction of the gel has everything to do with it. A bullet that expands this much is wider than it is long and the effects of friction take over causing the bullet to take the cleanest path which is the tumble or roll. It continues on in a straight path as described by Newtons Law. To think you can tell caliber by a hole in the hide is laughably absurd.

 

[Dogleg]

And how do you know what went through the hide first, the nose or the butt?

Omega,
A bullet could exit base first, yes. It if it were tumbling it could exit in an infinite amount of positions from nose on, sideways or base first. Since probability vastly favors a tumbling bullet hitting the hide sideways to some degree there should be evidence of this. The chances of bullets hitting only point on or base first if it were tumbling on more than one plain would seem to to be very slight. Since the majority of bullets that I have recovered were still facing nose first, I have no reason to believe that all those that exited were reversed, or tumbled.

Who claimed to be able to tell caliber by exit hole? You should learn how to read. You should get Mr. Newton to explain how to get bullets to fly straight through brush, a little detail the shooting world has be struggling with.Small twigs will deflex bullets, and a straight path through an animal is by no means assured. The most dramatic example I've personally seen happens to be a TSX that I stuck into a buffalo. The shot was 20 yards give or take a pace and placed exactly behind the shoulder. The bullet was found in the hind-quarter, which pissed me off as well as the buffalo. Straight penetration would have been appreciated, and would have resulted in one shot instead of 3, plus a 4th finisher.

 

[Omega]

Omega,
Who claimed to be able to tell caliber by exit hole?

Why you did in you claim that you can so exactly read the holes in the hide that you can determine the aspect of the bullet upon exit, ergo you must be measuring caliber to be so exact.

You should learn how to read. You should get Mr. Newton to explain how to get bullets to fly straight through brush, a little detail the shooting world has be struggling with.Small twigs will deflex bullets, and a straight path through an animal is by no means assured.

No, you are the one that needs to learn how to read. Go back and struggle through Newtons first law of motion. In it you will learn what I am talking about and discover what those little sticks mean to the flight of the bullet and the difference between that and a bullet in media... Were there a bone in the media to create "external force" (see Newton's First Law of Motion) then the bullet direction would change.

 

[Boomer]

After shooting hundreds of bullets into PermaGel there is no doubt in my mind that expanding bullets tumble or actually roll if I read the path through the gel right. There is a minimum amount of expansion required for the roll to occur and I've never had a Barnes bullet expand enough to stay in 35 inches of gel. Their paths are straight through. Every bullet that expands to twice its caliber or larger rolls. Center of balance has nothing to do with it and friction of the gel has everything to do with it. A bullet that expands this much is wider than it is long and the effects of friction take over causing the bullet to take the cleanest path which is the tumble or roll. It continues on in a straight path as described by Newtons Law. To think you can tell caliber by a hole in the hide is laughably absurd.

What you are observing in the tract of the gel is from the rotational velocity of the bullet, rather than bullet that somehow has tumbled while penetrating the gel. While the bullet passes though the medium at a super-sonic velocity, there is no physical contact between the bullet, once that bullet has expanded, and the target medium, due to the shockwave that is projected forwards and envelops the bullet until the velocity becomes subsonic. Upon becoming subsonic, there is friction between the bullet and the gel, and the bullet tract narrows to equal the expanded diameter of the bullet. At no time after the expansion of that bullet, provided it retains its integrity, can it do anything but penetrate in a straight line in a fluid medium. While at super-sonic velocity the bullet's shock wave displaces the medium it passes through, and once sub-sonic, it's center of gravity keeps the bullet facing nose on. The 380 gr .375 Rhino bullet displays the greatest amount of expansion, relative to its original diameter, of any bullet I've tested. Other than when it failed to expand due to being fired into a dry medium, penetration has never been anything but nose on.

Solids, by contrast, need to have parallel sides and be short in length to ensure straight-line penetration. The shock wave that envelops the expanded bullet during it's super-sonic penetration is less efficient with a solid, although a flat nose appears to help, so there can be friction between the super-sonic bullet and the target material in this case, and that can effect the stability of the bullet during penetration of the target material.

 

[Omega]

What you are observing in the tract of the gel is from the rotational velocity of the bullet, rather than bullet that somehow has tumbled while penetrating the gel. While the bullet passes though the medium at a super-sonic velocity, there is no physical contact between the bullet, once that bullet has expanded, and the target medium, due to the shockwave that is projected forwards and envelops the bullet until the velocity becomes subsonic. Upon becoming subsonic, there is friction between the bullet and the gel, and the bullet tract narrows to equal the expanded diameter of the bullet. At no time after the expansion of that bullet, provided it retains its integrity, can it do anything but penetrate in a straight line in a fluid medium. While at super-sonic velocity the bullet's shock wave displaces the medium it passes through, and once sub-sonic, it's center of gravity keeps the bullet facing nose on.

Uhhh, explain this please. I'll borrow a photo from a friend who posts them for me.
http://www.theoutdoorquest.com/images/Ballistic-gel-250-SST-and-3.jpg
There are two bullets there and once expansion is done at around eight inches of penetration the bullets tumble or roll as you can clearly see here neither are facing forward (left) after about 23 inches of penetration. After about 8 inches the bullet is subsonic in the gel and friction of contact with the gel causes tumbling to start. Since I can't see inside an animal I can't comment however Dr. Fackler HAS seen inside many animals studying bullets and wounding actions and states that tumbling of bullets is a huge source of tissue destruction. You might want to Google that name if you are interested in bullet performance and wounding studies.

Solids, .

Please I've said nothing about solids, bullets just about always must expand to tumble in gel.

 

[Boomer]

Fackler may of been referring to tapered, non-expanding bullets which often tumble during penetration as their center of gravity is at the rear of the bullet. In a human or animal body certainly impact with bone can effect both straight-line penetration and the stability of a bullet that is not completely stable. This is seldom the case with a bullet intended for use on big game, because the bullet makers realize how important straight-line penetration is.

I can't comment at any length on the picture in the link due to the fact that it makes little sense. How is it that two bullets have formed but a single tract in the gel? Perhaps it is a single bullet that has broken in two or a bullet that has sprued it's core. But if two separate bullets, why fire them into the gel in such a way that their individual tracts are not visible? There is no evidence in the picture of the passage of a super-sonic bullet.

 

[Omega]

Fackler may of been referring to tapered, non-expanding bullets which often tumble during penetration as their center of gravity is at the rear of the bullet. In a human or animal body certainly impact with bone can effect both straight-line penetration and the stability of a bullet that is not completely stable. This is seldom the case with a bullet intended for use on big game, because the bullet makers realize how important straight-line penetration is.

I can't comment at any length on the picture in the link due to the fact that it makes little sense. How is it that two bullets have formed but a single tract in the gel? Perhaps it is a single bullet that has broken in two or a bullet that has sprued it's core. But if two separate bullets, why fire them into the gel in such a way that their individual tracts are not visible? There is no evidence in the picture of the passage of a super-sonic bullet.

hehehe you do like playing dense don't you? Obviously the bullet paths while in a line on one dimension aren't on the second plane, when viewed from above the two paths are visible. But I'm sure you knew that before your comment - nobody who shoots is that stupid. You do see that one bullet faces the camera and the second or rear bullet faces away.
Perma Gel blocks are 17 inches long as I said above these bullets are at 23" so they are into the second block. The evidence of super sonic is displayed in the first 8 inches of the first block but if I showed the entire path you'd complain that the bullets weren't visible, I do know your kind.

 

[Boomer]

I think I'd have taken the picture to show both bullet tracts, interesting that they lie on exactly the same plane. You are not very forth coming with the make, caliber, style, or weight of the pictured bullets; any reason for that? If you are going to make a case for a particular argument and present evidence to support your argument, any holding back of pertinent information becomes suspect. I don't have any axe to grind, because I know how bullets work.

Edited to add . . .

I keep looking at the first bullet in the block and I'm attemtping to visualize what bullet might expand so that the jacket leaves a wide skirt below the lead core with no shank visible. All that comes to mind is a hollow point pistol bullet, which would explain alot. If you know what the bullet is, I would like to know.

 

[470 Mbogo]

I looked at the picture of the bullet traveling in the gel and can't see any tumbling. All I could see is a very poor bullet basically blowing apart loosing it's core and fragmenting. Bullets do not normally tumble. With the very high rpm a bullet is turning and the fact the shorter the bullet becomes the more stable it become it's pretty hard for it to turn end for end. Yes it has and does occasionally happen but it is very rare in modern bullets.

Look into this link to see what normally happens.
http://www.barnesbullets.com/ Check out thew video that Barnse has put together and it is pretty much how it is.
Take good care,
Dave

 

[Omega]

I think I'd have taken the picture to show both bullet tracts, interesting that they lie on exactly the same plane. You are not very forth coming with the make, caliber, style, or weight of the pictured bullets; any reason for that? If you are going to make a case for a particular argument and present evidence to support your argument, any holding back of pertinent information becomes suspect. I don't have any axe to grind, because I know how bullets work.

Edited to add . . .

I keep looking at the first bullet in the block and I'm attemtping to visualize what bullet might expand so that the jacket leaves a wide skirt below the lead core with no shank visible. All that comes to mind is a hollow point pistol bullet, which would explain alot. If you know what the bullet is, I would like to know.

The left bullet is a 50 cal 250 grain SST fired from a muzzleloader at 2250 fps, the bullet to the right is a 220 grain Hornady Interlock shot out of a 375 H&H at 2854 fps.
The picture was taken as it was because of the striking aspects of the bullets, the paths were unimportant to the issue at the time.

 

[Boomer]

I guess it doesn't pay to drive those Interlocks beyond their design parameters, huh? You can see from the tract that the SST dipped just a few inches before coming to a stop, so 99% of it's penetration was nose on. I obviously cannot tell where the 220 gr .375 bullet dipped because the tract is covered up. Suffice to say that very low bullet weights will not give optimum performance where deep penetration is required, although I'm impressed that the penetration was a straight as it was given the light for caliber bullet weights. Those straight bullet tracts also indicate that the penetration of both bullets was nose on, because when a bullet tumbles at velocity the path is erratic.

 

[joe-nwt]

Good reading, gents.

 

[Dogleg]

Why you did in you claim that you can so exactly read the holes in the hide that you can determine the aspect of the bullet upon exit, ergo you must be measuring caliber to be so exact.

No, you are the one that needs to learn how to read. Go back and struggle through Newtons first law of motion. In it you will learn what I am talking about and discover what those little sticks mean to the flight of the bullet and the difference between that and a bullet in media... Were there a bone in the media to create "external force" (see Newton's First Law of Motion) then the bullet direction would change.

No, I said that I can sometimes tell the difference between a straight penetration and a keyhole,no measuring is required for that providing that there is something left to look at. Are you and sheephunter testing pistol bullets in muzzleloaders and trying to make it apply to all bullets?

 

[Omega]

No, I said that I can sometimes tell the difference between a straight penetration and a keyhole,no measuring is required for that providing that there is something left to look at. Are you and sheephunter testing pistol bullets in muzzleloaders and trying to make it apply to all bullets?

*Sigh* Sunday an off day for you is it? Try reading the post above that made hours before yours.

 

[Omega]

I guess it doesn't pay to drive those Interlocks beyond their design parameters, huh?

Would you like to see a Trophy Bonded Bear Claw taken from the same media? Every make of bullet that expands is turned to a big mushroom. The Perma Gel is a tough ride for a bullet, much tougher than an animal with no bone hit.
I have a big shipment of Barnes and Nosler E-tip coming, I've got 70" worth of gel set up so I will trap the bullets this time. My thoughts are the long for weight bullets won't do it. The bullets need to expand to a short shanked mushroom profile and I don't think the bullet construction will allow that.

You can see from the tract that the SST dipped just a few inches before coming to a stop, so 99% of it's penetration was nose on. .

Dipped or rotated? I'd say much more likely the latter as what would cause each bullet to turn in its final inch of travel? I've studied the paths, cut open the gel and though it is hard to read the abrasions in the track I believe the bullets start to tumble after expansion.

 

[Boomer]

Would you like to see a Trophy Bonded Bear Claw taken from the same media? Every make of bullet that expands is turned to a big mushroom. The Perma Gel is a tough ride for a bullet, much tougher than an animal with no bone hit.
I have a big shipment of Barnes and Nosler E-tip coming, I've got 70" worth of gel set up so I will trap the bullets this time. My thoughts are the long for weight bullets won't do it. The bullets need to expand to a short shanked mushroom profile and I don't think the bullet construction will allow that.



Dipped or rotated? I'd say much more likely the latter as what would cause each bullet to turn in its final inch of travel? I've studied the paths, cut open the gel and though it is hard to read the abrasions in the track I believe the bullets start to tumble after expansion.

You can think what you like, but the bullet did not tumble because the wound tract is straight and a tumbling bullet will follow an erratic path. One of the reasons it did not tumble is because of the rotational velocity of the bullet that keeps it stable. By the time that the bullet looses enough momentum to continue to penetrate, the rotational velocity has also nearly finished and the bullet is now unstable.

I'm on my way out the door, but I'm sure this will continue.