Velocity vs. KE in rifle rounds, terminally speaking...

[Unobtanium]

When comparing terminal performance of two rifle rounds in the same caliber (lets use 50gr TSX, and 70gr TSX), does velocity trump KE?

I understand that above "about 1800-2000fps" TSC is a mechanism of injury and tissue damage.

The 70gr and 50gr TSX loaded to 5.56 pressure will have similar KE out to about 50ish yards or so. However, their velocities are much more radically different.

Both will penetrate through/through on an unobstructed shot at a badguy, I would think, based on gel and on-game performance in the field.

Both expand to similar diameters (around 0.45-0.5").

However, the 50gr loading is traveling much faster.

Does this velocity translate into on-target performance, or after you hit that "magical" 1800-2000fps barrier, is it "pretty much all the same"?

Also one asks...would the 70gr TSX perform better, conversely, as it sheds less energy passing through the target, thus maintaining more/higher velocity "over-all" during its trek through said target?

I realize this is a more academic question, but it's one I've been curious about ever since talking to a friend of mine who shoots hundreds of hogs per year. His experience is that 70gr TSX loads drop hogs harder than the conventional bonded bullets, the 70gr drops them harder than the 62, and so on. I figure after shooting hundreds of animals, trends DO emerge. I am wondering...why? What's the science or mechanism behind it? Is the higher penetration (and thus implied velocity-through-target) of the TSX the reason? Something else? What makes a 70gr TSX that expands to .50" so much more effective than a 64gr Gold Dot that expands to 0.50" when both pass through the target?

[DocGKR]

In the example above, the 50 gr TSX tends to stay in human torso targets while the 70 gr TSX is more likely to exit in those circumstances. For punching through both shoulders of a hog or taking a long range shot in combat, the 70 gr TSX is the way to go. For LE or defensive use in urban and suburban environments, the BH 50 gr TSX offers optimal penetration characteristics. I'd happily use either one without any hesitation if I was given an unlimited free supply...

"What makes a 70gr TSX that expands to .50" so much more effective than a 64gr Gold Dot that expands to 0.50" when both pass through the target?"

I can't say this is true in actual shooting incidents involving humans; although if we presume it is an accurate statement, we could perhaps hypothesize that it is related to the sharper cutting edge of the TSX.

[Unobtanium]

In the example above, the 50 gr TSX tends to stay in human torso targets while the 70 gr TSX is more likely to exit in those circumstances. For punching through both shoulders of a hog or taking a long range shot in combat, the 70 gr TSX is the way to go. For LE or defensive use in urban and suburban environments, the BH 50 gr TSX offers optimal penetration characteristics. I'd happily use either one without any hesitation if I was given an unlimited free supply...



I can't say this is true in actual shooting incidents involving humans; although if we presume it is an accurate statement, we could perhaps hypothesize that it is related to the sharper cutting edge of the TSX.

Thanks! The latter was true of a deer my friend shot with gold dot 64gr that I sent him. 18" penetration and about .5" expansion. He said it worked well but the tsx 70gr always caused more dramatic reaction from the animal and resulted in quicker drop.

I hypothesized it was the relatively flat meplat of an expanded tsx vs. The more dome shape of the jsp? Also....tsx petals don't feel or look sharp to me. Is it the velocity that "makes them ssharp as they pass through target? Also, the t series doesn't seem any more effective than other rounds. I know that's a handgun round, but regarding sharp petals and all.

How are the 55gr hornady gmx in ois? Are they exiting?

[Chuck Haggard]

One thing the 70gr will do with that extra penetration is hit more tissue on shots that aren't just broadside.

The 70gr would be more likely to do something like penetrate through the entire animal and hit a large bone on the far side, say a frontal quartering shot that hit the hip or leg on the way out, where the lighter bullet wouldn't do so. I would expect a more noticeable effect on the animal from such a shot.

[DocGKR]

Yes indeed.

[Rich]

In the example above, the 50 gr TSX tends to stay in human torso targets while the 70 gr TSX is more likely to exit in those circumstances. For punching through both shoulders of a hog or taking a long range shot in combat, the 70 gr TSX is the way to go. For LE or defensive use in urban and suburban environments, the BH 50 gr TSX offers optimal penetration characteristics. I'd happily use either one without any hesitation if I was given an unlimited free supply...



I can't say this is true in actual shooting incidents involving humans; although if we presume it is an accurate statement, we could perhaps hypothesize that it is related to the sharper cutting edge of the TSX.

I know of a hunter / guide over another forum who has shot 1000 of deer / hogs he swears the TSX does more damage compared to the Gold Dot /TTBC. According to him he has tested all the popular expanding loads in 223/5.56
BTW I think he favors the 70gr TSX. I think you may know who I'm talking about.

[DocGKR]

That is why TSX/TTSX are some of my favorite hunting loads, but they don't do quite as well against barriers as bonded loads.

[Unobtanium]

That is why TSX/TTSX are some of my favorite hunting loads, but they don't do quite as well against barriers as bonded loads.

Just a hypothetical question...but...not really, depending on what your job is, as sadly, many of our LE are faced with exactly this situation.

If someone told you "Dr, today, someone is going to try to kill you. I don't know where, I don't know when, but I, the genie of hypothetical situations, can guarantee that you will get a shot or two off from your M4. It may be in a traffic jam at 2pm, it may be in your home at 1 am, it may be in a parkinglot, but for today, you may carry your M4 everywhere you go." What would be in your magazine?

[Jeep]

Now that is a very interesting question. In other words, what round is the best compromise when you don't know which tactical situation you will face?

[Unobtanium]

Now that is a very interesting question. In other words, what round is the best compromise when you don't know which tactical situation you will face?

It's what civilians who travel, and police who do their jobs, face, every day. I am curious what the good Dr's "best compromise" would be.