Muzzle Velocity vs Point of Impact Velocity

So this may be a dumb question but I have been looking around at various forums about 45-70 loads and how at some point the higher muzzle velocity translates into less penetration, specifically, it was stated that above 1650MV you see reduced penetration. It would seem to me that penetration would be more affected by the velocity at point of impact rather than muzzle velocity. Velocity can be calculated across the flight path of the projectile so if the MV is say 1900FPS but at 200 yards it is 1300FPS, wouldn't the penetration at 200yards be based upon the POI velocity and not the Muzzle Velocity?

It's all about impact velocity for performance on game when it comes to bullets in my opinion.
Every bullet will have a impact velocity range, in which it is supposed to do it's job as designed.
Some of those velocity spreads are narrow and others are broad.

My guess is that in the specialty pistol world for the majority (whatever that is), is that when hunting, the distances are not going to be far out there, so they may just work with MV and call it good. Simply a guess, on my last reason of why people are talking that way.

Point of impact velocity or terminal velocity (velocity at the termination of ballistic flight) are what determines bullet performance and are an important part about picking the right bullet for the right job.

Did the 45-70 discussion involve deformable vs hard cast lead?

I AM NOT BUYING "MORE VELOCITY = LESS PENETRATION", WHAT I DO SEE IS THAT WITH THE WRONG BULLET "BULLET INTEGRITY"/PENETRATION SUFFERS AT HIGHER MV's. BTW, CAST BULLETS, EVEN "HARD CAST", ARE AMONG THE BULLETS THAT CAN EXPERIENCE BULLET INTEGRITY FAILURE/LESS PENETRATION IF YOU PUSH THEM TOO FAST.

The discussion was mostly generalized from what I could gather and was specifically stating that for the 45-70, anything over ~1600FPS you would start to see less penetration from projectiles in the 400+gr. In other words, diminishing returns the higher the velocity. I understand that deformation of the bullet and other bullet "failures" would potentially cause penetration issues such as bullet path changes and deflection but I would think that at this point it would be more related to bullet construction/design than MV given the bullet is capable of achieving said velocities and you are not "over clocking" it as it were. I would agree with Ernie that given the relatively short distances of handgun hunting, MV is acceptable for calculation and that under say 100yards, look for a bullet that performs with in that limited velocity range. Thanks for the input folks. Very much appreciated. Looks like I have some tests to run

Hopefully no one will get upset or have their feelings hurt about what I'm going to say, but hopefully we all realize that we are grown ups too....the truth is, and the truth will always be...Velocity is your friend....it helps your bullets performance on game...it aids in tissue destruction and impact/knockdown and trauma that is caused from your bullet......the Linebaugh Theory is a LIE....a 45 Colt will not out penetrate a 460 S&W if you use the same bullets and shoot them into the same media...it was and is absurd to even think that nonsense was factual (aka a 45 Colt with a cast bullet at 1200 fps out penetrates a 458 Win Mag with a African Grand Slam Solid at much higher velocities) people once though that velocity made bullets explode like fairy dust...hence why it was a popular belief that expanding bullets traveling faster than 1100 - 1200 fps could not reach and destroy the vitals of game animals the size of boar or larger....I've always said that such beliefs were nonsense and the people that perpetuated these untruths were lying...that hurts people's feelings, but it is and was and always will be the truth. Big, Heavy bullets that are properly constructed, moving fast, will out penetrate big, slow moving bullets. Sorry if that goes against what some may try to sell you (and No, this isn't an innuendo), it's just the FACTS.......

"speed kills"....

There is a lot of velocity dropped in the first 100 yards that can really affect expanding bullets.
WRT shooting distances and Ernie, remember he smacks prairie dogs with open sights well past 100 yards

What he said.

Let's be mindful of that it was only one time...

Thank you all for your input. I learn a lot while reading the various topics on this forum. I for one appreciate your honesty and candor on these topics. I am one that has always tried to learn from my mistake but if someone is kind enough to correct me beforehand, so much the better.

We are all here to learn and share and conduct what some here like to call Science.
I'm a big proponent of doing the paperwork to figure out what you are thinking will actually work (figuring out expected MV, expected terminal velocities, bullet requirements for proper function) and then confirming the velocities. The next step which I haven't done much of (outside of hunting and google/YouTube reviews) but others here have done is bullet testing. Shooting water/gel/paper/animals/other at appropriate velocities (loading to lower velocity or shooting at expected distances) to confirm expected performance and then investigate performance at actual animals.

I've justified my lack of bullet testing by choosing expanding bullets that have terminal velocity requirements that are much lower then my expected hunting conditions. I've also found good testing results on various YouTube channels for the bullets at similar or lower velocities and then I've confirmed good bullet performance in hunting conditions.

Can you refer us to the relevant tests that you have performed which have helped you form your opinion?

Welcome.
Interesting two year old thread to pick up.
What handgun(s) do you like to hunt with?

That was in response to Franchise, I must have messed up the post. If somebody wants to say that other folks are straight lying when they refer to claimed to test results I like to find what they are basing their opinion on. It’s an old thread, but hasn’t the site been down for quite awhile?
Thanks for the welcome! It depends some on what is of interest at the time for me, .22s and a tc shorter barreled .45/.410 for turkeys and rabbits and wing shots on close quail, for big game 27-2, different iterations of 29s, and a Bowen 475. Plan to try my triple lock (44sp 7.5” target model) on javelina and maybe deer depending on if I can get good cast loads set up for it for next season. All iron sights, but may try to do a scoped freedom arms 2008 to practice shooting a scoped handgun. My eyes will likely demand it before too many years I think.

HD,
The way you show you are responding to s specific poster, Franchise in this case is to go and Click on the "Quote" tab on the bottom right of their post.
I did this to quote your last post.
I use some kind of optic with all of my hunting handguns.
What barrels do you have for the FA 2008?

Much appreciated! I think I just said reply under his post. I briefly tried a scope on a 29, I couldn’t hit with it and gave up quickly. It seemed so unsteady. I wrote it off to bad balance and figured why mess with trying to learn different techniques when I was happy with irons..That was a long time ago, I later learned it was possibly just magnifying the wobble that I was kind of coping with and not realizing it. I need to try again.
I don’t have the 2008 yet, I am very open to suggestions. I have missed a couple of great buys from guys who jumped in feet first and bought a couple of barrels and then got out of it, figured I would hold out a while and hope. I would like something that would be good for deer, was thinking 7mm-08 or 284 win, and something that would be good for jacks or squirrels.

I have seen mixed results with the FA 2008 single shot pistol in terms of accuracy. Some shoot awesome and others..meh
I sold mine. For the money, it was too inconsistent
A inexpensive entry level single-shot specialty pistol is:
https://www.gunbroker.com/item/921032197
https://www.gunbroker.com/item/921026184
https://www.gunbroker.com/item/921026185

6.5 Grendel, 6.5 Creed, and 243 Winchester are ones listed above.

If you want to get into a high quality rear grip specialty pistol, look at the Kauger Arms Black Widow. I love their action-So smooth!
https://shop.kaugerarms.com/products/black-widow.html
Just note they only list two cartridges, but the sky is the limit.
They can also do it as a single-shot to where you can use cartridges like the 284 Winchester, etc...
http://bulletin.accurateshooter.com...e-bishops-bolt-action-specialty-pistols/

CVA does Straight-Wall cartridges as well.
This lists both:
https://www.gunbroker.com/All/search?Keywords=CVA%20SCOUT%20V2%20PISTOL&Sort=13&PageSize=96

There some truth that more velocity can reduce penetratio.
Barns did a test with ballistics gel at 100 yards. One block was shot with a 30-06 and the other block with a 300 RUM, both shooting 180 grain TSX. They set chronograph behind the blocks to record exit velocity. The 300 RUM exited with 49 FPS, the 30-06 extra with 247 FPS. Obviously the 30-06 would have penetrated deeper. The wound channel from the 300 RUM was larger

Clair Reese wrote the twst from in an article

The next question then with that specific Barnes bullet is, does the amount of penetration in an actual animal, still enough for a exit with the RUM with that bullet at whatever impact velocity they chose?
What animal where they trying to equate if any?
Next, do you want a larger more traumatic wound combined with a greater hydrostatic shock, versus less shock and a smaller permanent wound channel?
When you begin to add in further distances to the mix, the RUM will end up having the same or similar expansion and trauma as the 06 does at shorter distances, with that specific bullet.
Since they are only looking at 100 yards, did they slow the speeds down to equate lower impact velocities for further distances?

I am betting, if they had compared solid bullets of the same type in those two rifles, the RUM would have greater penetration.

The information does not surprise me