Velocity vs Energy

[FEENIX]

Yup Feenix, your're good - my point was there is a big difference between velocity, and velocity squared. The electrical engineer in me gets bent out of shape on such matters. An engineer would say energy is relative to velocity, and proportional to the square of velocity.

The nice thing about energy is it has no direction. It is just a quantity! (Now I'm just playing with words, but that's what forums are for, right?)

Momentum on the other hand has a direction. Let's take a look at the momentum in the OP's example;

180gr @2057fps = 7.31 Ns

Vs

250gr @1810fps = 8.9 Ns

The units are Newton-Seconds. I recently read Issac Newton is the first individual credited with strapping a telescope to artillery - the first telescopic sight, in the 1700's! Let's give the guy some credit; yay Newton, so glad that apple fell on your head!

So even though the energy is pretty close - as Feenix showed, about 10% in favor of the 338. 338 has about 20% more momentum than the 7mm (with these imaginary bullets, at this imaginary distance). This suggests that not only will the 338 make a bigger hole, but it's likely to penetrate deeper also.

No need to trust the math, because people who have used both (and some here have) are telling us that!

I value personal experience more highly than math, which can be misleading (ahem, energy).

If you read my responses, I never disputed any of your claim, magnitude of the differences, or math, but simply the directional relationship as noted in my original post in #22 and as defined in #38. I agree, there is no substitute for real world experience.

Excellent discussion.

Cheers!

 

[djm670]

Yup Feenix, your're good - my point was there is a big difference between velocity, and velocity squared. The electrical engineer in me gets bent out of shape on such matters. An engineer would say energy is relative to velocity, and proportional to the square of velocity.

The nice thing about energy is it has no direction. It is just a quantity! (Now I'm just playing with words, but that's what forums are for, right?)

Momentum on the other hand has a direction. Let's take a look at the momentum in the OP's example;

180gr @2057fps = 7.31 Ns

Vs

250gr @1810fps = 8.9 Ns

The units are Newton-Seconds. I recently read Issac Newton is the first individual credited with strapping a telescope to artillery - the first telescopic sight, in the 1700's! Let's give the guy some credit; yay Newton, so glad that apple fell on your head!

So even though the energy is pretty close - as Feenix showed, about 10% in favor of the 338. 338 has about 20% more momentum than the 7mm (with these imaginary bullets, at this imaginary distance). This suggests that not only will the 338 make a bigger hole, but it's likely to penetrate deeper also.

No need to trust the math, because people who have used both (and some here have) are telling us that!

I value personal experience more highly than math, which can be misleading (ahem, energy).

 

[djm670]

Ha ha.. the only issue is the is equal and opposite action... the 338 is kicking your shoulder harder. I would opt for the 6.5 be it a Creedmoor, 6.5-284 Nosler or a .264 Win Mag.... I had you figured for a refrigeration engineer based on the icon chart.

 

[Hand Skills]

Ahh, that's a pretty good guess! This is indeed a pressure temperature chart, but it's for atmosphere. Density Altitude was developed for aviation. It combines barometric pressure, temperature and altitude into one number... which happens to be handy for long range shooters as well.

 

[djm670]

Ahh, that's a pretty good guess! This is indeed a pressure temperature chart, but it's for atmosphere. Density Altitude was developed for aviation. It combines barometric pressure, temperature and altitude into one number... which happens to be handy for long range shooters as well.

View attachment 103461

Aviators, Long Range Shooters and Old Time Drag Racers..... Yeppers, thought it was a psychrometric chart at first as it was too small to read.. now that it is inlarged I recognize it for what it is....

 

[Gregger]

If you show up with a 45/70 to hunt dangerous game in Africa you're probably going to get laughed out of camp.

It simply doesn't have the energy to compete with the African magnums or even the .375 Ruger which gives you 150-200fps more velocity than the .375 H&H.

It's big, it's slow and it's fine for everything we have but not for African dangerous game.

Ever heard of Vince Lupo? He took all of the African big 6 with a Marlin lever action 45-70 loaded with Garrett Hamerhead bullets. 400+gr hardcast lead bullets with a "Big" meplat have penetrated both shoulders of a Cape Buffalo and killed a cow that was standing behind him, this was done by Brian Pearce and documented in Rifle magazine 2004.

 

[djm670]

Ever heard of Vince Lupo? He took all of the African big 6 with a Marlin lever action 45-70 loaded with Garrett Hamerhead bullets. 400+gr hardcast lead bullets with a "Big" meplat have penetrated both shoulders of a Cape Buffalo and killed a cow that was standing behind him, this was done by Brian Pearce and documented in Rifle magazine 2004.

Very interesting reading.

http://www.garrettcartridges.com/luposafaris.html

"On this, and my next two safaris, I took as my primary rifle, a lever action 45-70 Marlin rifle and a fair supply of Garrett Hammerhead Cartridges in 540 grain and 420 grain loads. I had used this rifle and ammunition combination with great success on many other North American hunts and felt confident that this combination could take on whatever Africa had in store for me. One of the first things you do after settling in (unpacking etc.) is to immediately go to a firing range and check that your rifle has not be en so mishandled as to warrant it useless! I honestly believe I heard gasps as I took my 45-70-lever action Marlin out of its case. The P.H.'s on this side of the "pond" used primarily double rifles and huge magnum bolt rifles. Too compound the matter, I loaded the rifle with the most unusual cartridges that they had seen, 540 grain, solid cast, Garrett Cartridge Hammerheads. After punching out the center spot 3 times at 100 yards and their examining both the cartridge and the decimated backstop, they concluded that it would do "splendidly". "

"I am looking down the barrel at a huge male Leopard running straight at me full steam. Despite my best efforts the "only" shot I could get off was when the Leopard was 6 inches "in front" of the muzzle. The 420gr Hammerhead hit him square in the left eye killing him instantly. Needless to say, after we got out of shock, it was high fives and cheers all round! Believe me, that 220lb-charging Leopard took a bunch of years off of my life,"

 

[Greyfox]

No thanks on the 45-70. For African dangerous game at spitting distance I'll stick with my 500-450 H&H Double with 480gr Woodleighs at 5000FPE, Taylor KO: 67.5.

 

[djm670]

No thanks on the 45-70. For African dangerous game at spitting distance I'll stick with my 500-450 H&H Double with 480gr Woodleighs at 5000FPE, Taylor KO: 67.5.

I hear you! But these stories are amazing.

"He was in deed a huge boss bull Hippo, standing alone facing me about 15 feet from the lakes edge, munching head down on some tender grasses. BUT he was also only about 15 feet in front of me!
The PH slowly slid up alongside of me and tapped his finger to the bridge of his nose between his eyes several times. There was no doubt about what he wanted me to do. Nail the big bull between the eyes as his head was down and his attention was on eating. I eased the hammer back from half cock to the full back position and gently squeezed the trigger when the crosshairs of my scope held firmly on a spot between the Hippo's eyes. CLICK! The loudest click I had ever heard in my life sent waves of shivers down my spine. My mind went into "overdrive" trying to analyze what had happened. The stunned look on my PH's face must have mirrored my own as I saw his huge double rifle begin to move up towards his shoulder. But my mind had already told me that I had NOT pushed off the cross bolt safety and the hammer had slammed home on the safety bar. My fingers had already pulled the hammer back and released the safety button and had realigned the rifle so that I now again could take up my sight picture. Only this time the bull was looking straight at me and appeared to be coiling to spring forward into a full charge. But my had already left the barrel hitting the Hippo perfectly between the eyes and dropping him in his own footprints. He no sooner hit the ground than I slammed another 540gr Hammerhead bullet two inches to the left and two inches above the first bullets impact hole. The whole chilling event seemed like hours to me but in reality took seconds."

 

[Lonewolf74]

I'd hunt anything that walks this earth with my Marlin 45-70 long as it's my handloads I'm packing.

 

[Gregger]

I'd hunt anything that walks this earth with my Marlin 45-70 long as it's my handloads I'm packing.

Same here, its an absolute hammer when loaded heavy

 

[djm670]

Same here, its an absolute hammer when loaded heavy

You guys are impressive... I hurt after about 5 rounds of 300/305 grain factory ammo with my stock 1886 Winchester .45-70 at the range. I can only imagine what it would feel like with your hand loads or those Garrett 540 hard cast plus P's.

 

[Gregger]

The heavies hurt on both ends, the factory stuff is loaded mild for the old trap door guns. Load a 400 or 500gr bullet to max pressure and it will kill your shoulder. My deer load is hornady 300gr hollow point at 1700fps always get pass throughs.

 

[FEENIX]

You guys are impressive... I hurt after about 5 rounds of 300/305 grain factory ammo with my stock 1886 Winchester .45-70 at the range. I can only imagine what it would feel like with your hand loads or those Garrett 540 hard cast plus P's.

I was out at the range this AM and an old timer (76) next to me was shooting a Taylor's Rolling Block in .45-70 with 30" barrel. I do not remember the slugs but at least a 500 grainer and he was grouping them at .5-75 MOA at 200 yards with open sight.