.45-70 vs. .45-90 pressure/velocity advantage

[GEOMETRIC]

I am just getting acquainted with this web site so please excuse me if this question has already been posted. I know you can research it somewhere on here but I haven't found out how yet.
I have a Pedersoli (Trail Guns Armory) Kodiak Mk. IV in .45-70. I believe the maximum service pressure according to Pedersoli is about 28,000 psi. The gun will probably handle more than that but I have never been one to press the envelope. I feel much better when I know my equipment is well within it's design limits. I see loads from Lyman & Hodgdon pushing 400 & 420 gr. CB's at 1875, 1934, & 1845 fps. @ less than 2800 CUP. Yes, I know PSI is not the same as CUP but Lyman states they are very close in a .45-70. Push the velocity up 100 fps. & pressure jumps on the order of about 10,000 or more PSI. Now, I have no desire to make a .458 out of my .45-70 but there are times when the higher end loads could be useful. A Cape Buffalo hunt is pie in the sky for me but if you think a 400 lb. boar with 4+ inch tusks can't hurt you, you better think again! He can kill you with his dying breath.
That brings me to my question which is two fold. First, do you really get enough out of that extra 100 fps to justify the cost in pressure, recoil & wear & tear on you & the equipment? The other part of the question has to do with the fact that I have read discussions on rechambering .45-70s to .45-90. I have actually seen a Kodiak Mk IV advertised that was so altered. Could that increase in powder volume give you more velocity for the same or nearly the same pressure?
Actually, I am more worried about recoil. The gun will shoot loose long before it blows up but more recoil than it can handle will destroy it. A lower chamber pressure is indicative of a more gradual increase in velocity. The rate of energy transfer is a key element in any engineering or physics formula describing destructive forces.
There is new research on the effectiveness of .45 cal. bullets at various velocities but I could only find one guy that wrote that he used a double rifle in Africa in .45-70. His experience spanned a number of years & he reports good results. Other than he used .500 gr. bullets, I don't believe he said what the load was. Research in recent years shows that penetration starts to decrease over a certain velocity, as I imagine most of you already know.
BTW, I also have a Kodiak Mk. VI in .58 cal. Both are regulated far better than I expected. I thought I was going to have to do a lot of load development to get decent groups but both rifles produced great groups at any range that they should be used. The .58 shoots RB's as well as it shoots conicals. I usually use RB's for deer as that is more than adequate for any deer under 100 yds. I have a custom mold that produces a 420 gr.+/- bullet (.45-70) that I had made for a Ruger No. 1 but it works fine in the Pedersoli as well.

[bob208]

loading black powder the .45-90 has more then the .45-70. but with smokeless the .45-70is just as good.

[Chill Wills]

I agree. If you are shooting smokeless, which I see you intend to do, there is no reason to go to the effort of rechambering the rifle barrels. You would be splitting hairs for little gain.
If you feel you need more gun, you can get a larger gun, like a 12 gauge. Or hunt with a body guard with a 12 gauge.

On the other hand, well placed shots trump powerful but poorly placed ones. Being good with a gun counts. I am willing to bet a 20-1 lead-tin Lyman 457-193 bullet driven by BP to 1350fps will shoot through a boar from any angle except end to end. Your proposed 45-70 load is a heck of a lot more potent than that. And, it is the boar's front end that will be getting with the second barrel.

Hunting things that can hurt you is exciting, right?

Cool rifle! Have fun! Be safe!

[Edward]

No need to go 45-90 unless that gun weights enough that you start looking for the trailer hitch, I used to kill some big pigs with a custom Bighorn take down (65lbs stikbow),only got my cousin treed once but he was a scaredy kat

[NSB]

I'm still waiting to recover my first bullet from any of my 45-70s. I've shot deer from every angle and each and every time my 405g bullet traveling at a leisurely 1250-1450fps just goes in one side and out the other. There are guys on here and other sites who shoot hundreds of hogs with 45cal handguns with good effect. You've got to shoot a few critters with the 45-70 to really appreciate how good a cartridge it really is. Even a big hog is no match for it.

[GEOMETRIC]

NSB,
I am not a real avid hog hunter or deer hunter either. Some of these young guys think they need to kill 20 deer a year. When my freezer is full, assuming I find the time to fill it, I either stop hunting deer or start trophy hunting. A big trophy boar is usually so rank it will run you out the kitchen if you try to cook it. If you want meat, pick a nice fat pig around 100 to 150 lbs. Most places just want you to kill the hogs. I never liked just shooting anything just to leave it in the woods. You can catch a 1st. or second generation wild piglet with your lap dog. They eat real good though. Like I said before, I have never got any hog I have killed on a scale but I have killed a few that two grown healthy men could barely drag on the ground. I would guess their weight at between 400 & 500 lbs.. Remember, a wild hog has much less fat on him than a domesticated hog.
Thank everybody for your opinions. Actually, what you told me is pretty much what I was thinking. I wanted other peoples opinions to see if I am assessing the situation correctly. Any decent deer rifle will kill any hog. However, they generally don't kill big hogs in their tracks. That is fine as long as bad boy is in "flight" mode. If you made a half decent hit with anything reasonably adequate for the job, he usually dies soon after. The problem comes in when he decides to fight. Then you have to stop him before he hurts somebody, just killing him is not enough. A bad hog can do a lot of damage in seconds.
Some of these dedicated hog hunters kill & catch a lot more hogs in a year than I will ever see in a lifetime but I suspect they see very few really bad hogs. I was watching Mark Sullivan's video on handling a DG double rifle. He is not the most humble guy I ever saw but he knows what he is talking about. When somebody that talks about something I am interested in that knows his stuff, I listen. Mark is a well known white hunter/ guide that is famous for his cape buffalo & hippo safaris, if you don't know. I love his rifle. Mark says about 5 in 100 cape buffalo will charge. A wild hog is no Cape buffalo, obviously. They are not nearly as powerful or dangerous. Most run of the mill wild boars are not big enough to be a threat so your odds of even encountering a really bad hog are slim. I believe, of the really bad hogs, more than 5% will charge. That is based on my experience & the experience of people I know that do a lot of hog hunting. I have not killed a bunch of wild hogs, several dozen I would guess. Frankly, I prefer duck hunting or pheasant & sharptail grouse. Two of those hogs were really bruit boars. I shot the first one 7 times with a .32 Winchester. I knocked him down 3 times but each time he got back up. He was literally shot to pieces. When I opened him up, his internal organs ran out like water. Do you think I could have stopped him in 10 feet? Maybe if I hit him in the head with my .45-70. The second one I shot with a .45-70 with a 420 gr. bullet at about 1800 fps. out of a Ruger no.1. That's enough energy to take out any land animal on planet earth. The bullet went completely through the heart & lung area. He ran about 50 yards in heavy cover before expiring. I think I will try for a head or neck shot if I get another shot at a hog like that. He weighted less than half of what a big cape buffalo will weigh but how big do they have to be to hurt you? He easily weighted twice as much as most any man. Granted, your chances of encountering & being charged by a hog like that are remote.
Well, that is only part of the reason I was wondering if it was worth the effort to develop some more potent .45-70 loads. After hearing what you guys said & looking back at my own experiences, I am starting to believe what I really need to reliably anchor bad boy is not more power but better bullet placement. Body shots don't seem to produce instant kills. Yes, a .45-70 is a great cartridge. There is something inside of me that defies logic & keeps this hope alive that one day I will get to use it on something much bigger than a boar.

[NSB]

If I were to step it up, I'd probably be looking at a Barnes all copper bullet. I've shot a couple of things with these bullets and I was surprised at how well they actually perform. If I felt the need for a bit more power, it's certainly not difficult to get it out of the 45-70. I guess there's nothing wrong with "stepping it up" with a specific need in mind. Check out some Barnes bullets. I've used the Barnes Original which has a thicker jacket and is designed for very large game where penetration is desired. It ought to fit the bill for a large hog.

This is a Barnes .45 solid copper from a ML. Don't have an Original pic.