those loads will work just fine. the 45-70 is one cartridge that has never needed any help in the killing department. the old black powder loads were a 400 to 500 grain soft lead bullet at maybe 1,300 or so and they would shoot through a buffalo with no problems. in my opinion there isn't any reason to load it much hotter than that and I have a Ruger #1S in 45-70

I believe it is the case head diameter that makes the difference. The backthrust is greater in a large diameter case as opposed to a small one. This is why you can get away with the high pressures of the 223 in a contender but the 308 won't work.
TC will chamber the 450 Marlin in the Encore(but not in a contender), so checking a new loading manual to compare pressures of the 450 to a 45/70 should give you the answer you are looking for.(the 450 marlin is only a hotrodded 45/70) Most of the custom makers will also chamber the 458 magnums by remington or winchester, including the large case diameter shortmags. this would lead me to believe that if the case heads are similar in diameter then similar pressures could be run without difficulty.
Rick

CRICKER: If you will measure you will find the head dia. of the 45/70 is roughly .505 inches and the 300 Win Mag is .512"
Now about the head diameter thing???????

So if a 45/70 is dangerous at 50000 psi then a 300 Mag at 63000 is out of this world right?

Here is a fact perhaps slighlty relative to this discussion.
Factory 300WSM (.555") loads operating in the 60K+ PSI range will shear locking bolts and cause the action to open upon firing.

DAVE JENKINS: Why would that be relevent to the discussion?

I could say that the Encore chambered for the 460 Weatherby and loaded to 60+ thousand psi could not only shear off the locking bolts but cause the gun to disinegrate. Well maybe not disinegrate but be unhealthy for the shooter and to bystanders.

Anyone could give an example of a load that could damage the gun. There have been bolt rifles damaged.

My questions remains that if a 300 Mag at 60+thousand psi is safe with a case head of .512" why wouldn't a 45/70 with a case head of .505" not be safe at 10+thousand less psi?

I know, I know, someone will bring up case strengh but like I said there are Federal cases one can use and they are strong. Also there are Starline cases and Remington cases which heavier loads are kinder to.

Lets not use the case issue on this ok.

BEARTRACK: Pressure is figured on the head area not the rim. The head of the 45/70 IS .505" not the rim diameter. For that to take place the pressure would have to be spread over the whole rim area not just the head.
There has NEVER been anyone that would believe rim diameter is the determining factor that has EVER studied hydralic pressure and how it is figured.
Before you argue with me on this ask someone that knows the way to figure psi over the area in which it is applied. Even if you would use your noodle you would see your theory is incorrect.
There is NO pressure pushing on the outsides of the rim except the pressure that is applied only by the casehead area times pressure.

CRICKER: As i asked how can a 300 Win Mag not be too much for the Encore and a 50000psi load in a 45/70 be too much?
I know there will be those that will cite case strengh as a point but we have pretty good cases in Federal and also Starline that is stronger than Winchester cases so lets leave the cases out of this.

Try the following link to get an explanation of how pressures effect the contender and encore. This article explains it much clearer than I can.
http://www.bellmtcs.com/FAQ/max_pressures.htm
After rereading this myself, I think that the lever action load levels probably create enough pressure for the encore.
Rick

guys,

I don't know why you think the case heads are that small? Check your reloading manuals, pick up one of your cases! The 45-70 is .608 across the rim! That is the portion that will be created the back thrust! For this reason the .532 (NOT .512) head of .300 Win is significantly smaller!

And its not about the diameter across the rim; its about area! There is also the friction created by the case, of which a .300 win will have slightly more, reducing further the back-thrust. If you loaded both to 60,000 PSI, w/o regard for the friction of the case, backthrust on the .300 would be 50,000 PSI (in round numbers) the .45-70 would be more than 57,000 PSI.

Use the hot Marlin loads (40,000 PSI) in the Encore and do not exceed!

BEARTRACK: You can believe all you want but what i say is right. The area of the casehead is.20030" times 50000 psi is1oo15 psi plain and simple. That is all that is pressing on the action in backthrust. The rim is part of the head but it is not the head only the body of the case that is part of the case body itself.
You are entitled to any belief you want this is a free country but if you put a fence post in the greoun on its end and put 500 pound on top all that is pressing against the ground is 500 pounds. If that same post had a board 3 feet in diameter is attached to the end of it and is resting on the ground and then put 500 pounds on top of the post all that is pressing on the ground is 500 pounds. The psi is less than the post area itself because the 500 pounds is spread over a larger area but it is still only 500 pounds. That is how hydralic pressure is increased or decreased in presses and so forth. By pressure pushing on smaller and larger areas from a given source or hydralic pressure.. Read up on it. THEN get back to me on it.

We use the outside mea. because it is easier to figure. One would have to section a case to get the case wall thickness etc. Then it would depend on the curvature of the wall as it meets the casehead too. It is all relevent in figureng just for the fun of it. Many other things come into play such as the area that the gasses have to expand in. When a .458 diameter bullet moves .100" inch it gives more space for the gases to expand in than a .308" dia. bullet does moving the same .100" so the pressure drop is more rapid than in a smaller bore .
Many things enter the picture not just casehead dia. but that is what many harp on in a religious manner. What about the 500 S&W in an Encore with a head diameter of .528" at 55000 psi? People are doing it.
So I guess the 45/70 should be loaded to around 10 thousand psi with a small charge of Bullseye to be safe and that may be pushing the Encore.
Do you think?

Me Plat,

I believe you are mistaken, not in what you said, but the issue at hand. We aren't talking about the preasure inside the case (PSI) as being the limiting factor on the T/C type actions. We are talking about the backthrust against the rear of the frame which has been notorious for causing the frames of Contenders to stretch, and will also do the same to the Encores, if backthrust is sufficient.

It isn't possible for that reward thrust to be limited to just the diameter of the case body at the base. If you mark the case head w/ marker (it shows up on my SS frame, perhaps whiteout on a blued frame) you can see that it will mark the full diameter of whatever the case head is. It doesn't just mark the part of the head that is the diameter of the body and leave the edges unmoved.

You may be right about the way Preasure is MEASURED, but you can't tell me the head of the case exceeding the body diameter is inert insofar as having no REWARD thrust. That would defy the laws of physics. That preasure is spread over the entire surface area pressing against the frame.

Morever, if what you suggest were true, then MFH and Plater and the many others who have checked in here would be correct. An Encore 45-70 would take the #1 loading because it would have less backthrust than .300 Win. BUT IT DOES NOT. NO ONE SHOULD USE RUGER #1 data in a Encore! (ephasis for those who would try).

Y'know, you can get a whole lot of opinions here, but the only way to know for sure is to call Thompson Center direct. Go to www.tcarms.com and either e-mail the question to them, or get their phone number and call.
Personally, I trust nobody but the manufacturer when it comes to questions of loading pressures.
Hope this helps

The Encore can take the same loads as the Ruger #1.

Talked with TC about this once. They will handle lever rifle loads. NOT Ruger #1's.

If you can buy an Encore barrel in .300 Win mag and many similar chambering that fall in the 'over 60,000 psi' range why would a max loaded 45-70 at significantly less pressure be a problem ?

Me Plat,

It isn't a matter of "believing." I want to understand this if I'm mistaken. So share you insight w/ me, because I'm not seeing it.

I don't know where you are comming up w/ your area figures, am I missing something? The area of a circle is pi x R squared. Even if your idea of the BODY, rather than the full case head being the only significant aspect in backthrust, at .505, the area of the .45-70 would be .629 sq.in.(round numbers)not.20030!

I certainly understand the illustration about your fencepost, but there are other factors when we are talking about the chamber and frame of a T/C. Primarily, it is that that the preasure is omni-directional, not down and we are talking about a completely enclosed object.

Until that bullet breaks away from the case and begins to move down the barrel that 50,000 PSI is pushing equally in all directions. The case exapands minimally in all directions, but the barrel is not the weak area of the T/Cs. No one bursts a barrel, nor is the web of the case going to blow out. It is the backward thrust of the case that is otherwise enclosed, including the rim, against the frame face that will cause the frame to stretch.

Let's go back to your post. Your are correct, that it is still just 500 lbs, but to liken it to an exclosed case, it would have to be 500 lbs pressing equally not just on the post, but on the 3 foot circle because the rim is prevented from bending held stiffly in place by the recesses cut into the chamber.

Now let's shrink this down. If we are dealing w/ 50,000 or 500 PSI, its just that pounds - per - square - inch. What happens if you have less than a square inch? The actual thrust momentumn against the frame is reduced by the decimal figure less that 1.0 square inches. AND, this is against the entire mass of the frame, not just the portion that the case head is in contact with.

This is why the contender, weak though the frame is, handles the .223 size cases, in excess of 50,000 PSI w/ ease! Yet, you will notice that no one chambers .30-06, .300 Mag, etc., in these. Equal preasure measureable in the case doesn't mean equal backthrust against the frame. That 50,000 Pounds per square inch has been reduced by what ever fractional part the area of the head of a .223 case is bellow 1.0 Sq. In.

The Ruger #1 can handle almost anything by virtue of its design (falling block) and its size. The Encore cannot! It will handle a lot, but highpreasure rounds w/ large heads and/or very short cases ( WSMs - reduced friction in the chamber, and therefore increase the backthrust)WILL WITH CERTAINTY stretch the frame of the encore and eventually ruin a fine handgun.

BEARTRACK: Just because you want to make something difficult out of something easy is your fault not mine.
The formula for area of a circle is Radius Squared times 3.1416 equals area. The radius of .505 is .2525 now if we take that we get .2525 times .2525 times 3.1416 we get .200296 or .20030. Machinist and others use the formula diameter squared times .7854 equal area. Before you argue that it is in the machinist handbook ok.
I know pressure pushes in all directions not just forward and backward. But, it is the pressure that is exerting backward that we are concerned with in this deal not anything else.
If we take .20030 times 50000 psi we get 10015 psi of pressure on the casehead.Now if we take a 300 Win Mag operating at 64000 psi we get .512 times .512 times .7854 equals .20589 si times 64000 equals 13177 psi on the casehead.
What is so difficult about that?
Just for your edification it would take a circle 1.1284 in diameter to make an area of 1 square inch.
In understanding pressures and areas we need to understand how they are figured and how that pressure is applied.
When we start to argue on something like this it is fruitless because I will never convince you of what I am saying.
Its like these idiots wanting to know how to figure energy and then arguing with the person trying to tell them. If they know enough to argue than they sure don't need to be asking question if they are so smart.
Now what a #1 can be loaded to and what is prudent is one thing. I know they can and have been loaded to unbelieveable pressure but we are not talking about that. We are talking prudent pressures not some unearthly pressure that some idiot had loaded to. Hornady and Barnes go up to 50000 cup which is enough. i know there are othere that have loaded then to that and way beyound but I have never stated that an Encore can handle these idiotic pressures.

MY QUESTION WAS IF THE ENCORE CAN CHAMBER THE 300 WIN MAG AND THE 375 H&H WHY CAN'T IT TAKE THE 45/70 LOADED TO 50000 CUP?
WITH LEAVING THE CASE CONSTRUCTION OUT OF IT. WE HAVE BETTER BRASS THAN IN THE YEARS GONE BY.

SSK Industries chambers .458 mag and a 50-70 pushing a 600 grain bullet 1600 fps...........HUMMMMMMMMMMMMMMMMM!

http://www.sskindustries.com/encore.htm

The operating pressure of the 458 is 630000 psi and the 300 Win Mag 64000 psi basically the same.

Adding to my post above, the .458 Win. is just a longer .45/70 with a belt instead of a rim. The brass is somewhat thicker in the .458 and does have some bearing on how much force goes back to the breechface, but the difference is probably very slight.

Again, go back to "hard opening," meaning hard to unlock as opposed to hard to extract, as a final test. If you find yourself in that position, back off for sure!

Mike