O.K. Pressure in the Modern Marlin Rifle?

[jaycocreek]

Someone explain to me what is the maximum pressure for the Modern 45-70.And then explain the two new one's(.480 and .475) with 48 and 55,000 PSI repectivly out of the same action.I honestly am curious how this can be.I am not trying to start trouble.It is an honest question that many wonder about.
I do know the 45-70 SAAMI Spec's and the .450 Marlin and who came up with 40,000 CUP for the Modern 45-70.

Inquisitive mind's want to know.Jayco.

[dla]

Well I suspect that you can hit the necessary RC hardness with heat treating. But why should Marlin spend the money to heat treat stuff for 28K PSI SAAMI 45-70?

So you can take the chance that Marlin is uniformly heat treating ALL their barrels and receivers to handle the high pressure cartridges, but Marlin is under no obligation to do so.

Maybe you should get maimed by a exploding rifle and then try to sue Marlin. I'm not sure how well you will fare given that Marlin has always stated that the 1895 45-70 is for SAAMI-spec ammunition.

[jaycocreek]

Good responce DLA.But the fact is if you reload your not covered under any of there rounds.I guess people like Buffalo Bore and Real Gun's are not up to date.Both load over 40,000 CUP.

I guess we will never know.Jayco.

[jaycocreek]

I guess the short answer is that there are those who are taking the 45-70 somewhat over 40,000 CUP. Tim Sundles of Buffalo Bore has stated that some of his 45-70 Lever Gun Mag. ammo is loaded to the high 43,000s. Joe at Real Guns has said his are under 45,000 psi. In your search it sounds like you have entered the realm of the experimenter. You can have loads pressure tested by several labs. May be the way to go in your ultimate search for this load.

The Hodgdon #27 45-70 350 grain maximum load using H4198 and adapted to the 350 grain Hornady FN achieves around 2150 fps in a 22" barrel and about 2080 fps in an 18.5" barrel. Of course, each gun is an individual and some will be fast, taking a maximum load, while others cannot approach the same.

Out of respect,There are know names to that one.But a very respected person on Marlin Talk.

[jaycocreek]

Ed-Break the ice?Check out my sign up date.

Do I have to call you Mr.Now that your a moderater?I hope not because it would be Mister Ed I know your young but that isn't good,it was a T.V. show.

Best of luck.Jayco.

[jaycocreek]

Alzeimer's M.S who know's what I remember? :lol:  :lol: Just kidding.Next time I will post a good one.Just had to say Howdy my way.Sorry to the rest on here.Jayco.



Did I do that?

[Coyote Hunter]

Well, this isn't Marlin Talk, and Marlin is no longer our host, so I guess we can vent freely.

One of my personal pet peeves with Marlin was the fact that they were so cagey with the pressure specs for the 1895's.  I think their actions in this area did a disservice to their customers and to their own reputation.

There is no doubt that the 1895's will safely handle pressures well beyond SAAMI "Trapdoor" .45-70 levels of 28,000 CUP.  There is also no doubt that the 1895M/MR (450) will safely handle SAAMI pressures of 42,500 PSI (or 43,500 PSI or whatever it is).

So the question becomes, "What is the difference between the 1895 .45-70's and the 1895 450's?"

Marlin has stated there are two primary differences - barrel thread and heat-treatment.  There is no question that the threads are different, but the "different" heat-treatment remains a mystery.  Let me deal with each of these separately.

First, the barrel threads.  Marlin contends the 450's threads are stronger.  (Yawn!)  The question is, are the threads on the .45-70's strong enough?  Based on various tests that have been performed by companies providing 40,000 CUP load data, and the fact that we don't have 1895's blowing up all over the place, the answer is obviously "Yes".  My personal feeling is that the thread change was done primarlily for manufacturing reasons -- to positively prevent a rifle leaving the factory with a 450 receiver and a barrel chambered for .45-70 , or vice versa.

Heat treatment.  Marlin's contention that the 450's are heat-treated "differently: is undoubtedly true -- the question is "What is the difference and does it materially affect receiver strength?"  My guess, after talking to Marlin and getting non-responsive and guarded answers, is that "different" means little or nothing more than "separate" in this case.  From a manufacturing perspective, this makes great sense -- heat-treating 450 and .45-70 receivers together would add an extra step of sorting them out afterwards.

Then there are other factors to consider.  Various sources of load data provide 40,000 CUP data for the .45-70, and Marlin is well aware of this.  If in fact that data was unsafe, Marlin's lawyers would be in the courts seeking cease and desist orders, as failure to do this would reasonably be viewed as tacit complicity.

And don't forget the .444 Marlin, which is built on the same basic receiver as the 1895 .45-70's.  Hodgdon provides load data for the .444 that reaches 42,500 CUP.  Is the .444 unsafe at those pressures because it lacks the 450's barrel threads or heat treatment?  Nah...

[dla]

Using modern materials, Marlin probably has lots of safety margin built into the 1895 design when operating at the 28K PSI SAAMI spec. And given the yield strength of brass, I don't think bolt thrust is the main issue at all. The main failure point is the first 2 inches of barrel.

Like all the "remove the unwanted material" manufacturers, Marlin starts with relatively soft metal, performs all their machining, and then does some level of heat treatment. But heat treatment is tricky as things warp a little and it is difficult to straighten after treatment.

Now I'm not a mechanical engineer in real life, nor do I play one on TV. So I don't know the difference in difficulty in treating a mass-produced barrel from 28RC to say 50RC. I know that custom barrel manufacturers  spend a lot of time at it. I doubt Marlin spends as much time on all the parts of an 1895 as Kart does on a single barrel (judging by some of the shoddy work Marlin does from time to time). What I do know is that to safely handle, with good safety margin, a 55Kpsi cartridge, you need a properly heat treated barrel and receiver in the 1895.

My point is that Marlin can have shoddy heat treatment for 45-70 barrells and receivers and be OK. If you think that you're safe pushing the 45-70 to 40Kpsi, you're on your own. Marlin, given their spotty quality, probably ships untreated receivers and barrells from time to time. In fact, given the low SAAMI 28Kpsi operating spec, Marlin may not do anything more than some case hardening for scratch resistance.

I doubt that Marlin does the old "blue pill" final test process, like Winchester did on the pre-64 M70. And I don't see any QC stamps where somebody did a quicky hardness test like on a Mauser. I could be very wrong, Marlin may do all of this and more, but from owning a couple of Marlins I'm a bit skeptical.

[jaycocreek]

Your loads should be just fine and certainly within the operating limits of your rifleYou may be running slightly higher pressures than our test data due to the use of the nickel plated brass and factory crimp. Nickel plating of brass does decrease the capacity of the brass by a tiny fraction and the factory crimp does a better job of retaining the bullet than a standard roll crimp. The increase in pressure over our results would be minor.
---------------------------------------------------------------------------------
That responce by Hodgdon on Mac's load made me wonder what they think the Maximum operating pressure for the 45-70 is.His  of course was a Nosler and H-4198 with a 2288 fps average in the Guide Gun.The wording,certainly within the operating limit's of your rifle makes me wonder just exactly what is the operating limit's of your rifle.

I guess we may never know and for the Guide Gun I look at 1900-2100-2300 being the three top loads being 400-350 and 300 grain bullet's.My goal is to get about 2100 fps out of a premium 350 grain bullet in the Guide Gun safely as Buffalo Bore has done atleast in the ones I have but I suspect this lot might be a hair over 40,000 as with Real Gun's data pushing atleast one 400 grain over 2,000 fps in the Guide Gun.

Best of luck.Jayco.

[dla]

Jay: I think you're missing the main point here, so let me try one last time.

Marlin has no reason to spend the money to make the 45-70 1895-series "safe" at 40Kpsi.

If the 45-70 1895-series is safe at 40Kpsi today, there is no guarantee that it will be safe tommorrow.

Why am I harping on this? Two reasons:

(1) Everybody who believes that the Marlin 1895 in 45-70 is designed and manufactured to safely handle 40Kpsi is pissing in the wind. Marlin makes no such claim.

(2) There's no good reason to be running the 45-70 at that pressure in the first place. You of all people should know that you don't gain squat by pushing a cartridge to the hairy limits. If that cartridge/rifle combo kills everything in the lower 48 running at 21Kpsi (true trapdoor specs), why do you think things will be deader when pushing the envelope to 40Kpsi?

[jackfish]

Marlin has no reason to spend the money to make the 45-70 1895-series "safe" at 40Kpsi.

Then why do they do it?  Because since 1972 they always have.  What you are missing is that since the Marlin 1895 was reintroduced in 1972 it has been manufactured essentially the same way with essentially the same materials.  Over the intervening 32 years the shooting industry has determined that the Marlin 1895 45-70 is safe operating at a pressure of 40,000 CUP.  It is certainly safe under that pressure and recent experience suggests that it is safe at somewhat over that pressure.  Does it matter?  Probably not if one follows accepted reloading practices and published reloading data.

(1) Marlin also has not said that it does not in light of repeated claims by others that it can.  All they have ever said is that the warranty is void if any non-SAAMI, non-standard or reloaded ammo is used in their rifles.  You are pissing in the wind if you think that it can't.

(2) There is just as good a reason to run the 45-70 at 40,000 CUP in the Marlin 1895 than there is to run any other cartridge/rifle combination to an accepted maximum load.  Again, your personal preference does not count for squat.  It is just your preference, not mine.  It is probably shared by others, as is mine.  I would challenge you to prove that your preference has any more validity than mine.  You can try I guess, but you can't.

[dla]

Marlin has no reason to spend the money to make the 45-70 1895-series "safe" at 40Kpsi.

Then why do they do it?

They don't. Prove me wrong with design information from Marlin. I don't care that people routinely get lucky. Show me that Marlin had designed the 1895 to 40Kpsi.

[John Traveler]

What is the SAAMI pressure for .444 Marlin ammunition?

[dla]

What is the SAAMI pressure for .444 Marlin ammunition?

What is the time on Mars?

[John Traveler]

dla,

I wonder if you are even a shooter OR a reloader.

You already stated that you are not a mechanical engineer or play one on tv.  I believe it.

The question was what is the SAAMI max pressure for the .444 Marlin.

I looked it up. It's neat 44,000 cpu.

Now, does THAT answer your challenge of showing you where Marlin designs the M1895 for 40,000 cpu?

Marlin will not release its design parameters or manufacturing testing for their products.  Its a liability thing.  They simply adhere to established SAAMI standards.

John

[jaycocreek]

John-I don't know the SAAMI but Hodgdon loads up to 42,600 CUP on the internet.

DLA-The time on Mar's is a quarter past the hour.Now Venus -Saturn-Pluto-Neptune and Uranus are quite different,but that's another post.  :lol:

Best of luck.Jayco.

[jackfish]

Our friend dla,

The Marlin 1895 and 444 are based on the Marlin 336 action.  The steel used in both is identical.  The 444 Marlin has a SAAMI pressure specification of 44,000 CUP which was based solely on its chambering in the Marlin 444 in 1968.  The Marlin 1895 chambered in 45-70 Gov't was reintroduced in 1972.  This rifle was identical to the Marlin 444 except for slight modifications to accommodate the 45-70 Gov't cartridge.  Marlin is a member of SAAMI so of course will not support the use of their firearms with non-SAAMI ammunition.  The SAAMI pressure specification for the 45-70 Gov't is based on its chambering in older guns such as the Springfield Trapdoor series and other old single shot rifles and has nothing to do with the safe potential use of the 45-70 Gov't in the modern Marlin 1895, Ruger #1/3 or Siamese Mauser conversions.  The 444 Marlin has approximately 10 percent less cartridge head cross-sectional area interfacing the bolt face.  Hence, the 45-70 Gov't will exert approximately the same bolt thrust at 40,000 CUP as the 444 Marlin will at 44,000 CUP.  I don't need Marlin to tell me that the Marlin 1895 in 45-70 Gov't can safely operate at a maximum of 40,000 CUP.   The shooting industry has recognized that for at least 20 years.  Go ahead, imply that the leading lever gun expert in the country, M. L. McPherson, is pissing in the wind.  But I'm going to believe him over you anyday.  Who the hell are you anyways?

[John Traveler]

Jayco,

you crack me up!

The hot factory .444 Marlin pressures is exactly why handloaders started to hot-rod .45-70 in the Marlin M1895.  Exactly my point.  They've been doing it for some 30 years now apparently without any disasters.

John

[w30wcf]

Howdy,

In the current Hodgdon #27 manual,  there are three levels of .45-70 loads referenced.  Under the data "Intended for the 1895 Lever Action Marlin Only", they show some loads at 40,000 cup as maximum pressure. The test barrel length is 24".

300 gr.  60.0 / H4198 / 2,424 f.p.s. / 40,000 cup

350 gr.  54.0 / H4198 / 2,191 f.p.s. / 39,300 cup

400 gr.  50.5 / H4198 / 2,002 f.p.s. / 39,400 cup
400 gr.  55.0 / H322   / 1,984 f.p.s. / 39,200 cup  
400 gr.  58.0 / H335  /  1,995 f.p.s. / 40,000 cup


At the top level for strong single shot rifles, they show loads at 50,000 cup, but the velocity gain is minimal for the extra 10,000 cup.

300 gr.  2,532 f.p.s. / 50,000 cup
350 gr.  2,300 f.p.s. / 50,000 cup
400 gr.  2,108 f.p.s. / 49,100 cup


The .45-70 works just great at 40,000 cup!

w30wcf

[Mac11700]

And the other side of the coin...(just for grins here guys :lol:) is it works just fine at a-lot less pressure too....isn't  it a great cartridge...


Man now this place really feels like home. Seems just about right...now who's missing here from this one?

I'm  really glad to see you all here...


Mac

PS: Jackfish...thanks for the heads up on the links to the wildcat issue of mine.
Mac

[Coyote Hunter]

Jay: I think you're missing the main point here, so let me try one last time.

Marlin has no reason to spend the money to make the 45-70 1895-series "safe" at 40Kpsi.

If the 45-70 1895-series is safe at 40Kpsi today, there is no guarantee that it will be safe tomorrow.

Why am I harping on this? Two reasons:

(1) Everybody who believes that the Marlin 1895 in 45-70 is designed and manufactured to safely handle 40Kpsi is pissing in the wind. Marlin makes no such claim.

(2) There's no good reason to be running the 45-70 at that pressure in the first place. You of all people should know that you don't gain squat by pushing a cartridge to the hairy limits. If that cartridge/rifle combo kills everything in the lower 48 running at 21Kpsi (true trapdoor specs), why do you think things will be deader when pushing the envelope to 40Kpsi?

As it was so often on Marlin Talk, dla, your perspective is severely limited.

Contrary to your first but unnumbered point, Marlin has very good reasons "to make the 45-70 1895 series "safe" at 40Kpsi".  Amongst these is the fact that Marlin management is very aware that there is considerable amount of .45-70 40,000 CUP load data in circulation which is advertised as being specifically for the MARLIN 1895 rifles.  (To name a few:  Barnes, ".45-70 (1895 Marlin)", at 40,000 CUP; Hornady "45-70 Government (1895 Marlin)", at 40,000 CUP; and Hodgdon "45-70 Government (Lever Actions)*, "These data are intended for the 1895 Lever Action Marlin only", at 40,000 CUP.)  Then there are the smaller ammunition manufacturers who load beyond 28,000 CUP, again specifically mentioning Marlin 1895 rifles in their literature.  Knowing this and subsequently building a 1895 in which these loads were unsafe would open the Marlin company up to potentially ruinous lawsuits.  Its obvious that your legal credentials are about as valid as your mechanical engineer credentials.

To your numbered claims:

(1)  Rifles built on the 336 frame include chamberings in the following:
.30-30 (SAAMI 38,000 CUP)
.444 Marlin (SAAMI 44,000 CUP)
.35 Remington (SAAMI 35,000 CUP)
.356 Winchester (SAAMI 52,000 CUP)
.375 Winchester (SAAMI 52,000 CUP)
450 Marlin (42,500 or 43,500 PSI)

While Marlin makes no claim that the 1895 .45-70 is safe at 40,000 CUP pressures, they haven't sued other manufacturers to prevent them from publishing "unsafe" 40,000 CUP .45-70 load data or selling "unsafe" 40,000 CUP ammunition, either.  Never mind that Marlin has a vested interest in not endorsing the .45-70 as safe at 40,000 CUP -- an interest called the 450 Marlin, the sales of which would not be helped by such endorsements.

That said, it doesn't take all that much to handle 40,000 CUP pressures with modern steels.  Marlin would almost have to try to make the 1895 unsafe at 40,000 CUP.  The 1894's are rated for SAAMI 36,000 PSI ammunition (.44 Mag), and that design is not as strong as the 1895.  Heck, even the 9mm Luger is rated at 35,000 PSI, and the pocket pistols designed for this round have far less steel in them than the 1895.

Pissing in the wind?  Not hardly, and my head isn't buried in the sand, either.

(2)  "There's no good reason to be running the 45-70 at that pressure in the first place".
This was one of your favorite claims on Marlin Talk.  At one time you were adamant there was no reason to push past 1600fps.  Later your limit became 1700fps on cool days and 1800fps on hot days.  

Well, maybe there is no good reason for dla "to be running the 45-70 at that pressure ", but there is no reason for others not to if the pressure is safe - which decades of history, testing by various bullet and powder manufacturers and handloading experience would indicate is the case.  By all means, dla, feel free to ignore that body of evidence.

As for myself, running the Marlin at 40,000 CUP with my handloads turns it into a rifle I can hunt effectively with in the open sage country, as I demonstrated with clean, one-shot, kills on elk (213 yards) and deer (192 yards) last November.  For a fixed target size of 6", my 40,000 CUP handloads add 40 to 50 yards additional Point Blank Range.  That may not be important in the Oregon woods where you hunt, but when the nearest tree is a mile or two away it can make the difference between meat in the freezer or none.  And the extra range is cheap insurance when there isn't time to pull out the laser range finder.

[jaycocreek]

The right column shows how much the bolt thrust for the given load is over the bolt thrust for a 45-70 loaded to saami's limit.

For example, the bolt thrust for a 444 loaded to 42000psi is 41% greater than the bolt thrust of a 45-70 loaded to 28000psi.

On the same token, the bolt thrust for a 45-70 loaded to 40000(7359), is only 2% more than a 444 loaded to 42000(7287).


What that is supposed to mean is that assuming the actions are identical, and the only two factors that matter are chamber pressure and bolt thrust, then a max load of 39,600psi for a 45-70, would be equal to a 42000psi load for a 444.

[dla]

Coyote & Jack : just like old times here

Both of you are lost in space, one legally, the other mechanically.

Marlin has no obligation to violate their specifications in order to accomodate people who do stupid things. When you blow up a rifle, Marlin's defense will hold - they never told you, or encouraged you to hot-rod past 28Kpsi. They never release any information implying that the 1895 could withstand 40Kpsi. They are not required to chase down and punish any manufacturer who loads ammo past 28Kpsi. At least watch Perry Mason, Matlock, & LA Law before you spout about Marlin's legal liability.

Now to manufacturing. What makes you think that all 1895 components go through the same processing? Is it actually cheaper for Marlin to perfom the same heat treatment on all pieces, even though the extra treatment isn't required on most of them? And if Marlin is spending the extra bucks on each 1895, regardless of cartridge, to meet the high-end pressure margins for 55Kpsi cartridges, why don't they let the rest of the world know? Not making much sense.

I am reminded of all the cars that kids hot rod. Imagine all the 200+ horse power 2500lb cars on the road today. Are all the auto manufacturers telling customers that the cars are rated for 160mph? Do they release specifications showing why you are safe at 150mph? Are the manufacturers being sued out of business because they knowingly produced a car that can ridiculously exceed 70mph and sold them to morons who regularily pushed them to the limit and died in the process?

The Marlin 1895, 45-70, is NOT 40Kpsi design just because some people are using it that way. I hope at some point I hope you begin to understand this basic concept.

[w30wcf]

Please see next post.

[w30wcf]

dla,

Thank you for your response. I can understand how you feel.  The .45-70 has plenty of power at the lower pressure levels and is more pleasant to shoot,  but the fact remains that ballisticians and engineers much more knowledgeable than any of us, have established the 40,000 CUP maximum in a .45-70 Marlin 1895 of modern manufacture.  

To your question, "Is it actually cheaper for Marlin to perfom the same heat treatment on all pieces, even though the extra treatment isn't required on most of them?"   The answer is yes. To set up an additional process to perform  a different heat treating  specification   actually adds additional cost.  

Speaking of lawyers,  all of the above named companies have them.  If there was any doubt about the data, they certainly would advise them to change their  specifications.

Like yourself, I much prefer to run my .45-70 at lower pressure levels for more shooting enjoyment, but when the situation calls for it, it's nice to know that more power can be added when needed.

w30wcf

[Coyote Hunter]

dla -

The one that is lost here is yourself. But nothing new there.

Its true that Marlin doesn't encourage loading of their 1895 .45-70s past SAAMI maximum pressures. Nor does Ruger for their #1 or Browning for their 1885, etc. This is perfectly understandable from both a legal and a business management perspective, but it does NOT mean the rifles are unsafe at pressures above SAAMI's 28,000 CUP standard for the .45-70 - it just means that the manufacturers are being conservative and playing it safe. And in the case of Marlin, that they are not cannibalizing the 450 Marlin market. I've been in business management long enough to know how the game is played and have been involved in enough real life corporate legal proceedings to understand that Marlin's defensive posture is independent of the 1895's actual strength. You can bet that if the data Hodgdon, Barnes, Hornady and others were publishing, or the ammunition that Garrett, Buffalo Bore and others were producing specifically for the Marlin 1895 was unsafe, Marlin would most certainly take a legal stand to protect themselves, as failure to do so can (and would!) be construed by plaintiff's attorneys as tacit complicity on the part of Marlin.

Is it cheaper for Marlin to perform the same heat treatment on all pieces? The answer is most likely a resounding "Yes". Having spent many years in manufacturing, I understand the costs associated with creating, documenting and maintaining additional processes, and the costs associated with testing materials to those different standards. A case in point is my Nokia cell phone, which came with unlighted buttons. For a few dollars more I could have had a model with lighted buttons. Did Nokia manufacture two different base units, at tremendous additional cost? No, they simply changed a very inexpensive part, putting opaque buttons on some and transparent buttons on others. Recently I purchased transparent buttons and now have lighted buttons on my Nokia. (Gasp, I hope its still "safe"!)

Obviously you don't understand much about engineering, manufacturing, metalworking, or heat treating of metal parts. While I don't claim to be an expert, I did train and work as a machinist, and I have heat-treated numerous parts. Quite often the heat-treatment is not performed to increase strength but rather to reduce stress. No one is claiming the Marlins are safe at 55,000 PSI - rather the discussion has been about 40,000 CUP. When talking about modern steels, 40,000 CUP is not a very high pressure. From a manufacturing standpoint, the cheapest method is to forge all the receiver blanks the same, then machine them to the different requirements. The cost reduction and manufacturing flexibility benefits of doing it this way, as opposed to forging the receivers from different metals for the .30-30, .45-70 and 450 are enormous. The same is true with the barrel stock - start with the same blanks and drill and chamber according to current needs rather than maintaining different inventory for each caliber. So Marlin isn't spending "extra bucks" by producing rifles of the same relative strength - instead they are saving large sums of money by doing so.

Your argument about the cars fails to support your argument - if anything it supports exactly the opposite. The maximum speed limit here in Colorado is 75mph (SAAMI 28,000 CUP), but any driver realizes that 75mph does not necessarily represent the maximum safe speed of the vehicle. There is a reason manufacturers focus on "zero to 60mph" rather than 160mph (40,000 CUP) -- if they focused on the later and someone got killed, its a safe bet they would be sued, even though they test their vehicles and know them to be safe at speeds that "ridiculously exceed " the speed limits.

The Marlin 1895, 45-70 IS 40,000 CUP design, even though Marlin doesn't advertise it as such. And I have no hope that you will ever understand this basic concept.

[dla]

but the fact remains that ballisticians and engineers much more knowledgeable than any of us, have established the 40,000 CUP maximum in a .45-70 Marlin 1895 of modern manufacture.  

That's nice. But those experts aren't the people manufacturing the rifle.

Once in awhile Marlin ships a rifle with a poorly cut sear, or the barrel not centered, or the wrong height rear sight. What if Marlin ships a 45-70 barrel that has not been heat treated?

[dla]

Is it cheaper for Marlin to perform the same heat treatment on all pieces? The answer is most likely a resounding "Yes".......

There are cost points with every process. Taking a piece of metal from 20rc to 50rc costs money. 20rc would work for 45-70. You might be right. But I notice that Marlin is always silent.

Obviously you don't understand much about engineering, manufacturing, metalworking, or heat treating of metal parts. While I don't claim to be an expert, .......

I just did this one for fun.

......even though they test their vehicles and know them to be safe at speeds that "ridiculously exceed " the speed limits.

Now this one is blatanly wrong. Ford doesn't test each V8 Mustang for 100mph operation, and you know that. It comes off the line and they drive it to the ship lot. And they are not liable for the death of a moron wrecking it at 100+mph. Otherwise you would see any sports cars on the American market due to legal parasites.

And of course Marlin doesn't "blue pill" their 1895 either. They put it together and ship it.

[JCP]

I am by no means an expert on strength of materials but I have heat treated very much 4140. You can leave it hard 60 R-C scale which increases wear resistence or you can draw it back to 37-39 on R-C scale for max strength. It doesn't take much effort to do either. Whether they do this at marlin or not I don't know. I suspect one reason the 450 action might take a higher pressure load than the 45/70 could be the barrel threads. As I understand it the 450 has  V  shaped threads which would let the reciever bear part of the barrel's expansion load, While the 45'70 has square threads which are hard to get a tight fit on the major and minor diameter of shank. I am a machinist and do a lot of threading in the lathe . V threads can be fitted tight and normaly square threads are not. I don't know how they fit on the marlins ,I have never had either apart.

[Coyote Hunter]

There are cost points with every process. Taking a piece of metal from 20rc to 50rc costs money. 20rc would work for 45-70. You might be right. But I notice that Marlin is always silent.

Rockwell 50 isn't needed for 40,000 CUP.  What you need is tensile strength, which is different.  And you don't need all that much for 40,000 CUP.  And Marlin is silent for reason I outlined above.

...
Now this one is blatanly wrong. Ford doesn't test each V8 Mustang for 100mph operation, and you know that. It comes off the line and they drive it to the ship lot. And they are not liable for the death of a moron wrecking it at 100+mph. Otherwise you would see any sports cars on the American market due to legal parasites.

And of course Marlin doesn't "blue pill" their 1895 either. They put it together and ship it.

No, Ford doesn't test each car, nor was I suggesting that they do.  Instead they test the design and build to the specifications.  Then they test samples for compliance with the specifications, no different than with other mass production items.

Most firearm manufacturers test fire every firearm before it is shipped - I'm sure Marlin is no different, but they may very well use SAAMI-compliant  ammunition except for their proof testing.

Like I said, I have no hope you will ever grasp the simple concept.