Trapdoor Springfield Safe 45-70 Loads using Unique? Max trapdoor safe PSI?

[Remington1911]

Sure, just like having a +/- 0.3 gr variation would be disastrous for pistol.
I'm approaching this like reloading for my pistol: I know how to measure up to 0.1 gr, and I weigh each of my charges.

But by god I'd be terrified to shoot your pistol reloads if you're using a technique where you think +/- 0.3gr variation between each round is expected and acceptable.


Sure, and the Hodgdon Reloading Center data on Trapdoor Safe 45-70 only gives 3 grains margin of error difference between start and max for IMR 3031, and 2 grains margin of error difference between start and max for IMR 4198. Should I avoid these loads entirely then?
View attachment 1116696

To answer your question, on 3031 and 4190, yes I would avoid them if I had other options available.

And you don't read real well, where did I say .3 was acceptable, I said it is a larger percentage in an 11 grain load vs a 50 grain load.

If you want to put words in my mouth to try to justify what I see as a questionable decision (and trust me questionable is a very high road word for how I think about this in a 200 year old rifle) then like the other poster said, done with this.

I tried to tell you my point of view, and you chose to twist my words and cherry pick....bye now and have fun.

 

[GeoDudeFlorida]

Sorry... I missed your last question. It's 18000 PSI for BP equivalent loads.

I think this answered the question pretty well. It's also where the line has historically been drawn. Still don't know if the OP is using a nitro-proofed rifle or a black-powder-proofed rifle. Steel's strength is not in it's hardness but in its elasticity. All things weaken over time and elasticity is a transient property. Anyone who'd care to is welcome to roll the dice on metal fatigue and take their chances. Some people win that game and some lose. The loser's don't tend to talk about it much. Either through embarrassment or inability. Sounds to me like the OP's not looking for answers, which have been provided, but for an argument, which will remain on-going.

 

[AJC1]

Sure, just like having a +/- 0.3 gr variation would be disastrous for pistol.
I'm approaching this like reloading for my pistol: I know how to measure up to 0.1 gr, and I weigh each of my charges.

But by god I'd be terrified to shoot your pistol reloads if you're using a technique where you think +/- 0.3gr variation between each round is expected and acceptable.


Sure, and the Hodgdon Reloading Center data on Trapdoor Safe 45-70 only gives 3 grains margin of error difference between start and max for IMR 3031, and 2 grains margin of error difference between start and max for IMR 4198. Should I avoid these loads entirely then?
View attachment 1116696

Slow down and understand that what your seeing in the responses is an aversion to risk, and how people choose to mitigate that risk. Most equipment is accurate to +-.1 grain. So the variance could be .2 just in equipment alone. This group of guys are advocating for your safety.

 

[MEHavey]

interesting with how the pressures go

What got my attention was the rise times for BP.
It ain't so "kinder-gentler" than common-use smokeless at those pressures as is the current internet lore.

(But)... when the data disagrees w/ the theory.... so much the worse for the data.
(old experimental physicist joke)


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[GeoDudeFlorida]

Slow down and understand that what your seeing in the responses is an aversion to risk, and how people choose to mitigate that risk. Most equipment is accurate to +-.1 grain. So the variance could be .2 just in equipment alone. This group of guys are advocating for your safety.

I think this goes back to a basic misunderstanding of what is being measured by each "pressure" measuring system. CUP/LUP is measuring peak FORCE (F=ma) on a piston whose base is exposed to the burning gases and whose nose is pressed against a copper or lead pellet confined to a fixed cylinder. This system measures how much force is applied to the pellet by the piston and extrapolates pressure. PSI is measuring the STRAIN (ε = Δx/x) across Piezo-electric crystal and circuit pairing attached to the fixture whose resistance and composition is known and whose resting state is predictable. This system measures the force applied to the strain gauge as the burn process proceeds and extrapolates pressure from Δx - the change in position of the element with respect to the fixture. How "accurate" each system is depends greatly on how well the fixture represents the real-world application. I don't know about the rest of you but I really don't think I have ever or will ever shoot a Universal receiver and test barrel in the hunting fields. Maybe some BR rifles are so similar to that type of setup that the differences are irrelevant but, my Remington 30S really isn't anything like a Universal receiver/test barrel. So in a lot of ways the old, "shoot for accuracy and extraction" method found in the pre-PSI days is more "accurate" than the modern methods. For me. YMMV.

It is good to know what is behind the "science" one trusts with one's life.

 

[AJC1]

I think this goes back to a basic misunderstanding of what is being measured by each "pressure" measuring system. CUP/LUP is measuring peak FORCE (F=ma) on a piston whose base is exposed to the burning gases and whose nose is pressed against a copper or lead pellet confined to a fixed cylinder. This system measures how much force is applied to the pellet by the piston and extrapolates pressure. PSI is measuring the STRAIN (ε = Δx/x) across Piezo-electric crystal and circuit pairing attached to the fixture whose resistance and composition is known and whose resting state is predictable. This system measures the force applied to the strain gauge as the burn process proceeds and extrapolates pressure from Δx - the change in position of the element with respect to the fixture. How "accurate" each system is depends greatly on how well the fixture represents the real-world application. I don't know about the rest of you but I really don't think I have ever or will ever shoot a Universal receiver and test barrel in the hunting fields. Maybe some BR rifles are so similar to that type of setup that the differences are irrelevant but, my Remington 30S really isn't anything like a Universal receiver/test barrel. So in a lot of ways the old, "shoot for accuracy and extraction" method found in the pre-PSI days is more "accurate" than the modern methods. For me. YMMV.

It is good to know what is behind the "science" one trusts with one's life.

Well we know that top end loads of 357 mag will lossen up a pistol even if we don't have the metal fatigue analysis. I love old guns and have a few, rapid disassembly is not on the "to do" list. One brass spray to the face was more than enough for this guy, and I'm fully engaged in no repeats.

 

[Charlie98]

2) I've used it successfully at lower charges (see the 10-12 gr for 405, and 12-14 gr for 300 discussion above), and I want to know where the safe maximum is. For example, The Lyman 44 scan I posted above tells me it's 15 gr for a 385 bullet, which QL calculates at 24,000 PSI -- which should fall within the 28,000 SAAMI limit. But that's also why I'm asking on an internet forum to see if anyone else has done it before before trying it myself.

I guess you missed the part where I said 18K is the general smokeless limit for a vintage Trapdoor. And, yes, I understand there is conflicting data (and opinions, including mine...) on this. The limited amount of research I've done in the past day or so, based on this question, leads me to rethink my position on running smokeless in something like a Trapdoor, but the general consensus was to limit the loads to 18K PSI.

"Faster" powders will drop off their pressure quicker then "slower" powders.

To answer your question, on 3031 and 4190, yes I would avoid them if I had other options available.

I would have to question your comments, however. I posted 2 loads... the 15grn Unique load, and my 30grn IMR4198 load, both under the same 405grn cast bullet, for roughly the same velocity. The 15grn Unique load peaks faster and then drops quickly, but at nearly 25K PSI, where the IMR4198 load, while holding the pressure longer, only peaks at roughly 15K PSI. I'm not a metallurgist... but explain to me why a much higher pressure is advantageous over a lower one, even if it's drawn out?

 

[MEHavey]

CUP is -- in effect -- the integrated pressure/time effect on a material: "What happened"
PSI is digital (or analog trace) of pressure per unit time: "What's happening"

You can with some considerable strength of materials data and 3D hydrocode machinations relate the two...
but it ain't worth it.


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[MEHavey]

explain to me why a much higher pressure is advantageous over a lower one

In a great many cast bullet loadings, using a fast powder/getting a fast rise time is key to quick bore/bullet sealing.
It's also a trade-off w/ bullet alloy -- against initial sealing -- and hanging on to the rifling as velocity rises as well.
Artful magic, it is.


(Using that magic even now on a traditional 330 Gould/BushMaster combo as I type)

 

[applefish123]

Slow down and understand that what your seeing in the responses is an aversion to risk, and how people choose to mitigate that risk. Most equipment is accurate to +-.1 grain. So the variance could be .2 just in equipment alone. This group of guys are advocating for your safety.

I weigh each charge on a digital scale, and then verify with an RCBS 10-10. Maybe it's because I'm new and i'm not used to the culture of this forum, but do I need to post a picture of my reloading setup each time discussing a historical published load on this website?

Quickload tells me the difference between 13 gr and 13.2 gr of unique with a 405 in a 45-70 is 500 PSI: from 19,800 to 20,300. These both fall far below the 28,000 SAAMI spec, as well as far below the hodgdon's recommended loads using other powders and projects.
I'm not asking about how many 100's of PSI I can creep over max. I'm asking what the real max is, and where it was established: and why Hodgdon would recommend loads going up to 27,000 CUP in the category of "45-70 Government (Trapdoor Rifles)"

If you don't believe me (it seems like every damn time I need to post a screenshot from a book to "prove" to you guys that a load is published), try it for yourself here: https://www.hodgdonreloading.com/reloading-data-center

To answer your question, on 3031 and 4190, yes I would avoid them if I had other options available.

By your logic I should be safer with IMR 4064, where the starting load is 46.0 gr and and gives me a wider "margin of error". But that already starts at 21,000 CUP for trapdoor safe loads, well above the so-called 18,000 CUP cutoff.

So are you recommending I follow the most recent published data from Hogdon's Reloading Center website and start at 21,000 CUP (and goes up to 27,400 CUP), instead of the ones I've been using at ~17,000-19,000 CUP?

Hey like you said, it'll increase my margin of error by starting with 46.0 grains instead of the 11gr i'm loading with unique.

I think this answered the question pretty well. It's also where the line has historically been drawn

Historically, Lyman 44 recommended 11-15 grains of Unique for trapdoor safe loads. So historically, 15 grains of Unique on a 385 lead bullet is safe.
So where's the problem?

Still don't know if the OP is using a nitro-proofed rifle or a black-powder-proofed rifle.

US government loaded smokeless for all trapdoors in 1898, so I wouldn't be the first.
https://www.oldammo.com/november04.htm

 

[GeoDudeFlorida]

Bottom line: both PSI are CUP are extrapolating pressure from change in position. That's nice - all sciencey and everything - but what does it mean in practical terms for a firearm of unknown origin and history? Not a lot. It's just like the gamblers who use "a system" to lose more, faster.

 

[AJC1]

I weigh each charge on a digital scale, and then verify with an RCBS 10-10. Maybe it's because I'm new and i'm not used to the culture of this forum, but do I need to post a picture of my reloading setup each time discussing a historical published load on this website?

Quickload tells me the difference between 13 gr and 13.2 gr of unique with a 405 in a 45-70 is 500 PSI: from 19,800 to 20,300. These both fall far below the 28,000 SAAMI spec, as well as far below the hodgdon's recommended loads using other powders and projects.
I'm not asking about how many 100's of PSI I can creep over max. I'm asking what the real max is, and where it was established: and why Hodgdon would recommend loads going up to 27,000 CUP in the category of "45-70 Government (Trapdoor Rifles)"

If you don't believe me (it seems like every damn time I need to post a screenshot from a book to "prove" to you guys that a load is published), try it for yourself here: https://www.hodgdonreloading.com/reloading-data-center

View attachment 1116702



By your logic I should be safer with IMR 4064, where the starting load is 46.0 gr and and gives me a wider "margin of error". But that already starts at 21,000 CUP for trapdoor safe loads, well above the so-called 18,000 CUP cutoff.

So are you recommending I follow the most recent published data and start at 21,000 CUP, instead of the ones I've been using at ~17,000-19,000 CUP?


Historically, Lyman 44 recommended 11-15 grains of Unique for trapdoor safe loads. So historically, 15 grains of Unique on a 385 lead bullet is safe.
So where's the problem?


US government loaded smokeless for all trapdoors in 1898, so I wouldn't be the first.
https://www.oldammo.com/november04.htm

View attachment 1116703

OK let's take this another way. Do you know why CIP limits are higher...

 

[applefish123]

OK let's take this another way. Do you know why CIP limits are higher...

Jesus, and an intelligence test each time I want to post on this forum.

Do I need to get a PhD in engineering with a specialization in interior ballistics to post on this forum? Man I must've been spending time on the wrong reloading forums in the past, I never knew you guys held such high knowledge standards for each other!

Here, here you go. Or do you need me to break out the dusty old interior ballistics textbook to walk you through the differences between these two?

 

[MEHavey]

why Hodgdon would recommend loads going up to 27,000 CUP in the category of "45-70 Government (Trapdoor Rifles)"

Because CUP = PSI for the 'standard' 45-70 (only)
https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf
pages 22 & 34


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[applefish123]

Because CUP = PSI for the standard 45-70 (only)
https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf
pages 22 & 34

Finally someone with enough sense to actually bother reading the test data!

But apparently because everyone else here doesn't have the time to look up the actual data, I'll post convenient screenshots:





I don't know about you, but that "28,000 CUP" table looks awful similar to the "28,000 PSI" table

But maybe my eyes are getting old and I should be listening to the people telling me how CUP is not PSI for the 45-70...

 

[MEHavey]

Don't over-categorize me with 'sense'
My wife says it's only evident when she says so....

 

[Soonerpesek]

I'm not asking about how many 100's of PSI I can creep over max. I'm asking what the real max is, and where it was established: and why Hodgdon would recommend loads going up to 27,000 CUP in the category of "45-70 Government (Trapdoor Rifles)"

If you don't believe me (it seems like every damn time I need to post a screenshot from a book to "prove" to you guys that a load is published), try it for yourself here: https://www.hodgdonreloading.com/reloading-data-center

Nothing on the chart you supplied lists 27,000 CUP.............

 

[MEHavey]

postscript from Buffalo Bore, re SAAMI:

We believe that SAAMI got it wrong with the 45-70 govt. cartridges, to state
that 28,000 CUP is OK to fire in trapdoor actions. We believe you can
damage the basic 1873 Trapdoor action (regardless of vintage) with loads
that exceed 20,000 CUP. We are not stating that you definitely will damage
Trapdoor actions with ammo that runs 28,000 CUP, but we know that it can
happen, so while this ammo is operating at or under the SAAMI limit of
28,000 CUP, we warn against using it in the 1873 Trapdoor Springfield
action or modern reproductions thereof.

So take care.... These are people who have to put their mouth where their money is...


,

 

[applefish123]

Nothing on the chart you supplied lists 27,000 CUP.............

You're right, it reads 27,400 CUP



I have to apologize, my eyes are getting old, but I'm pretty sure it reads "trapdoor rifles" and "27,400 CUP".
Here, try it for yourself: you guys keep recommending me I should follow the latest and greatest manufacturer's reloading data, right?

https://www.hodgdonreloading.com/reloading-data-center

 

[MEHavey]

-- delete, as

Nothing on the chart you supplied lists 27,000 CUP...

You are correct.
Hodgdon listed 27,400 CUP



That said, as a devout coward I counsel we listen to BuffBore as a matter of practical trapdoor limits.

.

 

[Soonerpesek]

You're right, it reads 27,400 CUP

Ummmm........it reads 27,400 PSI..........



fish, varmint, dog...........................................................I'm starting to see a correlation here.............

 

[Jim Watson]

Ken Waters was wary of those pistol powder loads, considering Unique and even 2400 to be too spiky.
He thought 4198 and 3031 more suitable.
I know you won't find me putting Trail Boss in a BPCR.

Those old manuals like the Lyman 44th did not have pressure tested loads, just what eyeball and micrometer told them was OK in the typical firearm they had at hand.

Phil Sharpe showed two load levels for .45-70-405 nitro, say 14000 and 24000 for #2400.
He also tabulated .45-70-500 really 70 gr Fg at 25000 as determined for him by Hercules before WWII.

The first edition Accurate Arms manual showed loads for some of the old non-SAAMI BPCRs, based on firing with black. I RECALL a number of 24000. So they used that as a maximum for their smokeless data.

 

[applefish123]

Ummmm........it reads 27,400 PSI..........

Well my god you're right, my eyes really are worse than they were.

Good thing quickload calculates things in PSI, that's very reassuring since I don't need to worry about the error or "lossiness" around trying to convert CUP to PSI then.
So by Hodgdon's logic, is 27,400 PSI is safe in a trapdoor, then 20,000 psi should definitely be safe!
So why is this forum getting so upset that i'm staying within the pressure bounds of the latest and greatest reloading data?

 

[MEHavey]

Ken Waters was wary of those pistol powder loads, considering Unique and even 2400 to be too spiky.

As shown in recent actual pressure-trace data -- now shown to be another one of those settled science facts . . .
that warn't so settled
(Post #20)



.

 

[Soonerpesek]

Good thing quickload calculates things in PSI, that's very reassuring since I don't need to worry about the error or "lossiness" around trying to convert CUP to PSI then.
So by Hodgdon's logic, is 27,400 PSI is safe in a trapdoor, then 20,000 psi should definitely be safe!
So why is this forum getting so upset that i'm staying within the pressure bounds of the latest and greatest reloading data?

What it sounds like is you are trying to convince us to tell you that your loading will be okay..........
The majority of us (although I can only truly speak for myself ) are only concerned with safety of the loader and the gun......
I'm assuming you are a big boy and can do whatever you want without our approval......
Good luck and I wish you find a loading that works perfect for you......