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

[applefish123]

Does anyone know any trapdoor safe loads with Unique? And what is the maximum safe PSI for these originals?

In my old Lyman 44 they list:

• For 292 gr cast, 18gr (1497 fps) to 20 gr (1689 fps)
• For 385 gr cast, 14gr (1244 fps) to 17 gr (1408 fps)
• For 482 gr cast, 13gr (1112 fps) to 16 gr( 1242)

But for some reason these loads don't appear in the newer manuals I have.

Quickload is telling me that the pressures for the old Lyman 44 loads run around 25,000 psi. And if you look at the hodgdon data center online today, they'll list a bunch of jacketed loads running around 25,000-27,000 psi for the trapdoor. And the cast loads run around 16,000-22,000 psi.

However my modern Lyman 48 manual doesn't show any load going above 18,000 psi in the trapdoor; they write: "Overzealous reloaders have destroyed more than one Trapdoor through high-pressure loads. The following data is held to a pressure level of 18,000 CUP for use in the Model 1 873 Trapdoor. It is also suitable for Remington Rolling Blocks, Sharps Rifles and replicas of any of these rifles as well as the Harrington & Richardson Trapdoor." Lee also follows the 18,000 psi limit for their trapdoor loads.


So who is right about the maximum trapdoor safe load, SAAMI, CIP, and Hodgdon's Reloading Center at ~28,000 psi, or Lyman and Lee at 18,000 CUP?

 

[Charlie98]

Part of the problem is trying to extrapolate CUP data into PSI... and, besides the 'overzealous' loaders, I think that's where some of the problem lies. Basically speaking, you can't convert CUP to PSI... you have to retest for data.

The one tried and true Unique load I know of is a cast 405grn over 15grn Unique. I get 1200fps or so with that, out of my 32" Pedersoli 1885, and according to QL, that load is just under 25K PSI. The data model QL provides is pretty close to what I get from my 1885, so I trust it. I have not tried Unique under the 385grn bullet, or anything lighter.

Looking at your 3 loads, I would run them through QL first. I show 20grn Unique under that 292grn cast pushing nearly 29K PSI!

FWIW, even though I've done it, I'm not a big fan of Unique in that big .45 case. I prefer to use more appropriate powders that give better case fill, and don't have such a volatile pressure curve... like IMR4227 or IMR4198. I think IMR4198 (and it's similar companion AA5744) are the perfect powder for Trappy level loads in the .45-70. I would (I have) even used powders like 2400... which I'd take every day and twice on Sunday over Unique. And understand, and as you might have guessed by my avatar... I LOVE Unique, but I also know it has it's place. I don't think that place is in the .45-70 case.

My standard load with a 405grn cast bullet, is 30grn IMR4198. With that I get the same basic velocity (1250fps) as the Unique load, but at a very easy 15K PSI. IMHO, it's simply a better solution.

 

[Charlie98]

So who is right about the maximum trapdoor safe load, SAAMI, CIP, and Hodgdon's Reloading Center at ~28,000 psi, or Lyman and Lee at 18,000 CUP?

The no-nonsense answer to your question is 'the most modern data.' That would be Hodgdon, et al.

 

[applefish123]

I should probably add some context, I've loaded using unique

• 405's with 10 gr (chronoed 1000 fps, it's a nice subsonic load!) to 12 gr unique (1100 fps). Quickload tells me 12 gr has a PSI of 17,000
• 300's with 12 gr (chronoed 1230 fps) to 14 gr (chronoed 1365 fps). Quickload tells me 14gr has a PSI of 17,000

I'm asking because I loaded up a ladder test to 13 gr of unique with the 405 (Quickload is saying 20,000 PSI) and 15 gr of unique with the 300 (quickload is saying 19,000 psi).
And I'm debating whether or not its worth pulling the bullets because they're above Lyman and Lee's 18,000 CUP/PSI cutoff, or if it's alright to run these over the chronograph because they fit well within SAAMI/CIP/Hodgdon's 28,000 PSI cutoff.

Part of the problem is trying to extrapolate CUP data into PSI..

I should clarify, the LEE modern reloading manual I have lists pressures in PSI. Lyman lists in CUP. But they're both around 18,000 PSI/CUP max.

This is very different from Hodgdon loading center data under the "45-70 Government (Trapdoor Rifles)" section that seems to follow SAAMI/CIP guidelines of ~28,000 PSI. But they don't have any data for Unique because that's made by alliant

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

The no-nonsense answer to your question is 'the most modern data.' That would be Hodgdon, et al.

Do you know why Lyman would include hot loads in their early handbooks, but now only advises a max of 18,000 CUP in their most recent editions?

 

[Charlie98]

they're above Lyman and Lee's 18,000 CUP/PSI cutoff,

Do you know why Lyman would include hot loads in their early handbooks, but now only advises a max of 18,000 CUP in their most recent editions?

First... understand that there is a huge difference between CUP and PSI. They are not parallel, they can't be reliably extrapolated from one to another. Now, I've seen... even in Hodgdon's data... CUP loads listed with PSI loads, that's the nature of the beast. CUP readings usually represent older data, PSI newer data with newer, more precise equipment and methodology, that's why you take newer PSI data over older CUP data if you can... it's simply better, more accurate data.

The discrepancy in Lyman data was probably because they realized some of the older CUP data was too hot... whether or not they blamed it on overzealous reloaders. A reduction in data limits is the safe thing to do.

 

[Charlie98]

This is very different from Hodgdon loading center data under the "45-70 Government (Trapdoor Rifles)" section that seems to follow SAAMI/CIP guidelines of ~28,000 PSI. But they don't have any data for Unique because that's made by alliant

You will also note, besides TrailBoss, Hodgdon does not list a pistol powder for the .45-70, even lowly Trappy data. Neither does Alliant. I think there is a reason for that.

 

[GeoDudeFlorida]

PSI is not CUP and vice-versa. You can’t mix the two.
When you say, “...in these originals,” I take that to mean you are loading for a Black Powder proofed rifle. If so, any loads with smokeless are not going to be particularly “good” for your action. Yes I understand, “but everybody does it!” And that’s the problem Lymans is pointing out. If it’s a black powder proofed rifle, shoot black powder or equivalent. If it’s proofed for smokeless, load using the most modern data available and ALWAYS start at the minimum load and work up to your accuracy/velocity goal. It also matters why you’re doing this: targets, plinking, hunting, just for gits and shiggles, etc.?

 

[Charlie98]

And that’s the problem Lymans is pointing out. If it’s a black powder proofed rifle, shoot black powder or equivalent.

...and I forgot to axe that question.

 

[Remington1911]

I can tell you what I do, and I went down this road about a year or so ago and found a loading my trapdoor likes and that I am comfortable with.

The load I settled on is for a VV powder (darn if I can remember the number but if you want I will dig it up when I get home) I don't remember where the load I am using came from, but I can tell you that quick load says it is in the 14k range....I like that.

I was told you want to stay UNDER 18 and be in the mid teens is possible. I am sending a 405 grain, at roughly (i want to say but could be wrong, old man memory) 900-ish FPS with minute of native american accuracy at 100 yards. (it is what the rifle was used for, and I am native, so ease up)

I am not a fan of the powders you list for this application, but then again I am not a fan of the people with "modern" 45-70's what I see as hand gun powders in them.

 

[GeoDudeFlorida]

I should probably add some context, I've loaded using unique

• 405's with 10 gr (chronoed 1000 fps, it's a nice subsonic load!) to 12 gr unique (1100 fps). Quickload tells me 12 gr has a PSI of 17,000
• 300's with 12 gr (chronoed 1230 fps) to 14 gr (chronoed 1365 fps). Quickload tells me 14gr has a PSI of 17,000

I'm asking because I loaded up a ladder test to 13 gr of unique with the 405 (Quickload is saying 20,000 PSI) and 15 gr of unique with the 300 (quickload is saying 19,000 psi).

I’m not sure I understand: You have two good loads you’ve chronographed and tested in your rifle. Why are you looking to go higher? Also, you have Quickloads and you have your rifle. You can check your rifle’s manufacturer’s site and get the specifications - unless it’s a black powder rifle which brings me back to, load black powder or a black powder equivalent. Loading smokeless - even Unique - is rolling the dice on metal fatigue and the limits of steel elasticity.

 

[.455_Hunter]

The NEWEST original Trapdoor is 130 years old. I am moving to shooting mine only with BP (preferred) or smokeless loads that are most optimal, NOT what might work with a non-ideal configuration.

 

[applefish123]

First... understand that there is a huge difference between CUP and PSI. They are not parallel, they can't be reliably extrapolated from one to another. Now, I've seen... even in Hodgdon's data... CUP loads listed with PSI loads, that's the nature of the beast. CUP readings usually represent older data, PSI newer data with newer, more precise equipment and methodology, that's why you take newer PSI data over older CUP data if you can... it's simply better, more accurate data.

PSI is not CUP and vice-versa. You can’t mix the two.

I'm well aware of that. And Lyman lists 18,000 CUP. And Lee lists 18,000 PSI.
and SAAMI lists 28,000 CUP, and CIP lists 2,200 BAR which is 31,000 PSI.

Please re-read what i've read. If you don't believe me here's all the proof that, at these pressures, CUP and PSI are very close. But I'm not talking about doing some mumbo-jumbo napkin math to equate them. I'm talking about LYMAN's measured and tested 18,000 CUP limit and LEE's measured and tested 18,000 PSI limit. Versus SAAMI's measured and tested 28,000 CUP limit and CIP's measured and tested 31,000 PSI limit (we'll round down to 28,000 for safety).


Lyman uses 18,000 CUP as limit:


Lee uses 18,000 PSI as limit



SAAMI uses 28,000 CUP as limit


CIP uses 2,200 BAR or 31,000 PSI as limit



I don't understand what's so difficult to understand about that.

 

[applefish123]

I’m not sure I understand: You have two good loads you’ve chronographed and tested in your rifle. Why are you looking to go higher? Also, you have Quickloads and you have your rifle. You can check your rifle’s manufacturer’s site and get the specifications - unless it’s a black powder rifle which brings me back to, load black powder or a black powder equivalent. Loading smokeless - even Unique - is rolling the dice on metal fatigue and the limits of steel elasticity.

I loaded up a ladder of 10-13 grains of Unique for the 405 bullet and 12-15 grains of Unique for the 300 grain bullet.
I've pushed this ladder to the ~17,000 quickload PSI limit, and I want to know if I can take it up the next grain to ~19,000/20,000 PSI safely.

So has anyone done that before, 13 gr of Unique on 405gr cast lead, or 15 gr of Unique on 300gr cast lead in a trapdoor?

Surely I'm not the only one here, since the older Lyman manual included this data. Unless you all are a lot younger than I am!

The NEWEST original Trapdoor is 130 years old. I am moving to shooting mine only with BP (preferred) or smokeless loads that are most optimal, NOT what might work with a non-ideal configuration.

Yes and with a 405 gr bullet I get 1275 fps with 55 gr swiss and around 1350 with 70 grains swiss.
And I have a BP equivalent load with 30 grs IMR 4198 giving around 1350 fps with the 405 grain bullet.

Just because I want to load with unique doesn't mean I'm scared of shooting with black powder. I've tried both goex and swiss and know how to load black powder. I didn't create this discussion to be told "no stop being scared of black powder it's not so bad to clean" because I've done it before. I created this discussion to ask about:

1. People's experience using unique in trapdoor safe 45-70 loads, and
2. The discrepancy between 18,000 PSI/CUP recommended by lyman and lee versus the ~28,000 CUP/31,000 PSI recommended by SAAMI/CIP/Hodgdon.

 

[GeoDudeFlorida]

I'm well aware of that. And Lyman lists 18,000 CUP. And Lee lists 18,000 PSI.
and SAAMI lists 28,000 CUP, and CIP lists 2,200 BAR which is 31,000 PSI.

Please re-read what i've read. If you don't believe me here's all the proof that, at these pressures, CUP and PSI are very close. But I'm not talking about doing some mumbo-jumbo napkin math to equate them. I'm talking about LYMAN's measured and tested 18,000 CUP limit and LEE's measured and tested 18,000 PSI limit. Versus SAAMI's measured and tested 28,000 CUP limit and CIP's measured and tested 31,000 PSI limit (we'll round down to 28,000 for safety).


Lyman uses 18,000 CUP as limit:
View attachment 1116527

Lee uses 18,000 PSI as limit
View attachment 1116528


SAAMI uses 28,000 CUP as limit
View attachment 1116529

CIP uses 2,200 BAR or 31,000 PSI as limit
View attachment 1116530


I don't understand what's so difficult to understand about that.

You’re on your own, dude.

 

[Remington1911]

I'm well aware of that. And Lyman lists 18,000 CUP. And Lee lists 18,000 PSI.
and SAAMI lists 28,000 CUP, and CIP lists 2,200 BAR which is 31,000 PSI.

Please re-read what i've read. If you don't believe me here's all the proof that, at these pressures, CUP and PSI are very close. But I'm not talking about doing some mumbo-jumbo napkin math to equate them. I'm talking about LYMAN's measured and tested 18,000 CUP limit and LEE's measured and tested 18,000 PSI limit. Versus SAAMI's measured and tested 28,000 CUP limit and CIP's measured and tested 31,000 PSI limit (we'll round down to 28,000 for safety).


Lyman uses 18,000 CUP as limit:
View attachment 1116527

Lee uses 18,000 PSI as limit
View attachment 1116528


SAAMI uses 28,000 CUP as limit
View attachment 1116529

CIP uses 2,200 BAR or 31,000 PSI as limit
View attachment 1116530


I don't understand what's so difficult to understand about that.

Perhaps I am blind....well I am old and have trouble seeing anymore. But I don't see a load listed for Unique in the photos you posted. Why do you want to use Unique? I am going to guess it is the same reason people with "modern" like to use these powders.....you use less of it. 13 grains is a lot cheaper then 33 grains of 4198, or 50 something of varget. If that is your reason I don't think it is a real good reason. Like another poster said these are some old ladies and we do need to take care in feeding them. I see the appeal of black powder, it is what it was designed around. However black powder does have some down sides as well, and I feel that modern smokeless with modern primers at the correct pressures there is no danger to you or the rifle.....well no more danger in shooting any other rifle that is 100+ years old that is in like shape. I would also stick with lead bullets, no jackets.

My advice is don't do the Unique just to save a penny it is not worth the risk. And another note in the shortage filled times we are living in, with pressures in the teens large magnum hand gun primers are something you may want to look into as well if you happen to have them laying around and like shooting your trapdoor more then big hand guns.

 

[applefish123]

Perhaps I am blind....well I am old and have trouble seeing anymore. But I don't see a load listed for Unique in the photos you posted. .

From Lyman 44: "These loadings are intended for single shot 45/70 rifles which have trap door actions"

385 Grain Cast
Starting: 11.0 gr Unique - 1048 fps
Max: 15.0 gr Unique - 1335 fps

13 Grains on a 405 is sticking 2 grains under the old Lyman 44 maximum.
And 15 grains on a 300 is the same charge weight, but with a bullet 25% lighter and with greater case capacity.

and I feel that modern smokeless with modern primers at the correct pressures there is no danger to you or the rifle.....well no more danger in shooting any other rifle that is 100+ years old that is in like shape. I would also stick with lead bullets, no jackets.

That's what i'm asking. What are the "correct pressures"? Is it 18,000 CUP or PSI, or 28,000 CUP or 31,000 PSI?

 

[Charlie98]

(Deleted)

 

[Charlie98]

That's what i'm asking. What are the "correct pressures"? Is it 18,000 CUP or PSI, or 28,000 CUP or 31,000 PSI?

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

 

[Remington1911]

You still have not said the why you want to use it.

I am also done till I see a reason why.

The margin of error is so small with lighter powder loads. a .3 grain is huge in an 11 grain load. It is not as impactful on a 50 grain load.

 

[MEHavey]

you can't convert CUP to PSI.

Does anyone want to dispute that the 45-70 is one of very (very very) few where psi = CUP limits?
https://www.shootingsoftware.com/ftp/psicuparticle2.pdf

As to the God's Truth of smokeless "spike" vs BP gentle... see
https://sites.google.com/view/44win...ballistics-handloading/pressure-testing?pli=1
(my old dog eyes were opened)

Bottom line is that while I'm an old (and hopefully going to get much older) BPCR shooter, I don't turn up my nose at 12-13gr Unique under a Lyman 405 anymore.



,

 

[applefish123]

The margin of error is so small with lighter powder loads. a .3 grain is huge in an 11 grain load. It is not as impactful on a 50 grain load.

Are you telling me you guys get 0.3 grain variations in your powder throws? How do you load for pistol then?
In the small caliber pistol cartridges like 32 S&W Long and 38 S&W, 0.3 grains is the difference between a starting and max load.



I appreciate the concern, but I know enough on how to use a powder scale to ladder test by 0.1 gr increments for my pistol cartridges like 38 S&W that have as little as 12 gr of water case capacity. So i'm not particularly concerned about accidentally throwing .3 gr variations in a 45-70 case that has 80 gr of water case capacity, since I weigh my charges to the 0.1 gr anyways.

Though I am concerned on how you've ever survived reloading pistol if you're regularly throwing charges with +/- 0.3 gr variation...

You still have not said the why you want to use it.

1) It's what I have lots of on hand
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.
3) Because it's historically been done. And for a forum dedicated to discussing reloading, I'm surprised there's much any discussion going on if the default answer is "follow to a T only the most recent latest greatest manual™ published within the last 5 years, and disregard any other historical reloading manuals that are older than 10 years old"

 

[Remington1911]

Are you telling me you guys get 0.3 grain variations in your powder throws? How do you load for pistol then?
In the small caliber pistol cartridges like 32 S&W Long and 38 S&W, 0.3 grains is the difference between a starting and max load.

View attachment 1116693

I appreciate the concern, but I know enough on how to use a powder scale to ladder test by 0.1 gr increments for my pistol cartridges like 38 S&W that have as little as 12 gr of water case capacity. So i'm not particularly concerned about accidentally throwing .3 gr variations in a 45-70 case that has 80 gr of water case capacity, since I weigh my charges to the 0.1 gr anyways.

Though I am concerned on how you've ever survived reloading pistol if you're regularly throwing charges with +/- 0.3 gr variation...



1) It's what I have lots of on hand
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 (The Lyman 44 scan I posted above tells me it's 15 gr for a 385 bullet, which QL calculates at 24,000 PSI -- but that seems a bit too hot for me).
3) Because it's historically been done. And for a forum dedicated to discussing reloading, I'm surprised there's much any discussion going on if the default answer is "follow to a T only the most recent latest greatest manual™ published within the last 5 years, and disregard any other historical reloading manuals that are older than 10 years old"

I am telling you that the margin for error is smaller, and that the same error on an 11 grain load is a larger percentage over a 50 grain load.....that is just math.

One of the things I do when loading is I want the smallest margin for error, I am not saying you can't do it, I am saying doing it for the sole reason of saving a penny is not a good reason.

I understand in the shortages of today we want to use what we have on hand, and why I went to magnum pistol primers in my 45-70 loads, something I would NEVER have done before....something I would not have thought twice about....these shortages push us into making some decisions that we would not otherwise make. Had a story going with another guy on a forum talking about issues in a car he bought for his daughter, and he said he never bought a car with 100k miles on it before, you bought it because where the world is right now, your hand is forced....it is a 100k car or no car.

With powder like this, you have "lots" on hand, and yes you can use it, it is listed in the manual. I don't think it is the smart thing to do. If I was in your shoes, and I do love shooting my trapdoor, it is just so mechanical to me, just puts a smile on my face... I would let it sit if Universal was all I had.

You have "lots", but is it your only choice. If you have other choices that is where (I) would go. If it is my only choice, I personally would let the rifle sit till I came across some other powder that I am more comfortable with.

 

[Remington1911]

I am telling you that the margin for error is smaller, and that the same error on an 11 grain load is a larger percentage over a 50 grain load.....that is just math.

One of the things I do when loading is I want the smallest margin for error, I am not saying you can't do it, I am saying doing it for the sole reason of saving a penny is not a good reason.

I understand in the shortages of today we want to use what we have on hand, and why I went to magnum pistol primers in my 45-70 loads, something I would NEVER have done before....something I would not have thought twice about....these shortages push us into making some decisions that we would not otherwise make. Had a story going with another guy on a forum talking about issues in a car he bought for his daughter, and he said he never bought a car with 100k miles on it before, you bought it because where the world is right now, your hand is forced....it is a 100k car or no car.

With powder like this, you have "lots" on hand, and yes you can use it, it is listed in the manual. I don't think it is the smart thing to do. If I was in your shoes, and I do love shooting my trapdoor, it is just so mechanical to me, just puts a smile on my face... I would let it sit if Universal was all I had.

You have "lots", but is it your only choice. If you have other choices that is where (I) would go. If it is my only choice, I personally would let the rifle sit till I came across some other powder that I am more comfortable with.

Edit to add, I think I am safe in saying that any modern hand gun is going to be stronger then a rifle with the back half of the barrel wacked off. The trapdoor has not a lot of room before something bad can happen.

 

[applefish123]

I am telling you that the margin for error is smaller, and that the same error on an 11 grain load is a larger percentage over a 50 grain load.....that is just math.

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.

One of the things I do when loading is I want the smallest margin for error, I am not saying you can't do it, I am saying doing it for the sole reason of saving a penny is not a good reason.

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?

 

[Remington1911]

Does anyone want to dispute that the 45-70 is one of very (very very) few where psi = CUP limits?
https://www.shootingsoftware.com/ftp/psicuparticle2.pdf

As to the God's Truth of smokeless "spike" vs BP gentle... see
https://sites.google.com/view/44win...ballistics-handloading/pressure-testing?pli=1
(my old dog eyes were opened)

Bottom line is that while I'm an old (and hopefully going to get much older) BPCR shooter, I don't turn up my nose at 12-13gr Unique under a Lyman 405 anymore.



,

I slimmed the article you linked, book marked it to go back and "really read" it. Sounds interesting with how the pressures go, and kinda lines up with what I had been thinking for a while now. "Faster" powders will drop off their pressure quicker then "slower" powders. The only question I have is when is a gun (most likely) whatever that means to fail. Is it like a light bulb that is more likely to blow when you flip the switch, or will having to hold that pressure in for longer (we are talking micro sec here) will having to hold that pressure longer cause the failure. I would lean to the initial spike from an "at rest" pressure to the high pressure is where failure is going to happen. We have a few other things to think about in that longer time frame, heat for one, and that would be an interesting test as well. Is a gun more likely to fail if it is hot or at room temp....hot as if shooting 10 rounds in under a minute kind of thing, and room temp being a human comfortable temp.

Like I said above, yea you can do it, (I) will not. If 12-13 grains of Unique are ok, how about 5 grains of tight group....another common loading for people in the 45-70 world.