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Thread: Trapdoor Strength

  1. #1
    Boolit Master
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    Last edited by Buckshot; 09-03-2009 at 01:08 AM.
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  2. #2
    Boolit Master
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    The army when testing trap doors with Krag barrels and ammo found that the rifle would hold the pressure but after a couple thousand rounds the breach block was getting loose so they figured it was not soldier proof enough so never converted the guns to Krag ammo.

  3. #3
    Boolit Master
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    Interesting photo of the barrel failure on page 67 of the second article. If there was a ductile failure, it would be smooth looking with part of the failure showing stretch marks. I don't see that here. It looks like the surface of the break was crystalline.

    There are only two reasons (that I know of) that would cause a crystalline looking break in steel. One is that the metal is brittle like iron, or steel with too much carbon. The other is that it was caused by fatigue.

    I don't believe it is fatigue in this case. First, the number of rounds that it would take to cause fatigue is more than could be fired in a gun -- many hundreds of thousands of rounds. The other reason is that if it was a fatigue failure, it would show the final failure as ductile. In other words, the break would look crystalline until there was not enough metal left to hold the pressure. Then it would stretch and pull apart. I don't see that in the photo.

    The article mentions free machining steel. The free machining steel I have seen fails in a ductile manner. One of the most common ways to make steel machine more easily is to add lead. I believe that this is made from either iron or some kind of steel that has more carbon than it should have (essentially zero ductility in either case).

  4. #4
    Boolit Master
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    I was suprised at the load of Bullseye it took to destroy the trapdoor. I can't imagine what the recoil would have been!

    I grew up hearing about how weak the Trapdoors were and believed them with out ever knowing what the test were that determined weakness. Then I read Waters article on the 45-70 in Rifle and Handloader magazines and he had four (4) load levels for the 45-70 with the trapdoor in the lowest tier. Several others also did loading guides and the Trapdoor was always in the bottom tier. Too weak, etc. I wonder what the basis for the determination was as reading these pages it seems to indicate the Trapdoor is a bit stronger, and safer, than was previously thought.

    I guess my ideas of rebarreling a Trapdoor will get a fresh turn.
    Last edited by StrawHat; 12-29-2011 at 06:19 AM.
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  5. #5
    Boolit Master
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    Does anyone know of a way to get the article printed on this thread? Instead of the links. If someone can do it, please do so, I am not that savvy with a computer. Thanks.
    Knowledge I take to my grave is wasted.

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  6. #6
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    I just clicked on the links, told my computer to open. This opened a Word file with extra pages. I printed them out of Word.
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  7. #7
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    I'm not a super expert on single shot actions but I do have some experience with the Trapdoor, rolling block, Martini, and Sharps. Out of these the rifle with, by far, the most positive extraction and the only one with an ejector is the Trapdoor. The Trapdoor also has, by far, the best camming action to seat a stubborn cartridge. I haven't had a cartridge leak gas in any of these rifles, however I do believe I'd much prefer to be shooting a Trapdoor than a rolling block if it happened. For a battle rifle the good old Springfield seems better able to cope with bad ammo and dirt than any of the others. Its biggest fault as I see it is the tendancy of the breech block to bounce back when it's rapidly opened or to fall back if the muzzle is elevated. Very annoying. As for strength, it would seem it was perfectly suited for its day and was likely no weaker (perhaps much stronger) than a contemporary rolling block. The Trapdoor may have been a "stopgap" rifle but it was a pretty good one, and, I have come to believe, a better battle rifle than a rolling block if only for the extractor and camming action.

    Jerry Liles

  8. #8
    Boolit Master
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    Quote Originally Posted by 13Echo View Post
    The Trapdoor may have been a "stopgap" rifle but it was a pretty good one, and, I have come to believe, a better battle rifle than a rolling block if only for the extractor and camming action.

    Jerry Liles
    Jerry, I agree with most of what you wrote. I think the "stopgap" idea was good up to when they stopped using old parts and started making rifles from scratch, 1870 or so.

    As for the breechblock, I have taken to turning the trapdoor to the side when opening. It drops the empty in a pile (or my hand) and prevents the block from swinging back.

    I prefer the trapdoor to the other single shots of the day.
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  9. #9
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    Trapdoor carbine

    In the early 60s I bought a really nice carbine, about 95% at a gun show. I was able to chisel the guy down on the price as it had a broken extractor. He started at $50.00 and I was able to walk out with it for $35.00 along with a copious amount of ammo.
    The ammo was a mixed bag of about a hundred and fifty original mostly milsurp and a few marked WHV. I figured it was worth about a nickel each or less.
    After ordering an extractor from a place in West Hurley, New York and installing it I proceeded to shoot it. After shooting some of the copper cased ammo and breaking the new extractor, [copper cases stick] it found a new home as I considered it to be too unreliable to trust as a deer rifle. The military had to know. In those days nobody I knew thought of the trapdoor as being weak. I was a lot more recoil tolerant then.
    If I just had that bag of ammo now I could sell it for enough to buy the carbine at todays prices. Maybe?
    An other story has to do with a friend that told me the other day that his records show that I sold him a Sharps 45 70 Business rifle for $75.00 in that same period.
    Who knew?

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  10. #10
    Boolit Master
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    Quote Originally Posted by looseprojectile View Post
    In those days nobody I knew thought of the trapdoor as being weak.

    An other story has to do with a friend that told me the other day that his records show that I sold him a Sharps 45 70 Business rifle for $75.00 in that same period.
    Who knew?

    Life is good
    I started buying trapdoors in the 70s but remember the prices from the 60s and earlier. As I recall it was cheap but still a chunk of my weekly (weakly?) pay.

    You are right, in those days no one I knew considered the TD action to be weak. It was understood it was not a bolt action but also not weak. I wonder who/when that myth started?

    I have no plans to build one into a 300 Magnum but I have seen them in 30-30 and built one in 40-65. Maybe a 22 Hornet...
    Last edited by StrawHat; 12-29-2011 at 06:21 AM.
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  11. #11
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    Good morning
    Back to the order of strength... As we al know it is the weakest link that gives way. To me there is a BIG difference trying in short term to find destruction & the slow constant pounding a Breach system takes over thousands of rounds.
    The hinge pin sytem & the locking lever are the 2 items I look carefully at on each Trapdoor I handle. My last fear is a barrel or Breachblock coming apart. Imagine where that breachblock will go if the hinge pin lets loose. If the locking lever fails where is that cartrige & pressure headed ?
    I regularly shoot my 1868 caliber .50 when up here. I have never been concerned about the bursting ot the barrel or the fracturing of the breachblock... but I sure take a good look at that hinge pin area and locking lever.
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  12. #12
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    A Trapdoor can be fired without the hinge pin without disaster. The locking cam is another matter - it has to work or the breach will open as has happened with the H&R reproductions with the modified locking cam and lever.

    Jerry Liles

  13. #13
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    I kind of hate to get off the "trap door" subject, but needed some info. I have a handi rifle in 45-70 (why im posting here) and looking to get some pointers for reloading. While preparing to start load development (studying manuels) i disovered 3 different load datas according to lyman #49. one is for the 1873 springfield, 1886winchesrte/1895marlin, and ruger #1/#3 rifles (hotter). The Handi rifle is new and my first thought would be that the later would work. I am worried that at the low pressure that it operates that the case would not show signs of excessive pressure and the gun will fail. I like shooting the rifle and from my research the 45-70 is a round the can be improved (velocity) by reloading. All of the factory ammo I have seen seems to be loaded for the weaker style rifles.

  14. #14
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    Quote Originally Posted by emorris View Post
    I kind of hate to get off the "trap door" subject, but needed some info. I have a handi rifle in 45-70 (why im posting here) and looking to get some pointers for reloading. While preparing to start load development (studying manuels) i disovered 3 different load datas according to lyman #49. one is for the 1873 springfield, 1886winchesrte/1895marlin, and ruger #1/#3 rifles (hotter). The Handi rifle is new and my first thought would be that the later would work. I am worried that at the low pressure that it operates that the case would not show signs of excessive pressure and the gun will fail.
    You could have started your own thread, but since we are here...

    Start with the middle set of loads and work your way up. You may found what many Handi-Rifle owners have found, at a certain amount of recoil (not pressure per se) the rifle will become a self-ejector.

    That is, it will spring open immediately after firing. Not unsafe, but very disconcerting. Or, it may not! The difference seems to be some receivers are springier, or stretchier, than others.

    If it doesn't spring open itself, you may find yourself working right up into Ruger #1 territory. There, you will find the recoil to be terrific. Issues like rifle weight, balance, stock fit, stock shape, even the smoothness of the finish and the amount of stubble on your cheek suddenly become a factor in your recoil tolerance.

    Quote Originally Posted by emorris View Post
    I like shooting the rifle and from my research the 45-70 is a round the can be improved (velocity) by reloading. All of the factory ammo I have seen seems to be loaded for the weaker style rifles.
    Every cartridge can be improved by handloading, except the .338 Federal, which is factory loaded with magic faerie pixie dust gunpowder, which not only can not be duplicated by handloading, but crono and ruler owning handloaders shooting factory ammo. This cartridge is more powerful and flatter shooting than 7mm Rem Mag and .30-06 combined, all the gunwriters said so, all out of a case the size of the .308 and a bullet shorter in sectional density than, well, just about anything else.

    For that reason, I won't buy the .338 Federal, because I know I'll never match that kind of performance with my handloads. Or any other kind of loads, for that matter.

    -HF
    Last edited by HangFireW8; 02-19-2010 at 10:35 PM.

  15. #15
    Boolit Master
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    Let's see if this works.



    Good, a little blurry but readable. I will get the other article scanned in and on the thread when I get the chance. Some interesting experimenting done in the 60s!!
    Knowledge I take to my grave is wasted.

    I prefer to use cartridges born before I was.

    Success doesn't make me happy, being happy is what allows me to be successful.

    www.NoonSharpening.com

  16. #16
    Absolutely riveting info, gents. Many thanks.
    Have always suspected as much since the mid-late '80s, after casually blazing-away w/ a newly-acquired 1875 date specimen of long rifle. Still have her, too - but we've always kept the 405gr cast reloads quite light .......
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  17. #17
    Boolit Mold
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    Looks like this is an older discussion but sure am glad to find it.
    GREAT INFO!
    Just started loading and shooting the trapdoor. Have to admit... (even loaded around 1200 fps with 405 gn berry's hardcast, and 23 gn IMR 4198) the first 2 shots were fired tied to the old tire with a LONG string tied to the trigger!
    Call me a sissy if you must. But I believed the weak action stories too.
    Havn't increased the load so far. It's just plain fun to shoot!
    "I think that the world in which we shall live these next thirty years will be a pretty restless and tormented place; I do not think that there will be much of a compromise possible between being of it, and being not of it. -Robert Oppenheimer.

  18. #18
    Boolit Master
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    Not a thing wrong with soft loads. I stay strictly with black powder and lead boolits. But it is nice to know the is a bigger margin of safety than we may have been led to believe.
    Knowledge I take to my grave is wasted.

    I prefer to use cartridges born before I was.

    Success doesn't make me happy, being happy is what allows me to be successful.

    www.NoonSharpening.com

  19. #19
    Boolit Mold
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    I agree StrawHat- about the loads and the safety margin.
    I'm just getting set up to cast for the first time. The 45-70 will be my first boolit.
    A lee 405 gn hollow base. I've been told that is a difficult one to get to work for a beginner.
    Guess I will have to learn as I go like everyone did I'm sure.
    Looking forward to it.
    Did you know Winston Churchill is said to be the first person to fire an autoloader(a Mauser "broom handle") in combat?
    He also has a cigar size named after him. Gotta love it.
    "I think that the world in which we shall live these next thirty years will be a pretty restless and tormented place; I do not think that there will be much of a compromise possible between being of it, and being not of it. -Robert Oppenheimer.

  20. #20
    Boolit Master



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    I have an H &R Officer's trapdoor. Lately, the breech has been popping open on ignition. I've loaded my rounds to strictly "trapdoor acceptable" levels. Having it open is pretty disconcerting. I'd welcome any insights as to whether it is dangerous, can be fixed, or ignored.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check