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Repro Sharps gas leaks

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  • Repro Sharps gas leaks

    Hallo!

    I selfishly spent too much time sharing this not to try for double green stamps from it. :) :)

    Yeah, I know, a really dated cultural reference. ;)

    Hallo!

    I have never been a fan of the Italian "floating sleeve" check that due to QC issues often times does not float or work very well. But I understand the production savings which trickles down to cost savings to the customer.

    I did not check first, but "they" (Taylor's, Dixie) used to sell the tool that extracts the floating sleeve. IF it is not TOO far "off," it can be deburred, polished, and the chamber polished to enable it to function as well as the thing can function under the design and circumstances. But I would hate to recommend buying the thing and it does not solve the problem. Perhaps, some one you know or someone in your group or circles has one and you could get together.
    Anyways, if it does not move or "float" when the pressure in the chamber needs to push it back against the solid breech block face, it will leak. They also leak over time as the sleeve starts to form an impact/wear ring on the breech block face.

    Again, the gun is not here for me to examine and see.. but I will venture a guess that you may have a recent enough repro Sharps that it has a Sharps gas check- BUT I am puzzled as I do not recall the Italians making a Sharps gas cheeck breech when they use the floating sleeve check in the chamber? (Because they simplified production by simply casting what would have been the detachable/removeable check plate to be part of the breech block).

    But Pedersoli has tried three (four?) versions/variations in the past few years trying to get sometmhing that works and holds up (a larger factor with
    N-SSA skirmishers versus reenactors who NUG fire less rounds AND do not generate breech pressures NUG sufficient to get the sleeve to move backwards and tightly butt against the breech block face!))

    Original Sharps do have a "sleeved chamber" that was adjustable by an armorer to compensate for the floating breech plate wearing. It was discovered with the pre 1859 tailed cartridge that loose power grains debris worked its way between the gas check plate and the breech block face.

    One originals and Shiloh reproductions of originals, the gas seal plate moves forward to seal against the breech by a "pressure differential." At the rear of the gas check plate, an extension fits tightly into a recess made into the block. The extension tapers down towards the rear to somewaht of knife edge. When the round is fired, the gases expand into the recess, applying pressure on the taper. Because the taper is angled slightly , pressure is applied BOTH forward and outward. The breech block moves forward because the recessed area is ever so larger in diameter than the chamber. The pressure from the round is equal in the chamber and breech block area. (The Italian version is straight, it does not taper which reduces its effectiveness.)
    But the larger cavity behind the gas plate creates more surface area for the tons or pounds per square inch to push on. There is greater pressure on the back of the gas plate than on the front. As a result, the gas check/seal moves forward.
    Also, The "quillotine" or knife edge at the back of the taper also moves to form a tight seal against the sides of the breech block recess, adding to the seal.

    Sharps found out that the grit and debris from the powder spilled when the tail of the pre 1859 cartridges got between the block and the gas check/seal plate causing it to become loose. So, just before the War, they redesigned the cartridge to not have a tail and that did not require the breech block top to cut through the cartridge any more.

    IF you have a true Sharps type removable plate, there are two recess in its side for a small screw driver to pop it out from its snug fit. If it is the molded solid version there is no plate to pop off/out.

    "O" ring modification...

    Hmmmm. With the full caveat that I am describing the modifcation perhaps best done by a gunsmith, a machinist, or a lad with machinist skills and tools... and NOT necssarily as a "How To Ruin Your Sharps."

    In increasing order of complexity...

    1. .875 diameter "O" ring about .125 thick. Square sided are better, round will work. You take out the pressure plate and insert the "O" ring at the bottom of the recess, then put the plate back in. The breech will operate TIGHTLY, but will eventually get loose as the "O" ring gets worn out, and succumbs to the heat and dries out. So, some lads replace them before and after every event.

    2. Since the "O" ring takes up space.... some lads mill the back of the recess down a tad- the bottom of the recess needs to be .015 less than the diameter of the "O" Ring and the space between the pressure plate and the breech face. A "feeler gauge' is needed).)
    This prevents the really tight working of the loading lever when it closes and compresses down the
    new(er) "O" ring.

    3. Coin method. I got decent improvement with one of my Sile Sharps by smoothing off a Quarter, drilling a hole in its center for the "flash director" cone in the breechblock, and just friction fit tapping it down to the rear of the recess. That put added space for the floating plate to push back against and eliminated gassing. But it required a machinist making several spare plates as the knife edge had to taken down a few thousands of an inch due to the width of the dime.

    4. I won't get into this as it is much more radical. Some lads fit a shaped steel plate over the breech block. Then modify the rear of the chamber to hold two removable, floating ring-like gas checks separated by an "O" ring. When a charge is fired, the gas pressure moving in all directions, pushes back towards the rear. It then pushes the metal double ring/"O" ring sandwich gas seal backwards against the now solid breech block face, making the gas seal. (AS the "O" ring wears out and dries out from use and heat, it too needs replaced.



    And as with the Italian floating sleeve check, it does require cosntant cleaning and maintenance.

    Sorry, I had a bunch of Sharps images but they are trapped in a dead hard drive, so these will have to do:










    Last but not least....

    IMHO, Sharps were not designed to fire blanks. By and large, and for the most part, both the originals and the Italian repro's gas checks systems work less-than-best when a bullet is "sealing" the chamber and exerts significant rearwards pressure. Unforuntately not so much with a blank charge's reduced pressures.

    Curt
    Last edited by Curt Schmidt; 05-01-2012, 01:31 PM.
    Curt Schmidt
    In gleichem Schritt und Tritt, Curt Schmidt

    -Hard and sharp as flint...secret, and self-contained, and solitary as an oyster.
    -Haplogroup R1b M343 (Subclade R1b1a2 M269)
    -Pointless Folksy Wisdom Mess, Oblio Lodge #1
    -Vastly Ignorant
    -Often incorrect, technically, historically, factually.

  • #2
    Re: Repro Sharps gas leaks

    I've found that the DGW chamber sleeve tool works if the sleeve hasn't been frozen long -- a few days perhaps. For those that have been frozen in place for some time, there's another approach that's not too expensive and doesn't involve any engineering. Here's how a member of my home unit explained it in an e=mail to the group:

    "I found the perfect tool to break the sleeve loose. It's an automotive
    valve lifter puller (Lisle 13750). Unlike the brass tool you can buy
    from your local sutler, it doesn't use friction to grab onto the
    sleeve. Instead it grabs onto the innermost edge of the sleeve.
    There's actually a gap in there between it and where the rifling begins.

    "Once the tool is properly in position, it has a sliding chunk of brass
    (a slide hammer, actually) that you run up the tool away from the
    chamber until it smacks into the handle. After a half dozen hits, the
    chamber reluctantly starts moving, at which point you can pull it out as
    far as it will go and clean all the carbon fouling out.

    "It moves nice and easy now!

    "The tool is about $30 retail - but I happened to have one from when I
    rebuilt my old Buick.

    "Here's one on Amazon:

    "http://www.amazon.com/Lisle-13750-Hydraulic-Lifter-Puller/dp/B000P0VT8C"

    For hard cases some application of heat may be necessary, but the author of the note managed to free up the sleeves on two of our Sharps that had been locked up for years.
    Michael A. Schaffner

    Comment


    • #3
      Re: Repro Sharps gas leaks

      Having the same issues, I am very interested in the fix. Tom, let me know how it works out. I just got my Sharps back from gunsmith replacing spring and centering hammer over cone. Only advantage of misfires was less burns around hands!

      Comment


      • #4
        Re: Repro Sharps gas leaks

        Hallo!

        I have read material that says that the Italian Sharps Rifles have floating sleeves that can be removed. But the "Berdan Contract" version does not.
        And, that the Italian Sharps Carbine sleeve cannot be fully removed.

        In doing some archival searches, I found a reply from Pedersoli in 1999 that says that their owner's manual was mistranslated to say "remove" the sleeve when it should have said "move" the sleeve.
        And that it cannot be fully removed as it butts agains the receiver.

        I wish I could be of greater help, but none of the Italian companies send me a sample when they make changes and fiddle with production- so with several companies each with several changes.. I cannot keep up. ;) :(

        I read this morning that Pedersoli did away with the floating sleeve, and went to a more "Sharps" design, but by not using a tapered gas check/seal plate, they use three "O" rings in the recess to compensate. I have not had the chance to handle or view any with this change that is suposed to be a couple or three years old now.

        In any event, if one has a floating gas check sleeve that does not "float" it will leak gas.

        If it is frozen to the rear, it will work until it wears on the breech block face and gas escapes.

        Curt
        Last edited by Curt Schmidt; 05-02-2012, 03:45 PM.
        Curt Schmidt
        In gleichem Schritt und Tritt, Curt Schmidt

        -Hard and sharp as flint...secret, and self-contained, and solitary as an oyster.
        -Haplogroup R1b M343 (Subclade R1b1a2 M269)
        -Pointless Folksy Wisdom Mess, Oblio Lodge #1
        -Vastly Ignorant
        -Often incorrect, technically, historically, factually.

        Comment


        • #5
          Re: Repro Sharps gas leaks

          This past winter I sent my well-worn 1864 manufacture NM1863 Sharps carbine off to Charlie Hahn for one of the variations of his Sharps breech job. Inexpensive and quick turn around. I've played with this piece for 50 years. It spit hot gas like a Durham bull's butt and seized up after twelve or fifteen shots. Now I can run forty rounds through it and the action works as well at the end as at the beginning. And, wonder of wonders, it's as gas tight as my Maynard, my Burnside, and tighter than my Spencer, a joy to shoot! A put-together NM1863 rifle, manufactured in 1865, followed, with the same happy results. Charlie works on all the replica Italian variations, does a deal of work for the N-SSA fellows, provides cardboard cartridge tubes fitted to ringtail bullets, and can be reached at etb9601@aol.com .
          Last edited by David Fox; 05-03-2012, 04:43 AM.
          David Fox

          Comment


          • #6
            Re: Repro Sharps gas leaks

            Guys,
            Thanks for the great advice and input! Curt, I replied in more detail on the other forum.

            David, as someone who isn't mechanically inclined, this sounds like a great resource. Thanks for posting!

            Take care,
            Tom Craig
            1st Maine Cavalry
            Tom Craig

            Comment


            • #7
              Re: Repro Sharps gas leaks

              Years ago when live firing my Sharps, I came up with an expensive, easy and fast fix for the leaking gas block. All that is needed is a screw driver, some emory cloth, a sharp knife and a few toilet tank washers.
              First, remove the gas plate from the breech block. Polish the mating surfaces with the emory until when turned upside and gently shaken the gas check plate slips out of the block. Slice a toilet tank washer in two like you would slice a bagel and place one half of the washer behind the gas plate then reinsert the block into the receiver. Voila a metal to metal seal. When live firing, after about 40 rounds the washer would get brittle from the heat and crack/break. A bit of water makes everything soft enough to change get the plate out of the block and replace washer. Never tried it with blanks though.

              Dave Myrick

              Comment

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