Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Huge barrel to cylinder gap on a new 1858 Pietta

Discussion in 'Blackpowder' started by Mizar, Dec 18, 2010.

Thread Status:
Not open for further replies.
  1. Mizar

    Mizar Member

    Joined:
    Mar 23, 2004
    Messages:
    658
    Location:
    Sofia, Bulgaria
    Hello. Recently I bought a nice 5 1/2" Pietta 1858 New Model Army from Cabela's. I have not shoot it yet - mainly because I do not have time. So, the barrel to cylinder gap measures 0.02" (0.5 mm). What can I expect from this excessive gap in terms of velocity loss, lead spitting, fouling and etc? Me and a friend of mine bought two 5 1/2" Piettas and both have the same gap. The revolvers have no other problems - timing is excellent, the inside and outside are finished very well - the revolvers needed just minor adjusting and polishing of the internals (bolt, hand and hammer). I do not want to return it to Cabela's - except for the gap the revolver is mechanically flawless.
    The real question is - can I live with such a huge B/C gap or should I unscrew the barrel and adjust it?

    Thank you in advance,
    Boris

    P.S. I am new to the world of Black Powder shooting so do expect lots and stupid questions in the near future...;)
     
    Last edited: Dec 18, 2010
  2. mykeal

    mykeal Member

    Joined:
    Sep 9, 2006
    Messages:
    5,147
    Location:
    Michigan
    Not sure if you have a problem or not. 0.2 inches is 5 mm, not 0.5 mm. Your barrel to cylinder gap is either 0.02 inches (0.5mm) or 0.20 inches (5.0 mm). If the former you have no problem; if the latter there is something seriously wrong with the gun and it should be returned to Pietta.
     
  3. arcticap

    arcticap Member

    Joined:
    Mar 20, 2005
    Messages:
    6,185
    Location:
    Central Connecticut
    Since there's 2 identical guns, I'll wager that it's only a misplaced decimal point and not a gross defect. :)
     
  4. madcratebuilder

    madcratebuilder Member

    Joined:
    Jul 15, 2007
    Messages:
    5,020
    Location:
    Northern Orygun
    A barrel gap of .020 inch is twice what I would expect. A new BP revolver should be around .006-.008.
     
  5. Mizar

    Mizar Member

    Joined:
    Mar 23, 2004
    Messages:
    658
    Location:
    Sofia, Bulgaria
    mykeal and arcticap, my bad - 0.02 inches - I am in the metric part of the world and confused mm with cm for the conversion :eek: the gap is 0,5 mm - measured with a feeler gauge. Like I said - this is my first C & B revolver and compared to modern revolver the gap seems excessive. Thank you both for the answers!

    Boris

    P.S. I am going to edit my post because of the embarrassment...
     
  6. junkman_01

    junkman_01 member

    Joined:
    Aug 7, 2009
    Messages:
    1,728
    Location:
    Florida
    Now that you have the barrel gap dimension cleared up, leave it alone. First off, if you were to screw in the barrel a turn, it would create a problem latching the loading lever. Secondly, the cylinder on BP revolvers slides forward and closes the gap because of the hand spring before the firing. A gap is necessary so the cylinder face doesn't jam on the back of the barrel due to the black powder fouling and make the gun almost impossible to re-cock. Just make sure that the hammer can still fire a cap when the cylinder is in it's forward most position.
     
  7. Mizar

    Mizar Member

    Joined:
    Mar 23, 2004
    Messages:
    658
    Location:
    Sofia, Bulgaria
    junkman_01, that is not an answer to my question.
    1. If I face the front portion of the frame and screw the barrel one full turn there will be no real problem with the loading lever - if there is some interference with the latch the problem will be solved with 10 minutes work with a file followed with a cold blue.
    2. The endshake of the cylinder is almost non existent - it will put a Colt to shame. If your revolvers have so much endshake as you described I suggest a visit to some gunsmith for correction.

    Best,
    Boris
     
  8. J-Bar

    J-Bar Member

    Joined:
    Nov 24, 2010
    Messages:
    2,472
    Location:
    Springfield, MO
    On an open-top Colt style revolver, when you cock the hammer, the pressure from the hand pushes the cylinder forward a bit, so the gap is narrowed when the gun is fired. I don't own a Remmie 58, so I can't check to see if they do the same thing, but I'm curious...does the gap narrow any when you cock the gun?
     
  9. Mizar

    Mizar Member

    Joined:
    Mar 23, 2004
    Messages:
    658
    Location:
    Sofia, Bulgaria
    When the gun is fired the recoil forces are pushing the cylinder back and the gap is at its biggest measure again. Like I said - The endshake of my revolver is almost non existent - it will put an (old) Colt to shame.

    Boris
     
  10. mykeal

    mykeal Member

    Joined:
    Sep 9, 2006
    Messages:
    5,147
    Location:
    Michigan
    I'm with madcratebuilder -0.02" is twice what I want in my revolvers, but it's a whole lot better than 0.20"!

    As far as 'repairing' the problem, that depends entirely on what's causing it. Is it a tolerance stackup (all parts are dimensionally in tolerance but near the limit such that the sum exceeds whats acceptable), or is it due to one part being out of tolerance? Fixing the assembly to correct one part being out of spec is generally not a good solution. Unfortunately it's difficult to make that determination without a good example to compare it with.

    The lack of significant endshake makes me think the problem is with the barrel - the cylinder fits with the frame and arbor assembly. That suggests turning the barrel might work. However, I'm not at all sure there is enough thread length to support a full turn of the barrel. If there is, it was just installed incorrectly, which isn't all that hard to imagine. But if the barrel is installed properly, and there isn't enough thread left to turn it down, then the problem is an out of spec part, and the solution is to replace it.
     
  11. junkman_01

    junkman_01 member

    Joined:
    Aug 7, 2009
    Messages:
    1,728
    Location:
    Florida
    On my Remmie the gap closes when cocked.
     
  12. flibuste

    flibuste Member

    Joined:
    Mar 20, 2007
    Messages:
    231
    Location:
    Near PARIS in FRANCE
    Hello,

    I bought once a 1858 Pietta with a 0.5mm gap as yours ; although I could have done with it, I sent it back for a replacement : the one I received in return had a very tight gap but chambers / barrel alignment was not perfect ......... However I kept this one.

    - As for the 0.5mm gap it is not optimum but managable

    - As for turning the barrel, you will have to turn it one full turn and then grind the face of the barrel facing the cylinder ; however in my experience, there is a gorilla in Pietta workshop who is in charge of screwing these barrels and you may face great difficulties when unscrewing it.........

    good luck
     
  13. Mizar

    Mizar Member

    Joined:
    Mar 23, 2004
    Messages:
    658
    Location:
    Sofia, Bulgaria
    mykeal and flibuste, the barrel's thread length is out of spec and it can't be screwed further that this. I can correct the problem in two ways:
    First way (which I prefer) - remove barrel, grind the front of the frame with a mill the desired length needed for one full turn, adjust overall barrel length and forcing cone on a lathe (good enough for this revolver).
    Second way - grind the barrel in front of the threads on a lathe to the desired length needed for one full turn. Everything else - like the first method.

    But the real question is - is it worthed? If you have a revolver with similar B/C gap how it is performing - do you notice considerable velocity drop, excessive fouling and leading, bad accuracy?

    Boris
     
  14. BHP FAN

    BHP FAN Member

    Joined:
    Sep 23, 2008
    Messages:
    5,810
    Location:
    Northern California
    That's actually pretty standard, and won't hurt anything.I've had repros from the '70's that had gaps as much as a 1/32'' on one opentop, and it worked just fine.
     
  15. GCBurner

    GCBurner Member

    Joined:
    Nov 18, 2010
    Messages:
    1,853
    If the gap is TOO tight, fouling will make the cylinder bind up after ten or twelve rounds. I'd leave it alone, if it were mine.
     
  16. junkman_01

    junkman_01 member

    Joined:
    Aug 7, 2009
    Messages:
    1,728
    Location:
    Florida
    I told him all that in post#6. He just won't listen.:banghead:
     
  17. Mizar

    Mizar Member

    Joined:
    Mar 23, 2004
    Messages:
    658
    Location:
    Sofia, Bulgaria
    And I did reply to you, junkman, in post #7... Do you really get the difference between NO gap at all, a 0.005 - 0.006" gap (which is more or less standard these days) and a 0.02" gap?

    Boris
     
  18. junkman_01

    junkman_01 member

    Joined:
    Aug 7, 2009
    Messages:
    1,728
    Location:
    Florida
    Boris,
    YOU are not getting it. Just leave it alone and shoot it. You will be making more trouble for yourself if you start messing around with it, because I fear you do not understand how the C&B revolver is supposed to work. You continue to compare it to a modern revolver, which it is not.
     
  19. TheRodDoc

    TheRodDoc Member

    Joined:
    Feb 4, 2010
    Messages:
    385
    Location:
    Iowa
    That is a very large gap.

    using .454" dia. and .020, that gives a cyl. wall area of 0.028526 sq. in. area in the gap.

    a circle .190" in dia. has about the same area.

    that would be about like drilling a no. 11 sized hole in a rifle barrel just over the loaded ball.
    .034 bigger then a 3/16" hole. no 11 bit (.191)

    that's a big leak.

    I read an article on the web where they reset the gap on a SAA from .006" to .002" and the chrony results gained 100 fps muzzle velocity.

    and this guy gained 100 fps per .001" that the gap closed in tests with a 357.
    So even though were talking BP revolvers here the velocity loss could be a fair amount.

    http://fiveshot.org/backissues/paco/velocity.htm
     
    Last edited: Dec 18, 2010
  20. Mizar

    Mizar Member

    Joined:
    Mar 23, 2004
    Messages:
    658
    Location:
    Sofia, Bulgaria
    Junkman, I am getting a little tired from this. I did not ask what you consider to be optimal or to give me an advise not to do it. I did ask a specific question and you did not answer it. From my searching the "standard", common, B/C gap on a new Pietta NMA is between 0.005 and 0.007" and quite a few people are living happy with it. I am not asking you for opinion on my machining and gunsmithing skills so, please, keep it to yourself.

    Best,
    Boris
     
  21. junkman_01

    junkman_01 member

    Joined:
    Aug 7, 2009
    Messages:
    1,728
    Location:
    Florida
    This what you asked in your first post and I tried to help you and answered your question. Leave it alone and just shoot it.
     
  22. rdstrain49

    rdstrain49 Member

    Joined:
    Dec 3, 2010
    Messages:
    343
    Location:
    South Dakota / Black Hills
    You can return your Rem. to Cabellas even if it has been fired, but not if it has been modified. Just shoot it. If it does not meet your expectations just send it back. Piettas are not perfect, but for the price they aren't bad. I have issues with barrel not being indexed properly on my Pietta Army, but considering the groups it will shoot, I can live with it. Enjoy, don't worry:)
     
  23. junkman_01

    junkman_01 member

    Joined:
    Aug 7, 2009
    Messages:
    1,728
    Location:
    Florida
    I just measured the barrel to cylinder gap on my own '58 Remington (made by PR, brass frame) and it measures .016 inches. It shoots just fine thank you.
     
  24. Bluehawk

    Bluehawk Member

    Joined:
    May 28, 2006
    Messages:
    1,043
    Wow...and all this time I thought the gaps on mine, .006 and .007...were excessive!
    Mizar...Junkman is trying to help you by getting you to use some common sense in that shooting the gun first is the smartest action to take. After that, if you are not satisfied with it's performance, then you can either modify it as you wish (it's your gun) or return it to the place of purchase. Myself, I would return it with a gap that large!
    Getting defensive or arrogant with others trying to help you isn't going to get you much advice in the future so you might want to relax a little bit.
     
  25. ak-kev

    ak-kev Member

    Joined:
    Sep 6, 2007
    Messages:
    408
    Location:
    Lakeland, Florida
    Wow junkman, its seems conflict and strife follow you around. Two threads in as many days. I used to respect your posts, but I may need to re-think this.
     
Thread Status:
Not open for further replies.

Share This Page