Colt M1878 cylinder spins backwards

Snagglepuss

August 12, 2003 14:32

I've got a Colt 1878 DA "1902 Alaskan/Philippine" revolver. When releasing the trigger and manually seating the hammer, so as not to dry fire, the cylinder spins backwards a bit. It does not do this if the chambers are loaded (with just empty brass). Is this a common Colt M1878 problem? Thanks.

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  kingjoey

  August 12, 2003 15:13

  Might check the cylinder catch to see if it is worn, sometimes when the catch is worn/stuck the hand retracting across the ratchet can pull the cylinder back a little. Probably wouldn't hurt to give the gun a good cleaning too, might have crud behind the ratchet hand forcing the hand into contact with the ratchet going both ways.
  
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  punchie

  August 13, 2003 05:38

  Mine doesn't. Don't know if it is normal or not. I do know the lockwork is very fragile and parts are getting harder to come by to repair.
  
  AN ARMED SOCIETY IS A POLITE SOCIETY

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  Snagglepuss

  August 13, 2003 10:54

  I read the other day in someone's GunBroker listing of a 1902 Alaskan whose pistol suffered the same problem of cylinder rotation but can't find the listing now. Which prompted me to think this might be a problem among m1878's.
  
  I removed the cylinder and inspection hatch, all looks good (and appears clean from what I can see). Cylinder catch seems to have a lot of spring to it. (Maybe too much as it might spring out the ratchet and catch the cylinder both ways as you pointed out.

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  bobski

  August 13, 2003 13:59

  dont they call that thingy that catches the cylinder the 'hand?' i cant remember.
  
  former air operations officer SEAL Delivery Vehicle Team 2. former navy skeet team, navy rifle/pistol team member. co-owner skeetmaster tubes inc.. owner/operator professional shooting instruction.

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  v35

  August 13, 2003 15:38

  If the cylinder has too much fore and aft play, the cylinder locking bolt will slip out of the cylinder notch, allowing the hand to drive the cylinder in reverse when you release the hammer.
  With the cylinder removed, the bolt should retract momentarily as the hammer is cocked. When you release the hammer by pulling the trigger
  the bolt should not move. Does it?

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  Snagglepuss

  August 14, 2003 06:10

  I removed the cylinder and cocked the trigger, the bolt moved up, when I pulled the trigger the bolt did not move as long as I did not release the trigger, once I released the trigger the bolt moved back down to it's lowest position. It must be cylinder play as you point out. If I apply a small amount of pressure to the front of the cylinder all works well!
  
  I just found an online schematic of the M1878 (should have thought of this earlier) and the part I keep referring to as cylinder catch and/or bolt is listed as "Hand Machine"
  
  How is the cylinder bushing held in the cylinder? By pressure? Friction? Weld?

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  v35

  August 14, 2003 07:55

  I think the 1878 takes the SAA cylinder bushing. Tou could fit a new one or shim the old one to take out the fore and aft play.

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  v35

  August 14, 2003 08:33

  Unfortunately, I'm not familiar with the 1878. On some old revolvers without rebounding hammers, the firing pin sticks in the indentation of a fired primer & keeps the cylinder in place to prevent the cylinder from turning while the trigger goes forward and the hand retracts to pick up another cog on the ratchet. This may be so on the 1878 because the bolt should normally drop down and unlock the cylinder only as the hammer is being cocked.

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  Snagglepuss

  August 14, 2003 14:48

  It looks like it takes a special tool to pull the cylinder bushing from the cylinder so I don't think I'll try. I got out my feelers gauge and slid a shim (.006) in-between the front cylinder gap and it seems to correct the problem.

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  wacowt

  August 17, 2003 12:11

  The cylinder on this model doesn't have locking bolt notches and no locking bolt as described in William Mason's patent description. The loading gate has a "tooth" and is spring loaded causing it to apply pressure between the ratchetts at the rear of the cylinder. This was supposed the hold the cylinder in place while the hand was retracted below and catching the next ratchett. This was the only provision to prevent the cylinder from turning backwards.
  If you half cock the hammer and turn the cylinder, you should notice the loading gate moving in and out on it's axis. Yep, mine doesn't work either.

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