Author Topic: Excessive CB Gap, need professional opinion.  (Read 1117 times)

Offline RUSS123

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Re: Excessive CB Gap, need professional opinion.
« Reply #20 on: February 11, 2020, 06:41:33 PM »
That's great Russ!
  The Open Top is the design of the percussion revolvers Colt made. The top strap design is what the Root revolver was as well as the 73 Peace Maker and all the other Colt revolvers made since.
  The '71 Open Top is Colt's first cartridge offering. So it's the " '71"  part that designates that particular open top  as the cartridge one. All the others were percussion revolvers.

Mike

Thanks Mike,

Conversions are just modified original percussions, retrofitted as a breech loaders to use cartridges and included a gate.

Being that mine is Colt's first purposely made cartridge revolver of the OT design, is it more correct to call it the 71 or 1871?
Russ

Pietta Frontier 7.5 357mag
Uberti 1872 OT 7.5 38 Sp.
Ruger Blackhawk Hunter 44mag
Ruger Single Six Hunter 7.5 22mag Conv.
Ruger Vaquero New 5.5 357mag

Offline Coffinmaker

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Re: Excessive CB Gap, need professional opinion.
« Reply #21 on: February 12, 2020, 10:56:58 AM »

Hi Russ.

I'm not Mike.  I'm the "other Mike."  Perhaps some miss-understanding and/or disagreement.  First though, the designation "71/72" refers to the years the Open Top were manufactured.  Colts first purpose built Cartridge guns.  Percussion guns don't have head space.  Leave it at that or you'll need some Aleve (washed down with Ale).

ALL Colt pattern Percussion Guns are Open Top.  No top strap.  The Open Top is an open top.  No top strap.  Colt called Remington and their own 1873 "Strap Guns" in house.

The 1871/1872 Open Top is a new deal.  The Gas Ring can and does and was intended to maintain Head Space for cartridges.  If the users manual says to back off the wedge if the gas ring binds, is a "cop out" to allow for an abysmal Barrel to Arbor fit.  If Sam'l picked up a Uberti Open Top (any style) he'd have apoplexy.  That fit SUCKS!!  So here is the bottom line according to ME.

BEFORE anyone does anything else to a Uberti built Open Top type gun, the Barrel to Arbor fit ABSOLUTELY MUST be corrected.  One should be able to shove the wedge in with a sledge hammer and not affect the Barrel to cylinder gap nor bind the gas ring.  PERIOD.  Fooling with the wedge seating is just plain silly.  Once the Barrel to Cylinder fit is corrected, and only then, can the wedge be correctly fitted.  the wedge should fit with only thumb pressure or a light tap from the butt of a screwdriver.

Now, let's really confuse ya.  Conversion guns of the Colt Pattern, with a Gated Ring for Suppositories have End Shake.  Sort of.  Maybe.  Not really.  The head spacing is achieved by controlling the Barrel to Cylinder gap.  Barrel to Cylinder gap should not exceed .006 with cartridges in the gun (use dummies to measure).  This allows the firing pin to reach the primer.  You CANNOT achieve correct, consistent B/C gap without first correcting Barrel to Arbor fit.  You will notice a pattern here.  The pattern hold true for ANY Colt pattern Open Top Design.  Before anything else is done, one must ABSOLUTELY FIRST correct the Barrel to Arbor fit.  Otherwise Barrel to cylinder gap and for Suppository shooters, the Head Space WILL wander all over the place.

Coffinmaker
(The Other Mike)

By the way.  The Other Other Mike and I both achieve the same results.  Differently.  We just sometimes disagree on how to get there.  End result is a Dead Reliable gun.

Offline RUSS123

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Re: Excessive CB Gap, need professional opinion.
« Reply #22 on: February 12, 2020, 05:19:00 PM »
Hi Russ.

I'm not Mike.  I'm the "other Mike."  Perhaps some miss-understanding and/or disagreement.  First though, the designation "71/72" refers to the years the Open Top were manufactured.  Colts first purpose built Cartridge guns.  Percussion guns don't have head space.  Leave it at that or you'll need some Aleve (washed down with Ale).

ALL Colt pattern Percussion Guns are Open Top.  No top strap.  The Open Top is an open top.  No top strap.  Colt called Remington and their own 1873 "Strap Guns" in house.

The 1871/1872 Open Top is a new deal.  The Gas Ring can and does and was intended to maintain Head Space for cartridges.  If the users manual says to back off the wedge if the gas ring binds, is a "cop out" to allow for an abysmal Barrel to Arbor fit.  If Sam'l picked up a Uberti Open Top (any style) he'd have apoplexy.  That fit SUCKS!!  So here is the bottom line according to ME.

BEFORE anyone does anything else to a Uberti built Open Top type gun, the Barrel to Arbor fit ABSOLUTELY MUST be corrected.  One should be able to shove the wedge in with a sledge hammer and not affect the Barrel to cylinder gap nor bind the gas ring.  PERIOD.  Fooling with the wedge seating is just plain silly.  Once the Barrel to Cylinder fit is corrected, and only then, can the wedge be correctly fitted.  the wedge should fit with only thumb pressure or a light tap from the butt of a screwdriver.

Now, let's really confuse ya.  Conversion guns of the Colt Pattern, with a Gated Ring for Suppositories have End Shake.  Sort of.  Maybe.  Not really.  The head spacing is achieved by controlling the Barrel to Cylinder gap.  Barrel to Cylinder gap should not exceed .006 with cartridges in the gun (use dummies to measure).  This allows the firing pin to reach the primer.  You CANNOT achieve correct, consistent B/C gap without first correcting Barrel to Arbor fit.  You will notice a pattern here.  The pattern hold true for ANY Colt pattern Open Top Design.  Before anything else is done, one must ABSOLUTELY FIRST correct the Barrel to Arbor fit.  Otherwise Barrel to cylinder gap and for Suppository shooters, the Head Space WILL wander all over the place.

Coffinmaker
(The Other Mike)

By the way.  The Other Other Mike and I both achieve the same results.  Differently.  We just sometimes disagree on how to get there.  End result is a Dead Reliable gun.

Hello Coffinmaker Mike!

BTW, I did know your name was Mike also....:)

I spoke with Dragon Mike over the phone last night about what all he'll need to do to correct mine. I'm going with his full tuning package. Everything you've just said I've become so familiar with now, especially the Arbor fit. I'm mechanically savvy enough to understand what's going on here. So yes, I see that, just as you say: "You CANNOT achieve correct, consistent B/C gap without first correcting Barrel to Arbor fit" Consistency in the Head Space as well, which I'm sure you'll agree is most important.

The Gap, Endshake and head space will all vary together based on how far the wedge gets pressed or slammed into an Arbor too short to make solid contact with the barrel. It's FLOATING.  It's not the job of the wedge to set these spaces. It's the Arbor's job to establish a space consistency by its fit with the barrel. The wedge is there only to firmly hold the two, barrel - Arbor, solidly together with just a light tap. Mine felt like it was inserted by an Arbor Press.

I actually began learning about the ill faded Arbor fit before I took possession, information which came mostly from You and Dragon Mike so I was prepared in what I might find. When I finally got it home I took it apart to perform the arbor check and realized the error for myself. I wasn't surprised nor was I disappointed, reading that they all come like this.

I had two choices: Send it back to Cimarron or ship it off to Mike. I wasn't sure of what I'd be getting back from Cimarron but I knew what I'd be getting back from Mike so I made the decision, forget the warranty! After all, I'd be sending it to Mike anyway.

Coffinmaker: "BEFORE anyone does anything else to a Uberti built Open Top type gun, the Barrel to Arbor fit ABSOLUTELY MUST be corrected".  In the future, I'll be marching to that same drumbeat myself along with the two of you.
Russ

Pietta Frontier 7.5 357mag
Uberti 1872 OT 7.5 38 Sp.
Ruger Blackhawk Hunter 44mag
Ruger Single Six Hunter 7.5 22mag Conv.
Ruger Vaquero New 5.5 357mag

 

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