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Cas City Forum Hall & CAS-L  |  CAS TOPICS  |  Gunsmithing  |  Topic: Open top Uberti revolver issues 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: Open top Uberti revolver issues  (Read 2742 times)
Gabriel Law
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« on: July 17, 2016, 09:35:40 pm »


I have an open top .38 spl revolver in the shop right now, that has a couple of issues.  The first is that primers don't go off every time, or so the owner says.  I myself have not tried live ammo - just primed cases.  And he is right.  So we concluded that the firing pin is not hitting the primer hard enough and may not be coming through it's hole in the frame far enough.  I looked after those two issues by removing metal from the hammer to make the pin stick out a little further, and added a leaf of hacksaw blade under the mainspring to beef it up.  The hammer falls with a good fast snap, but still, the primer is not always ignited.
Second, when a primer does fire, the primer backs out of it's pocket and jams the cylinder.  Would this happen with live ammo?

Can anyone offer any suggestions on why, and a remedy, please?
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Reverend P. Babcock Chase
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« Reply #1 on: July 17, 2016, 09:56:07 pm »

Howdy GL,

Did you check the headspace? The backed out primer may mean that the case is sitting too far into the chamber, but I don't understand all I know about these things.

Reverend Chase
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Gabriel Law
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« Reply #2 on: July 17, 2016, 10:17:43 pm »

This revolver does not have a rebated chamber...the cartridge rim sits flush with the rear face of the cylinder.  With a live cartridge in the chamber, the hammer does not go all the way down to bed against the frame...the pin rests against the primer.  So pin length is not an issue, m'thinks.
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Pettifogger
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« Reply #3 on: July 17, 2016, 10:27:35 pm »

It is normal for a case with a primer only to jam the cylinder.  With live ammo pressure forces the case back against the recoil and reseats the primer.  There are several things that could be causing your problem.  Ubertis have universally poor fitting arbors.  Have you checked the barrel/arbor fit?  This can affect endshake and cause problems.  If you have an 1872 Open Top as opposed to a conversion have you checked the Mickey Mouse safety that is built into the hammer?
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Gabriel Law
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« Reply #4 on: July 17, 2016, 10:56:49 pm »

Thanks so much for your reply Pettifogger.  What should I be looking for in the barrel/arbor fit?  I have a number of Uberti revolvers and should be on top of that, if you can assist.  Thanks for the tip on using live ammo and primer stuff.

The hammer safety is quite a contraption...it is currently set to 'fire'.
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Pettifogger
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« Reply #5 on: July 18, 2016, 10:26:59 am »

These might help.

http://www.theopenrange.net/forum/index.php?topic=7988.0
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Coffinmaker
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« Reply #6 on: July 18, 2016, 12:35:22 pm »

Yep.  First and foremost, you need to go read ALL of the tutorials provided by the Esteemed Pettifogger.

Pettifogger and I have frequently addressed Uberti Open Top design guns as "KITS."  FINE looking KITS.  Some (lots) finish work
required.  You CANNOT resolve the issue(s) you describe by addressing one or two items.  You'll be chasing your tail.  First of all,
removing metal from the hammer is a mistake.  Adding a piece of hacksaw blade under the Main Spring is a mistake.  In the
direction your going, your mistakes are going to get expensive.

You cannot address ANY problem with an Open Top until you address the Barrel to Arbor fit and insure correct Head Space and End Shake.
Until you have done that, anything you do is a waste of time, effort, and money in replacement parts.  If the gun came to you with an
OEM Main Spring, it was already TOO heavy.  Trying to make it heavier is just causing damage to the gun.

Primers backing out of an empty case is NORMAL.  It will happen every time.  The primer backs out of EVERY case when fired.  A live round recoils back against the recoil shield and reseats the primer.  Before you go piddling with someone else's guns, you should know
that.

Pettifogger was quicker on the draw than I.  Drat the luck.

Coffinmaker
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Gabriel Law
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« Reply #7 on: July 18, 2016, 04:09:51 pm »

Thank you both.  I'll peruse the site you have provided.  I do not wish to begin the long learning curve that ends with sufficient experience.  I want it all, right now.  Thankfully, you guys have been there and done that, and even better, are willing to share your knowledge.  My sincere thanks again.

What is a "OEM" mainspring?  My buddy provided me with both the factory spring, and a replacement spring that appeared even lighter than the factory one.
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Montana Slim
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« Reply #8 on: July 18, 2016, 04:50:21 pm »

Stopping by to say "thanks" for the entertainment. Cool
I've got a few handfulls of Uberti OT & RMs (Armys & Navies). As I recall, 3 of them had too LONG of a firing pin. Punching through primers. I merely whittled on them a bit at a time (Medium stone) until that quit. No need to lighten the mainsprings, they feel light normal (light/crisp) Colt types I'm accustom to. Of the multiple sets, only 2 were not properly setup for the arbor/barrel fit (R-M Navies). Funny, also are the two 1860 C&B Uberti I have are perfectly fit from the factory....and I got them from in genuine OEM KIT form. I'm told these are rare...as well as consecutive SN.

So, with all of these LONG firing pins I've encountered..... I'm wondering if the revolver your trying to "fix" has already been "fixed"  Wink

Not that it helps with your predicament.  Roll Eyes
Slim
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Gabriel Law
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« Reply #9 on: July 18, 2016, 07:33:33 pm »

I had a good read this afternoon of Mr. P.'s tutorials on working on these revolvers...excellent reading.  Thankfully, arbor length is perfect and there is no binding whatsoever, and a perfect cylinder gap.  My next thing is to take the pistol to the range and run a box of ammo through it, so I can see for myself if there is a problem.  I removed the helper leaf in the mainspring, and agree that if the factory action doesn't set off primers, there has to be another issue.  I'll be back...

And define OEM please.
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Coffinmaker
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« Reply #10 on: July 18, 2016, 07:38:48 pm »

Original Equipment from Manufacturer.

Coffinmaker
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Gabriel Law
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« Reply #11 on: July 18, 2016, 08:02:01 pm »

Thanks!
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Gabriel Law
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« Reply #12 on: July 18, 2016, 08:04:27 pm »

An aside, risking to derail my own thread...

I checked out the arbor fit of two Pietta 1851s, and four Uberti's.  All have perfect arbor length without having to adjust, using the tutorial as a guide.
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Abilene
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« Reply #13 on: July 18, 2016, 08:40:36 pm »

The long pointy Opentop firing pins that used to pierce primers should be a thing of the past.   Some years back Uberti went with a more conical shape, similar to the replacements from Happy Trails.  But they should be plenty long if they haven't been messed with.  How old is this OT?  As Montana Slim mentioned, if this had the old pointy FP maybe somebody filed it down?  One of my '51 conversions had this issue (different FP style, but still sharp), the 'smith went a bit far when dulling it to prevent primer piercing.  Worked great for 10 years, then started getting the occasional misfire depending on how deeply the primer was seated, so I replaced it (had to dull the new one a bit as well).

Be sure the top end of the mainspring isn't hitting the frame when cocked, nor rubbing the side of the frame (mounted a bit off center).  You can see this by working the action with the grips off.

Make sure the hammer isn't rubbing the side of the frame opening.  Scrape marks on the side would indicate this, as well as feel.  Measure the headspace.  That would be the distance between the cartridge rim and the recoil shield where the firing pin hole is.  And measure how much firing pin protrusion you have through the FP hole with hammer down.  I'm not sure what those values should be, but Pettifogger and Coffinmaker will know.  And is there much or any endshake (cylinder can move front to back)?

CCI primers are the hardest to set off, Winchester medium, and Federals are the softest.  Factory springs should set them all off, but if you are getting misfires with Federals then something is seriously wrong!  Also, be sure the ammo does not have any high primers, as this will cause a misfire.  Usually the first hammer fall will seat the primer, then trying it again will fire.  Since both your buddy's ammo and your primed cases had the problems, I would tend to doubt high primers, but couldn't hurt to check.

Another thing that can cause misfires is the cylinder over-rotating and causing off-center primer hits (or miss it altogether).  This usually only happens with fast cocking, and can be verified by looking at the primer after the misfire.  If you do get a misfire, check to see if the hit on the primer is as deep as ones that go off.  Also do these rounds go off with a second hit?
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45 Dragoon
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« Reply #14 on: July 19, 2016, 08:28:11 pm »

Gabriel,
 I don't know how you are checking the arbor  length  on your open tops but, I have yet to find an Uberti with a usable arbor length, much less a correct arbor length. (Not to mention any Colt 2nd gen O.T.s or the like)
 Likewise, the Pietta's (for me) are slightly long. I like a .002"-.0025" barrel/cylinder  clearance but for out of the box, the Piettas are much closer than any Uberti.

I promise that if you just drop a washer into the arbor  hole, you'll be able to assemble the frame and barrel  with no problem. That means there is a space between the end of the arbor and the barrel assy.  I'm not saying that's all it takes to  fix it, I'm just proving a point.

The mainsprings are pretty much all too heavy and with work on the action parts, a very light main will give you much more control of the revolver and much more confidence in its function.  Pettifogger did a world of good by putting the info up for folks to understand what is happening with their O.T.s . We all owe a huge thank you for that!!

Mike
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Gabriel Law
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« Reply #15 on: July 20, 2016, 08:51:52 pm »

I used Pettifogger's tutorial to check arbor length.. I removed the cylinder, turned the barrel ninety degrees to the frame and seated the barrel on the arbor.  then I rotated the barrel until it came to rest against the frame, checking the alignment of the barrel and frame at the pins.  Perfect!  All of my own revolvers- all purchased in the 70's from our local dealer -Canada's first Uberti dealer! - and they are all so close that I don't see the need to fuss with them.  Perhaps this arbor discrepancy is something on new revolvers.

Incidentally, today, I loaded six Dominion Canuck 38 spl cartridges in the pistol, and they fired perfectly.  Looks like we're good to go.

Thanks much to all of you who contributed to my handgun education.
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45 Dragoon
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« Reply #16 on: July 20, 2016, 10:32:39 pm »

Gabe, Gabe, Gabe .  .  .  .  

 The old Uberti's (maybe all the others) could be checked that way but you can't check new ones that way. They are keyed to fully mate up only when the barrel and frame are aligned correctly. So, you can't check them that way. But, you know what they say bliss is .  .  .  .  .  
I'll try this, and just once. Whatever you do, DON'T try a thin washer in the arbor hole and assemble the gun. They won't go together!  Honestly!!

Good luck

Mike
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Slamfire
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« Reply #17 on: July 21, 2016, 09:23:50 pm »

 Without ,"COFFI&PETTI'S" help and instructions( and  patience),my 72 OT wouldn't be as slick as it is today. I used ,1,5mm ss lock washer in the end of my arbor,,,,,it compressed to a perfect 4 thousandths, clearance ( barrel to cyl.) You would be wise to take heed, to those who'v been there done that, ( just my 2 cent's ).




 Thanks , Hootmix .
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greyhawk
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« Reply #18 on: June 03, 2017, 04:41:10 am »

Gabe, Gabe, Gabe .  .  .  .  

 The old Uberti's (maybe all the others) could be checked that way but you can't check new ones that way. They are keyed to fully mate up only when the barrel and frame are aligned correctly. So, you can't check them that way.

Mike Huh So how to check a newer Uberti ? just keep droppin washers down the arbor hole until we get interference ? I read Pettifoggers stuff - did I miss it in there (was focussed on a couple of old guns at the time so maybe I did?) Some clarification on this would be good thanks . 

Greyhawk
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45 Dragoon
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« Reply #19 on: June 03, 2017, 08:30:23 am »

Greyhawk,
  That is one way. The only problem with that is, the "stack" ultimately gets an adhesive to hold them in place. The more "shims" you have, the more possibility for compression to happen (because of the adhesive).  So, I keep the stack to just a couple of shims at the most.  The metric washers tend to be thicker which makes it easier.
  I do it this way because the various tolerances between manufacturers and even the same manufacturer.  When dealing with a .002"- .003" barrel/cylinder clearance, it's easiest to make the shims fat and dress the arbor down to meet my bbl/cyl clearance.
  I deviate from Pettifogger's method (which would be easier) because I like the idea of an adjustable wedge slot so I leave the end of the arbor open for drilling/tapping for a flat nosed set screw  (1/4"x28)  which allows you to keep your wedge in whatever position regardless of wear. The set screw becomes the front bearing surface for the wedge instead of the forward section of the slot in the arbor (so obviously it isn't protruding past the end of the arbor ).
 
  I have also found you'll have less (or none) compression of the adhesive (JB weld) if you add a considerable amount of metal to the product (I use metal gathered from grinding).

With this arrangement,  Walkers /Dragoons/Army's  hold up to a normal diet of max. loads of 777 and heavy bullets.
My "handgun hunting" folks have given excellent feedback  for this setup as well.

Good luck.

Mike
www.goonsgunworks.com
Follow me on Instagram @ goonsgunworks
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Montana Slim
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« Reply #20 on: June 20, 2017, 05:36:03 pm »

Reminds....BTW, my 3 revolvers with too LONG of a factory FP were.....2x 1860 R-Ms, 44Colt and 1x 1851 R-M, 38Spl.
All three pierced primers until remedied.

My OT has a cone type FP & has worked perfectly.


Slim

Oh...Additional things come into with pierced primers such as as headspace... unless you have an M203 grenade launcher which automatically corrects excess headspace.  Roll Eyes
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« Reply #21 on: June 20, 2017, 06:14:56 pm »

Reminds....BTW, my 3 revolvers with too LONG of a factory FP were.....2x 1860 R-Ms, 44Colt and 1x 1851 R-M, 38Spl.
All three pierced primers until remedied.

My OT has a cone type FP & has worked perfectly.


Slim

Oh...Additional things come into with pierced primers such as as headspace... unless you have an M203 grenade launcher which automatically corrects excess headspace.  Roll Eyes

 In the case of those differently shaped conversion FP's (different from the OT's), I don't think they were too long but too sharp, and needed to be dulled.  I think the new ones are the same.  At least the conversion FP's don't bend like those first long Opentop FP's did.
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