'51 Opentop problems

[5judge]

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Enthused by a several-years-old "American Rifleman" report, I bought new a Cimarron Uberti 1851 Navy open top in .38 Special. It functions, unloaded, just fine. It functions when loaded just fine. However, with the first shot fired, the cylinder must thereafter be hand turned to cock and advance to the next chamber. My handloads slip easily in and out of the piece and I'm using black powder with a properly seated round nose lead bullet. What's going on here?

[Pettifogger]

There are dozens of things that could be wrong, hard to tell from the brief description.  First, are you using real BP or a sub?  Are you using a full charge?  Wuss loads of APP sometimes won't generate enough pressure and the primers can back out.  Is there a burr around the firing pin hole?  Have you measured the cylinder gap?  Have you checked end shake?  Have you checked the head space?  Have you checked the arbor fit?  Etc., etc.  Almost all Ubertis have terrible barrel to arbor fit.  What happens a lot of times is that as the wedge is pushed in the barrel will tilt and close the cylinder gap or the gap will be close at the top and wide at the bottom.  The barrel can also be putting pressure on the gas ring.  As soon as you fire the gun fouling closes what little gap there was and the cylinder drags.  There is no such thing as a 51 Navy in .38 Special.  You have a conversion of some sort, precisely which model do you have?  Is the backing plate loose?  Lots of potential problems and fixes.  You need to try and explain in more detail what your gun is doing.

[Mako]

5Judge,
Pettifogger is dead on.  There are a bunch of folks here who can help you.  Answer all of the questions Pettifogger asked and then any others that are  posed to you and we can get to the bottom of this.

I have a few more to add to the list.
1. What is the bullet weight of your loads?
2. Are they commercial loads, if so give us the manufacturer.
3. If they are handloads what is the exact load?
4. When you look at the primers on the fired cases exactly what do they look like?  A picture would be perfect here.
5. On the fired cases, are the primers flush, or slightly proud above the base of the case?
6. What is the shape of the firing pin dimple on the primers?  Are they sharp, or rounded? is there a crater raised around the dimple?

That's a start foe me.

Have a nice evening,
Mako

[Abilene]

One more important question: have you tried the gun with smokeless loads?

[5judge]

Thanks for the interest. I've reloaded for 40+ years, so am not unacquanted with some of the problem signs. Have fired perhaps a hundred rounds, total, from this revolver. Bullets are 125 gr. round-nose which I've cast, SPG lubricant. Powder is FFFg Goex, lightly compressed. Some rounds included Ox Yoke felt wads. Primers are all seated below face of cartridge base and, fired, show no sign of cratering nor backing out. Firing pin impact reasonably centered. Fired cases ejected easily. .38 special brass is mixed, once-fired. (Revolver is chambered for .38 Special). No smokeless loads have been fired from this piece, bought new. I'm stymied. Naturally resist the inconvenience of sending it back to Cimarron.

[Pettifogger]

Read these, take two aspirin, and report back in the morning. 

http://www.theopenrange.net/forum/index.php?topic=7988.0

[Abilene]

The reason I asked if you had shot smokeless in it was to find out if the problem is likely due to fouling on the cylinder face.  One of my '51 Richards-Mason conversions had that problem.  I could shoot one or two rounds of BP before it stopped turning.  Smokeless was okay.  This was related to an insufficient barrel to cylinder gap caused by some of the things Pettifogger has mentioned (not fitted properly by Uberti, which let it shoot smokeless okay but not BP).  I would not send it back to Cimarron if it shoots okay with smokeless.  Technically, handloads voids the warranty.  Now they won't void it if the gun has not been harmed, but they will test the gun with Black Hills Ammo smokeless rounds and if it shoots okay they will probably tell you it is within spec.

[Major 2]

That's a about the truth    and Abileen works there !

I have 51 Richards for Cimarron it worked great with Black Hills  but would bind with BP Black Daug...

best $125 I ever spent was by-passing Cimarron and sent it direct to Longhunter.... He worked his magic on the action and then even jeweled the Hammer for free  ( he asked first )

[5judge]

Many thanks. I shall try smokeless powder next time the weather lets me out. I developed some light-moderate loads for my daughter to practice with in her S&W Bodyguard. if it works, OK, but I sure lwould miss that smokey black powder ambiance! wonder of Pyrodex would work, too. I'll experiment.

[Harley Starr]

That's a about the truth    and Abileen works there !

I have 51 Richards for Cimarron it worked great with Black Hills  but would bind with BP Black Daug...

best $125 I ever spent was by-passing Cimarron and sent it direct to Longhunter.... He worked his magic on the action and then even jeweled the Hammer for free  ( he asked first )

I'd like to see that.

[5judge]

My especial thanks to Abilene; got the revolver out to the range today with a box of .38 Specials loaded with Bullseye (I've got enough Bullseye given to me to see me out). Pistol cycled flawlessly. It was the black powder residue between the cylinder face and the barrel breach which was tying her up; very tight tolerance. Now if I can just hit something smaller than a Guernsey cow at 40 yards with it....

[Mako]

ummmm...
There's just something unseemly with putting "smokiless" powder in a '51.  Just 'taint right...

So now that you know the problem you can get the cylinder gap corrected to be .006"-.008".  Before you do you may consider having the modifications Pettifogger has written about in the Chronicle done to your pistol.  Otherwise you'll have to make sure you set your wedge the same way each time the barrel is removed.  Not hard to do once you understand the relationships, but it isn't the ultimate solution.

Here are links two the two parts of the articles Pettifogger wrote that are relevant to the cylinder gap being controlled in part by the arbor length on the Uberti open top framed pistols.

http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_3.pdf

http://www.theopenrange.net/articles/Tuning_the_Uberti_Open_Top_Revolvers_Part_4.pdf

Glad you had fun and don't worry accuracy will come, those pistols point well.

Regards,
Mako

[Raven]

.006 end gap is proper for a modern revolver, But, .008 -.010 is correct for a conversion revolver.
Chicoine says an even larger gap is OK as long as the revolver functions correctly.

Black Powder definatly needs the larger gap and conversions in general need this larger gap for the single stage hand to operate correctly.

Raven

[Mako]

Raven,
If your talk'n about a Ned Christie conversion of a '60 to .44-40 (HAAAAAAAAAAAAAA) I'd agree with you.  Where did the Fox Creek Kid hear that one?  But, that's about par anymore.

I run my cap guns .008"-.010" (I try to set them up .008 to .009) and I run my cartridge guns including Uberti conversions, '72 Open Tops and '73s .006"-008".   I hear you and respect your experience.  I have just been shooting them that way for a long time and they work very well.  I also have an ASM Richards type 1 which I'm not sure how it's set.

You are wrong about one thing though, which is entirely forgivable because you work with actual "conversions."  The pistol he owns has a two stage hand.  Uberti Richards-Mason conversions don't have the original single stage hand.

I have several pairs in different flavors, and they all have two stage hands. With a true single stage hand and the length it has to reach you are probably right, which is one of the reasons I use a larger cylinder gap on my cap guns which have the single stage hand.

I enjoy your posts and keep up the good work.

Regards,
Mako

[Fox Creek Kid]

Raven,
If your talk'n about a Ned Christie conversion of a '60 to .44-40 (HAAAAAAAAAAAAAA) I'd agree with you.  Where did the Fox Creek Kid hear that one?...

Don't quote me, but I think I read the part about the converted 44-40 in the old "Guns and the Gunfighters" by the Editors of Guns and Ammo - Bonanza Books. I had a copy years ago.

[Coffinmaker]

There is also another cheap seats way to set the depth of the arbor in the barrel.  Drop by your local DIY store and pick up a couple of 5mm split washers (I use stainless).  Drop one down the barrel bore for the arbor, seat the barrel on the frame and tap the wedge home.  I don't know the specifics of Uberti's machine work, but the 5mm washer seems to be correct in 98% of the Open Top guns that DO NOT have the cuts for the rammer.  Just remember to put the washer back in each time you tear down for cleaning.  DO NOT attack the back of the barrel for barrel/cylinder gap until you have corrected the arbor fit.

Coffinmaker 

[Sgt.Jake]

Coffinmaker   +1 on the 5mm split or wave washers. I used a dab of E 6000 silicon based adhesive to retain the washers. Two OT done that way and have not lost the washers in over five years.       Adios  Sgt. Jake

[5judge]

Duh. What's a "DIY store"? If there's no such thing in western North Carolina, what is the type of business in which I'd likely find this type of washer? Thanks.

[Mako]

A DIY store is a "Do It Yourself" Store.  He's talking about a Home Depot, Lowes or a plain Hardware store.

You can get them online from McMaster-Carr who I believe I am supporting almost by myself when I look at the engineering groups purchases from the last quarter.

http://www.mcmaster.com/#91169a170/=agkzax

This is a good choice.  It's un-plated, it's steel (not stainless), it has a black oxide finish and it is a good thickness and diameter for a Uberti Arbor hole (arbors run around Ø.42. I don't know if Coffinmaker lives where metric is the standard, but after comparing a few sizes, a metric washer like he specified is actually better for this application.  The thickness of the English sizes in the diameters needed tend to run too thick, you can drop a screw size from #10 to #8 but then you get less contact area.

The price is $2.26 for 100.  There is an alternative which is a wave washer Part # 90134A029.  I've tried those but they are $11.25 for 50 and they are only .01" thick. But if you want a spring fit it works well (you lose them a lot if you load off pistol).

Coffinmaker is using the split washer as a spring to take up the difference in thickness needed to bottom the arbor in the barrel channel. The washer is 1.1mm thick which is .043" the gap on a Uberti between the end of the arbor and the hole probably runs around .05".

Good call Coffinmaker, I hadn't considered metric.

You can buy online and have your parts tomorrow, the shipping may get you though they have charged us $5 for little things and at others $1.75.  You can call your order in if you wish and thy will probably tell you the shipping charge.

Regards,
Mako

[5judge]

Have a pack of McMaster-Carr washers on the way. 100 of the little buggars. Now I need 99 more opentop shooters....

[Montana Slim]

Cylinder to barrel gap on 2 each Uberti 1860 & Pietta 1860 Colts (Percussion) that I most frequently use run no more than .004".
And I assure you they function quite well even using Elephant BP.

A larger gap doesn't hurt on some revolvers, depending on their particular design features.

Regards,
Slim

[5judge]

OK. Dropped the newly acquired washer in the open top and reassembled. Shall report back when I can next range it. Right now ten inches of fresh snow's keeping me home, happily casting .358" bullets and watching "Last Stand at Saber River" on DVD in my basement work room.

[Mako]

5judge,
Do you have any feeler gages?  I'm talking about flat gages that you may have used to set spark plug gaps or points on your cars in the past.  If you do I'm curious as to what your cylinder gap is right now.

If you don't have gages, use paper.  Use notebook paper, don't measure with a folded edge (it will be thicker).  One sheet will run about .0030 -.00325"; so you want two sheets to fit for your cylinder gap.  That will give you a gap of .006 to around .009".  If three fit you are over .009".

When you measure have the pistol un-cocked and put slight rearward pressure on the cylinder to make sure you are measuring your maximum gap.

To make sure the washer is actually doing something think back to when you when you replaced the barrel after adding the washer, did it hold it off of the face before you put the wedge back in? You have a 99 left, so you might want to try it again with a fresh washer and observe what happens.

An even better idea would be to remove the washer, reassemble the pistol and then measure your gap.  Then add a fresh washer and try it again.  The only reason I am suggesting a fresh washer is that it will take a slight set the first time you install it.  I want you to feel the interference (to make sure it is there) the first time it is compressed.  Now remeasure your gap.

Hopefully it went from zero or one sheet of paper to now accepting two sheets of paper.  Or if you have feeler gages; from .003" or less to .006-.008".  If it accepts three sheets or is greater than .009" with a feeler gage you need to back off on the amount your wedge is pressed in.

Since you have a Uberti Richards-Mason the wedge has that slot and the screw that has the flat cut on it.  I know some people don't like the idea, but you can use that slot and the screw to set your length. I like to use the minimum engagement that will retain the wedge on any new set-up of a pistol.  This gives you additional tightening capability if the pistol wears over the years.  If you bottom it out the first time you will have no additional adjustment over time.

Since you are using a spring (the washer) and not a true hard stop at this point, you can "over-tighten" the wedge and close the gap.  The washer gives resistance and makes it much easier to set the gap. Try this simple procedure to set your gap:

• After replacing the barrel tap your wedge in until you see the clearance slot on the wedge just pass the edge of the barrel.
• Turn the screw down, the edge should now be blocking the wedge.
• Tap the wedge back very lightly to just touch the screw.  (this is the minimum engagement possible with your screw fully tightened)
• Check your gap.  If it is less than two sheets of paper or .006" then you will need to move the wedge out.  If it accepts three sheets or is more than .009" then we need to move it in deeper.
• Moving it out a controlled distance is the easiest change at this point.  You back the wedge screw out a complete revolution, the screw's pitch is .028 per inch so the screw will move out that much.  Now tap your wedge back to the screw and remeasure.
• Remeasure, and it should be at least .001" greater than it was before.  The wedge taper is only about 2°15' overall.  So you can turn your screw out however many full revolutions you need (at a gain of .001" per turn) to get your gap of .006-.008".
• Going smaller is tougher to gauge because you lose your screw as a reference point.  The good news is that this shouldn't be a problem for you because by all indications your gap started too tight.

If you find a washer that literally fills the gap in the arbor to arbor hole relationship the gap is preset each time you reassemble.  A purpose built spacer is even better, that is the ultimate solution.  Did you read Pettifogger's articles in the links I posted for you?  Once this is set, the gap can't change as long as you have some wedging action.  You want to slightly "spring" the barrel lug every time the barrel is reassembled.  I have an original 1860 built in 1861 and it still does this.  The creep of steel (even wimpy 1860's time period steel) is low and it has held up for 149 years.  As long as you don't drive the wedge in with a 5 pound hammer the steel acting as a spring should keep you out of trouble.

I shoot loose powder 1860's almost exclusively in matches and I reload off of the pistol, which means I disassemble them every 5 shots.  I have mine set so that I tap the wedges in until the spring lip (you don't have one on your Uberti cartridge pistol wedge) just clears the barrel on the other side. I do this to aid in dis-assembly in the next few minutes.  It also serves as a visual indicator I have reassembled the pistol correctly.  With this insertion a few taps with a wooden dowel disassembles the pistol.  I have not experienced any measurable wear over the years of doing this with constant dis-assembly.

Regards,
Mako

[Rebel Dave]

Mako, FCK, Raven, and all

Thanks for some good info on open tops, and C&Bs. I am now working on my 4 open tops, including my 2 45s, after that come my C&Bs. Lots of good info in this thread. Thanks guys.

Rebel Dave       aka      Dave C.

[StrawHat]

Marking for reference