Vaquero misfires

[johnmuir2013]

I have two SASS Ruger New Vaqueros, 4.62", 357.  One of them is misfiring approximately 10% of the time due to off-center primer strikes.  It happened Saturday Sept 17, 2022.  So, after that match, I did a complete disassembly and clean.  But then it happened again Saturday Sept 23, 2022.  In other words, a thorough cleaning didn't help.  The spring tension on the cylinder latch seems fine and seems the same as the pistol that works.  I can't get the indexing to fail in my house using dummy rounds.  Does anyone know what I should do? 

 

[Eyesa Horg]

Exact same thing happened to one of our shooters this weekend. Couldn't seem to make it happen either. His hits didn't quite hit the brass though. Good luck.

[Attica Jack #23953]

Wow, that is really strange.  The only thing I could think of is, that the firing pin is broken and both parts are kept in place by the transfer bar.

[Eyesa Horg]

The one my Pard had was random, we marked the chamber and it was completely random, but one chamber every time! I don't think he was shooting a Ruger though.

[Hendo]

Are both pistols brand new, out of the box stock?

[Colorado Coffinmaker]

Sure.

 

Disassemble several of the failed rounds (kinetic bullet puller) and package several of the cases up with the miscreant pistol and ship it back to Ruger for correction.  Insure Ruger can see where the primer strikes are.

[largo casey #19191]

I have a Uberti that did it once on the first stage of a 10 stage match.Hasn't done it since.

                                                                                                                                                                          Largo

[largo casey #19191]

Forgot.It has Pietta Bisley hammers.

                                                         Largo

[Sedalia Dave]

It would help to know the following;

 

Are the off center hits are due to the cylinder not indexing fully or is the cylinder over indexing?

 

Does it always occur on the same chamber?

 

What gunsmithing has been done to the pistol in question?

 

How long have you been shooting these pistols?

[Not Dead Ed]

Remember if you have any non-stock parts on the Vaquero, take them off and put the originals back in.  Ruger will put it all back to stock when they service it. 
I’d check your bolt latch spring on the grip frame.  It could be out of place, or the detent is missing.  Also check on the loading gate spring’s placement….  Right now it’s over rotating and not latching in I think.  

[Not Dead Ed]

23 minutes ago, largo casey #19191 said:

I have a Uberti that did it once on the first stage of a 10 stage match.Hasn't done it since.

                                                                                                                                                                          Largo

So did too  and it was the bolt latch spring (a wire one) that went out of place.   I only use the flat springs in the clones now.  Wire may be more robust, but they might wander off like mine did.  

[johnmuir2013]

1 hour ago, Sedalia Dave said:

It would help to know the following;

 

Are the off center hits are due to the cylinder not indexing fully or is the cylinder over indexing?

 

Does it always occur on the same chamber?

 

What gunsmithing has been done to the pistol in question?

 

How long have you been shooting these pistols?

My SASS NMVs are about 10 yrs old.  Each one has had about 5000 rounds fired out of it.  (5 rounds x 5 stages x 2 people x 10 matches per yr x 10 yrs).  They both have Wolff spring kits.  That is their only customization.  
I don’t know if the problem pistol is over indexing or under indexing.

I don’t think the misfires happen in the same chamber because my wife had two misfires in one stage from one pistol.

 

[40Chev]

Mine did it to the point of aggravation - smith cut the cylinder notches deeper and that solved it for me.

[Cheyenne Ranger, 48747L]

my brother had a pair of Rugers he got used.  One would do that.  the "gunsmith " that worked on it lowered the height of the cylinder latch to try to get the gun to go faster.

 

new part and he was back in business

 

 

[Dusty Devil Dale]

Make sure the plunger below the cylinder latch in the lower frame  consistently AND FULLY engages  the bottom of the cylinder latch.  The plunger's function is to confine the flex of the spring, thus precisely pisitioning the lift of the spring against the bottom of the  latch, to lift the latch enough to engage the cylinder notches.  Try to wiggle the latch plunger back and forth.  If it can shift laterally more than a half-millimeter each way,  the top of the plunger might be missing the latch occasionally.  The latch body might show a wear mark where it is occurring. 

 

One of my NMVs came from the factory with the plunger hole bored slightly at a lateral angle-- just enough to enable the plunger to occasionally miss to the side of the latch. Realize that the latch itself also has a small amount of lateral wiggle and the two movements combined were enough to enable an occasional contact failure. With use/wear, the problem frequency increased. 

 

The location of the blind vertical boring, inside the frame, made if difficult to re-bore/correct the hole alignment, so I made a new plunger with a +- 4mm wide cap at the top.   That corrected the problem. 

 

I've never seen or heard of the problem occurring on any other gun, but mine did exactly what you are reporting.   It is at least worth a look. 

 

I am referring to parts #9 and #10 on the diagram below. (not the gate spring #21)

 

[Tucker McNeely]

Is the hand worn?  With that many rounds fired,  you might need a new hand.   Remove cylinder and compare what the face of the hand looks like compared to a newer one. 

 

With empty gun, run "ring around the ruger" and see if there us rotational play in the cylinder when it comes around to lock up. 

 

May have issues with the bolt fitting securely in the notches also.  What does the bokt look like?  Is there too much play in the bolt?

[Sedalia Dave]

3 hours ago, johnmuir2013 said:

I don’t know if the problem pistol is over indexing or under indexing.

 

Easy to tell. Next time it misfires look at the cartridge head BEFORE you remove it from the cylinder.

 

Holding the pistol vertical with the loading gate open look at all the the cartridges and see where the firing pin is hitting. .  If the strike is on the bottom of the cartridge, it is failing to fully index. If on the top of the cartridge, the cylinder is over indexing.

 

Failing to fully index points to a problem with the hand

 

Over indexing means the bolt is not properly engaging the cylinder.

[The Original Lumpy Gritz]

Try switching cylinders 

[Abilene, SASS # 27489]

3 hours ago, The Original Lumpy Gritz said:

Try switching cylinders 

Having cylinders accidently in the wrong guns has caused strange problems for more than a few folks.  

[J.S. Sooner, SASS #73526]

I had a similar issue with new Rugers, the cylinder would not advance properly because of some machining debris and a small burr holding up the pawl plunger.  After cleaning and removing the burr they have worked for 16 years.  

 

Try tilting the muzzle up while cocking the hammer to see if the cylinder rotates properly, then again with muzzle down.  Gravity would allow the pawl to engage and rotate the cylinder but the pawl plunger wasn't working as it should.

[Assassin]

One of our shooters had the same thing happen. The cylinder wasn't locking up on one chamber. We could cycle the action and duplicate the misfire every sixth time, weird huh? It would lock up fine when we pulled the hammer back like a non-SASS shooter, when snatching the hammer back really hard it would not lock up on the same cylinder. If you drop that hammer and it's just slightly off center you could blow that gun apart, don't shoot it. The loading gate spring had a weird bend from the factory. When I swapped it out the gun locked up on all cylinders. The index plunger can get sticky, especially if you live in a humid climate. I replaced the plunger and spring also. If it was just the plunger it would have skipped on all chambers. 

[J.S. Sooner, SASS #73526]

2 hours ago, Assassin said:

 If it was just the plunger it would have skipped on all chambers. 

Not in the context I posted about.  Mine would work fine if gravity let the pawl engage the cylinder. It only missed when cocked while the muzzle was slightly up while cocking.  

 

[johnmuir2013]

Solved!

1. I called Ruger.  The Ruger tech said to send it in to Ruger, but I convinced her to send me a new cylinder latch.  She agreed but added that she didn't think that would fix the problem.  I've inserted a photo of new vs old cylinder latch.

2. As per August West's suggestion, using my 1" belt sander and a 600 grit belt, I sanded the trailing edge of the cylinder latch's tit that falls into the cylinder's locking grooves.  Using my Dremel tool, I polished it with a buffing wheel.  The cylinder's locking grooves are 0.093" wide, and the cylinder latch is 0.087" wide - only 6 thousandths different.  Grinding a little off the cylinder latch's trailing edge gives the latch a better chance of fully entering the cylinder's locking grooves.  Photo is attached.

3. At the range, I fired 24 rounds (loaded 6, four times) into the berm as fast and vigorously as I could.  No misfires!!!

 

Thanks to all who had suggestions.  

 

One remaining point of concern is that the cylinder latch plunger's hole in the grip frame is crooked which makes the plunger sit tilted to the side.  I did not do anything about this but it's worrisome.  Photo attached.

 

 

[JP McLintock]

Glad to hear you got it fixed, we had a great time shooting with you at fall round up.

 

Jp

[Larsen E. Pettifogger, SASS #32933]

The latch plunger is supposed to be tilted to the rear and left.  Who ever did the rounding on the old latch ruined it and I would not have taken material off the trailing edge.  But if it works for you that is good.

 

 

.

 

 

 

[Dusty Devil Dale]

My latch plunger tilted toward the right.  But the 4mm expanded head plunger that I made corrected the mis-contact.  

[The Original Lumpy Gritz]

OP, did you receive a ground or unground cyl latch?

The ground one should not need to be narrowed any more.

That leads to excessive rotational play.

 

[Mustang Gregg]

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