In another thread (350 Legend "timing issues" any more info?) we saw that "timing issues" caused an American Rifleman editor to get a "blast to the face" by a brand new X Frame 350 Legend. The $1600 revolver had to be returned to Smith for repair.

Several forum members suggested that every new revolver should be tested for timing before it's fired. I resolved to do so with my small fleet of wheelguns. First came the Ruger SP101, a boot gun.

Cylinder lockup has slight play when the hammer is down, but at no point during hammer cocking or trigger pull is the cylinder not tightly positioned. Once the hammer is back, the lower lug in the frame seems to engage the cylinder more tightly, because play in the cylinder is reduced to almost zero.

So I'd say that this Ruger passed the test. I'll add the others here as I get to them. My wheelgun collection is small, but I'm fond of them. In a desperate CQC situation in which you're pinned by an adversary, a revolver will always fire even if pressed tight against him.

FYI.

Timing mainly refers to the point at which 2 events occur, relative to each other. Those 2 events are cylinder lockup and hammer fall. Ideally, on S&W revolvers, the cylinder will lock up well in advance of the hammer falling.

If the hammer falls before the cylinder locks, it's called late timing. If the cylinder never locks up before the hammer falls, it's out of time. If the cylinder gets pushed too far CCW, it's out of time, even if it locks up early.

Timing partly refers to whether the cylinder is in correct alignment with the barrel. If it doesn't go quite far enough, or goes too far, it's not lined up with the barrel, and is out of time. When the timing is correct, the cylinder will lock up ahead of the hammer falling, and with the trigger held back, the cylinder will have a slight amount of rotational play. The slight play allows the bullet going from the cylinder into the barrel to fine tune the alignment of the 2 holes as it passes through.

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Thanks for the clarification. On my SP101, the cylinder is locked in place by the cylinder stop on the bottom strap of the frame well before the hammer reaches full cock. So as far as I can tell, it passes that test too.

I found this Midway video that is helpful too. I will run my revolvers thru this process.

Take a rod the will just barely fit down the bore. It does not have to be long. I use a pin gauge from a set precision ground pieces of hardened steel that step up by .001. I slide the largest one that will fit in the muzzle down the bore. The first thing this tells me is if the bore is uniform. Some guns will exhibit a tight spot and the gauge will hang at that spot. If there is no tight spot and I point the muzzle up and put a finger on the side of the cylinder to create some additional drag and ever so slowy pull the trigger the gauge will drop down into the cylinder before the hammer falls. I worry that the harden pin will damage the firing pin tip so I stick pieces of a foam ear plug in each chamber. While it is important that the cylinder stop drops in the cylinders notch prior to hammer fall (carry up) having the bore in line when that occurs is of even more importance. But, even a pin gauge the is bore dia will drop in cylinder with some error as the throat and groove diameter are larger than the land diameter. But that will be handled by the forcing cone in any event as the beginning of the forcing cone is just over groove dia, . On short barrel big bores in good light you can look down the bore for even light and actually see this to some degree.

Look at the forcing cone, is it centered, smooth and even as the lands begin to show in the bore?

If a revolver has late carry up the cylinder stop will drop and lock up the cylinder and the hand will bind as it tries to continue rotating the cylinder. If it is close the trigger will stack (require more pressure) as it forces its way past the ratchet. You can feel this happen when you are adjusting an ratchet for an over sized hand or installing a new cylinder thats ratchet teeth are a bit big. A over size tooth will stop the trigger, then as you file the ratchet for that chamber the trigger will first go by but you can feel it stack as the hand forces by when you are getting close. I have found this with a couple chambers with on brand new revolvers and usually it will work itself out by dry firing. You can verify that this is the reason the trigger stacks by dry firing with the cylinder out. You will have to press the thump piece back in order to pull trigger with cylinder out.

Another thing to look at is barrel to cylinder gap and end shake. Press cylinder forward with finger pressure and using feeler gauges find the gap, then press it back and repeat the measurement. The variation is endshake. How much clearance there from end of yoke tube to center of cylinder bore when center of ratchet is riding on center of recoil shied. This should be under .002 and to me .001 is ideal. B/C gap should be from .004 to .010. Smaller is better to a point, below .004 any fouling may cause drag. A wider gap will allow more gas to escape, but velocity by the inch tested a revolver, first having the barrel tight to the cylinder 0 clearance and fired it, then set it to .001, then .006. The amount of velocity lost was always far greater over the first .001 of gap than the next .005. With 158 gr 357 Federal HP in a 6" barrel they lost .55 fps a .001 gap and just `14fps going from .001 to .006. So while I like to shoot for .004 to .006 I am not as concerned as I once was by .010. as I seriously doubt the velocity loss by that addition.004 amounts to much. I do not carry a feeler gauge with me when I go visiting gun and pawn shops. First I have the tools and ability to fix it. Next you can develop a pretty good "eye" for the gap by looking at enough revolvers. You need to get the gun square to your eye to see the gap.

I also know this. Take something like a 357 or 44 with a normal gap and fire it with construction paper or artist paper say 4 " from it. It will blow holes in it, do that at 12" and you won't get holes, but some powder marks, at 18" it is pretty tiny. I imagine with a higher pressure round like the 460, 5500 or 350 Legend running at 60,000 psi instead of 36,000 the amounts will increase, but quickly drop off as the distance increases.

Here is an interesting observation. Holding a hand gun normally you should not feel any powder peppering on your face. But, if you put that revolver in something like a Ransom rest and move your face closer you will. I figured this out when making a revolver into a carbine, which when used puts you face closer to the frame. It also buts your elbow well down and below the barrel cylinder gap. While the gun is perfectly in time you will feel very light peppering on your face, but Not your elbow.

Thank you for those details. I was just discussing that last point you made today with a fellow Smith fan at church. He said a lot of cowboys got their arms burnt with those revolver carbines. I've never shot one.

It turns out that the only revolvers I have here now are Rugers, SP101 and LCR38. I must have lent the Smith to a daughter. So I just checked my Rugers again using that vid from Midway and all is good. I did find significant differences from Smith revolvers.

There is very little endshake cylinder play on the Ruger SP101, almost none. The LCR has a tad more, enough to feel. But then the LCR is a different kind of beast, more like a Smith Airweight. It's not such a fine jewel as the SP101.

My feeler gauges are for automotive use, all bent up from adjusting valves so I didn't try them on the barrel gaps. I should get some smaller ones that aren't bent. Anyway, the cylinder to barrel gap on the SP101 is so small that I can barely see it using bright backlight. The LCR has more.

I can still check timing on Rugers but some of the other tests such as pulling the trigger while the crane is open won't work on a Ruger. I know this isn't a Ruger forum, just noting that the Rugers are quite different, disassembly too. I've had Smiths apart and they're pretty easy.

BTW, I tried to join the big Ruger forum a year ago when I got the SP101 at a show, and discovered that they blacklist people who use a VPN. Some big Canadian company bought the forum. Not very friendly ... FYI,

Found this several years ago. Found it helpful. (inspection guide)

Attached Files

S&W_revolver_inspection.pdf (195.4 KB, 25 views)

My S&W 69 has what appears to be late timing when the cylinder is empty but is fine with empty cases or live ammo. If it looks like one of yours has late timing try it with empty cases.

One quick and dirty way that I've used over the years is to hold the revolver in my weak hand with my thumb lightly dragging on the cylinder as the hammer is drawn back to full cock. On a correctly timed gun the cylinder stop will drop and fully engage. If it does not and you have to manually turn the cylinder further to get the stop to engage then you probably have an issue with the width of the hand or a worn ratchet or a cylinder stop hanging up- all of which will need new parts fitted. If you hold the closed cylinder at its front with your fingers ay 3 o'clock and 9 o'clock and but lateral pressure side to side and the cylinder and find more than a small amount of play then you have end shake that will have to be shimmed. If you can twist the cylinder and find more than a minor amount of play then an over sized cylinder stop / hand will need to be fitted. If you can shift the cylinder front and back and have more than a small amount of play then the gas block may need to be shimmed. None of these tests are fully definitive but they are a good initial way to determine the mechanical health of a S&W revolver. Rugers are another can of worms entirely...

Dave Lively. That is because the empty cases do a bit better job of aligning the extractor to the chambers than the small pins or odd arms do. I do believe the odd arm ends are a better idea than the old 2 pin arrangement.

The only reason I ever work the trigger on a S&W revolver with the cylinder out is to see if it is heavier or smoother than when cylinder is close. This tells me if the cylinder is dragging or the hand is fighting past a ratchet tooth. To do this on S&W you must hold the thumb piece back as the end of the center piece does that when cylinder is closed and if it is not back the bolt inside the frame blocks the hammer. Keeps the gun from firing if cylinder is not all the way closed.

I have fired my revolving carbine a lot and never once burned my arm. I do not believe many old time cowboys burned their arms with revolving carbines either. Basically a myth perpetuated by people who never fired one and mostly by those who have fired revolvers with the hand or in the case of some sitting shooters having their leg, BESIDE the gap. First of all very few ever existed. Second on most of the revolvers that did have stocks, they were detachable and the barrels, which were also usually not all that long never had forearms to hold on to.

Another point is to hold one by a forearm you keep your off arm's elbow down and under the frame. The gap blast can not go down and through the frame. The frame below the gap causes a cone shaped area under it to be free of gap blast. Plus, your elbow is about 16" below the gap and , the gap blast dissipates quickly over distance it fans out from it.

The blast does not go straight down or up, back or forth. The top strap stops the up portion, the down is stopped by gas rig and bottom of frame, forward by the frame and the majority being funneled down the barrel, to the rear by cylinder and recoil shield.

Simply take a piece off paper and place it underneath a revolver's frame and fire some rounds. even at 4 " directly under it there will be a clean area directly under the frame. The farther the gun is away the larger the clean area. But held 4" off from the side a magnum may well shred the paper.

This one will be even more interesting. Being made from a Ruger Old Army cap and ball revolver. It is supposed to warm up tthe middle of the week so I can try it.



Plus, not being an idiot I wear a long sleeve shirt and as always shooting glasses and my guns time correctly.

A gun myth perpetuated by someone who never fired the gun? No way. That doesn’t happen………. To hear people talk, every Colt revolver has timing issues and anyone that was able to service one is long dead.

BTW Rossi makes a revolving Carbine in 45 colt/410. They added a bit of a blast shield on the frame and yoke to defect a wider area under the frame. Most likely to satisfy their legal department in case a complete idiot bought one.

Mine is a now a straight up 45 colt, when I first built it I had a cylinder in it set up to fire 45 colts and 45acps. I have fire a couple hundred rounds thought it with no problems. While it is easier to hit a target with at 150 yards than a regular hand gun, I can easily hit a paper plate with it at 100yds using double action, it is mostly just a novelty, that I built because I could. It would be great for going into heavy cover after whitetail though.

When I perform S&W revolver timing test (SA and DA), I just slowly advance through making sure the stop releases and then engages to the next in battery before hammer drops (or engages to SA), then I just ride the hammer back down (before it dryfires). If I can get through all chambers this way I am certain it’s good. I also use the open cyl as control comparison test mentioned above.

But I have a question, is it OK (once stop engaged and cyl solid in place) to ride it back down from battery (under loaded mainspring tension) instead of going a hair more and dry firing, would this cause increased wear on sear, hammer, and trigger surfaces?

I do the same Steve. Sellers tend to get nervous and jerky if you dry fire their guns. I guess you could bring snap caps to inspect a prospective purchase.