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Bill Akins · January 19, 2011, 11:01 PM

There are several issues involved here.

The first thing to know is the reason why colt put the lead in grooves on the cylinder in the first place. That reason is just as valid today as it was back then. In an absolute perfect timing situation the bolt would rise and engage the locking recesses on the cylinder without ever touching the outside and ringing the cylinder. You can time it so it will do that. But....that is only if you cock it exactly the same way and at the same speed each and every time.

When you cock the revolver slowly, the cylinder does not rotate as fast nor have as much rotational inertia as it does when you cock it rapidly. So if you adjusted your timing for perfect bolt drop to slot engagement you would never have a problem. But....if you had it adjusted that way, and then you cocked it rapidly, the cylinder would rotate faster and have more rotational inertia which would cause your cylinder to rotate too rapidly for the slow timing you have set it at, which would cause your cylinder too travel too fast for your bolt and then the cylinder would overtravel before your bolt dropped. (The term bolt "drop" means the bolt rises up to engage the cylinder slots). It can get confusing to folks not familiar with the meaning.

As you can see, this created a situation where if the timing was set absolutely perfect for slow cocking, it would not be set perfect for fast cocking and the cylinder would overtravel. So....colt created the lead in grooves on the cylinder just before each cylinder slot. This is so your timing will work either with slow cocking or fast cocking. The bolt should rise up at the beginning of the lead in groove and then "pop" into place as the cylinder slot rotates to engage the bolt. The lead in groove makes sure your bolt is dropped and ready to go into the cylinder slot no matter whether you have cocked it fast or slow.

Although you can't see it if cocking fast, when you cock it fast, the bolt will actually rise up later in the lead in groove than it will when you cock it slowly. That is because the speed of your cylinder rotation is faster on fast cocking and tries to overtravel your bolt. But the cylinder won't overtravel your bolt as long as you have your bolt timed to drop as the edge of the lead in groove comes into alignment with the edge of the bolt. Your bolt SHOULD drop and engage the lead in groove so it will be ready to "pop" into the slot. That is the purpose of the lead in groove and is proper and normal timing for whatever cocking speed. Yes eventually that will show a mark on your lead in grooves from the blot riding in them. That is also normal. But you can minimize that mark by loosening the tension on your bolt/trigger spring as I describe below.

Luckily on the colt you DO have the lead in grooves. On my 1858 Remington, I don't have the lead in grooves and have to set my timing so that my bolt just barely rises at the edge of my cylinder slot and then as the cylinder continues to rotate the bolt will "pop" into place. That causes a little teeny score mark about 1/32's to 1/16th's of an inch before my cylinder slot. But this is normal. If I had my Remington set to where the bolt rose exactly perfectly as the slot came into engagement with it, the cylinder could overtravel the bolt rise on fast cocking. To minimize the teeny score mark, I lessen the tension on the bolt/trigger spring on my 1858 Remington as I describe to you below later on.

Most used revolvers will have some score marks on their cylinder lead in grooves or a slight ringing around the cylinder. This is just the nature of the mechanics. It can be minimized by proper timing and proper bolt spring tension, or even by filing the head of the bolt at an angle so it will lessen this "ringing" line. But will be seen to some extent on any used black powder revolver. Just one of those things we learn to live with and adjust for. And replace when it gets worn out as does anything.

If your revolver is timed to where your bolt rises at the beginning of the lead in groove, it is properly timed. If you are getting "dings" or "peening" of the edge of the cylinder slot, then back off a bit on your bolt/trigger spring (not the main hammer spring). Backing off a bit on the spring will lessen the tension on the bolt and it will not drop as hard and lessen the "peening" on your cylinder slot edges.

The bolt is a hardened piece of spring steel since its legs have to be tempered to be a spring which presses against and rides up on the hammer cam to teeter totter the bolt as the hammer is cocked. So the bolt is harder than your cylinder and will "ding/peen" the edge of your cylinder slot if the tension on your bolt is too strong. Again, try loosening up on your bolt/trigger spring. Take the cylinder out of the revolver and take off the trigger guard so you can access the bolt/trigger spring. In a trial and error basis, loosen the tension on the spring and cock the revolver to watch the bolt rise up. Push down a little and then release with your finger on the bolt when it is fully risen up. If the bolt goes back down after your pushed on it and did not come fully back up after you released it, your spring tension is too little. Loosen and tighten the spring until you can tell that the bolt fully rises at full cock but is not under undue tension. You do not need as much tension as the spring will put out. It is not necessary and can cause the "peening/dinging" problem you are currently having. All you need is enough bolt tension so that it will rise up and engage the cylinder slots. Just make sure you don't have too little tension either or the bolt can slip out of the slot on fast cock and then you will have cylinder overtravel.

If your bolt is rising too soon and scoring your cylinder BEFORE the bolt is aligned with the lead in slots, that could be caused by a worn cylinder ratchet hand/pawl. That would cause your cylinder to not start turning until the worn hand/pawl engaged the ratchet. If the tip of your hand/pawl is worn, your cylinder will start turning late. That means the bolt will drop off your hammer cam before the cylinder is ready for the bolt to rise into the lead in grooves. To fix this there are two ways. 1. Get a new hand/pawl. 2. Take your old hand/pawl out and set it on a flat metal surface and taking a hammer and punch, carefully "peen" the hand/pawl to elongate it. Now the either new, or "peened" longer hand/pawl will start revolving the cylinder when it should instead of doing it late.

If a bolt is dropping too late and "dinging/peening" the aftermost rear edge of the cylinder slots, you might need to file the leg on the bolt where it engages the cam on the hammer so that the bolt leg drops off the hammer cam earlier. As the hammer is cocked, the cam on the hammer engages the spring tempered leg on the bolt causing the rear leg of the bolt to rise which causes the teeter totter effect which unlocks the bolt from the cylinder. If that hammer cam is worn, it will cause your bolt leg to drop off the cam too early. If your hammer cam is fine but the bolt leg is worn it can cause the bolt leg to drop off the cam too early. And if your bolt leg drops off the cam too late, then you need to file the bolt leg so it drops earlier.

Here is what I do. I inspect the hammer cam. If it is okay then the problem is the bolt. Next I inspect the bolt, if the leg appears okay, it is possible that the leg has just lost a little spring tension where it pushes up against the hammer cam. If I am thinking I am going to have to replace the bolt because the leg is worn out anyway, before I do that, I will VERY CAREFULLY (because it is a tempered spring and will break very very easily) try to spread the bolt legs apart just a little so I re-new and increase the tension of the bolt leg against the hammer cam. If that works then great, otherwise it is time for a new bolt. It's a good idea to have a few extra bolts, bolt/trigger springs, and hand/pawls in your spare parts kit when you go shooting. Also get yourself a good set of NON tapered, counter bored, screwdrivers so you don't mess up the screw threads. And get a little kit of fine needle files too. Also known as Jeweler files. Get a fine filing stone too.
The stone will take off less metal then the files and is good for careful tweaking of parts for timing. A little 220, 400 and 600 grit sandpaper and some small wooden blocks to wrap it around is good too. Even some of the ladies emory boards for filing their nails work for fine tuning timing too. The idea is to always take off less than more and then try it. You can always take off more metal but it is hard to add to once removed.

I hope this helped you understand correct revolver timing and how to fix some problems with that timing.

If you have any other problems I didn't cover, let me know and I will try to help you figure those out.

January 19, 2011, 11:01 PM	#5
Bill Akins Senior Member Join Date: August 28, 2007 Location: Hudson, Florida Posts: 1,135	There are several issues involved here. The first thing to know is the reason why colt put the lead in grooves on the cylinder in the first place. That reason is just as valid today as it was back then. In an absolute perfect timing situation the bolt would rise and engage the locking recesses on the cylinder without ever touching the outside and ringing the cylinder. You can time it so it will do that. But....that is only if you cock it exactly the same way and at the same speed each and every time. When you cock the revolver slowly, the cylinder does not rotate as fast nor have as much rotational inertia as it does when you cock it rapidly. So if you adjusted your timing for perfect bolt drop to slot engagement you would never have a problem. But....if you had it adjusted that way, and then you cocked it rapidly, the cylinder would rotate faster and have more rotational inertia which would cause your cylinder to rotate too rapidly for the slow timing you have set it at, which would cause your cylinder too travel too fast for your bolt and then the cylinder would overtravel before your bolt dropped. (The term bolt "drop" means the bolt rises up to engage the cylinder slots). It can get confusing to folks not familiar with the meaning. As you can see, this created a situation where if the timing was set absolutely perfect for slow cocking, it would not be set perfect for fast cocking and the cylinder would overtravel. So....colt created the lead in grooves on the cylinder just before each cylinder slot. This is so your timing will work either with slow cocking or fast cocking. The bolt should rise up at the beginning of the lead in groove and then "pop" into place as the cylinder slot rotates to engage the bolt. The lead in groove makes sure your bolt is dropped and ready to go into the cylinder slot no matter whether you have cocked it fast or slow. Although you can't see it if cocking fast, when you cock it fast, the bolt will actually rise up later in the lead in groove than it will when you cock it slowly. That is because the speed of your cylinder rotation is faster on fast cocking and tries to overtravel your bolt. But the cylinder won't overtravel your bolt as long as you have your bolt timed to drop as the edge of the lead in groove comes into alignment with the edge of the bolt. Your bolt SHOULD drop and engage the lead in groove so it will be ready to "pop" into the slot. That is the purpose of the lead in groove and is proper and normal timing for whatever cocking speed. Yes eventually that will show a mark on your lead in grooves from the blot riding in them. That is also normal. But you can minimize that mark by loosening the tension on your bolt/trigger spring as I describe below. Luckily on the colt you DO have the lead in grooves. On my 1858 Remington, I don't have the lead in grooves and have to set my timing so that my bolt just barely rises at the edge of my cylinder slot and then as the cylinder continues to rotate the bolt will "pop" into place. That causes a little teeny score mark about 1/32's to 1/16th's of an inch before my cylinder slot. But this is normal. If I had my Remington set to where the bolt rose exactly perfectly as the slot came into engagement with it, the cylinder could overtravel the bolt rise on fast cocking. To minimize the teeny score mark, I lessen the tension on the bolt/trigger spring on my 1858 Remington as I describe to you below later on. Most used revolvers will have some score marks on their cylinder lead in grooves or a slight ringing around the cylinder. This is just the nature of the mechanics. It can be minimized by proper timing and proper bolt spring tension, or even by filing the head of the bolt at an angle so it will lessen this "ringing" line. But will be seen to some extent on any used black powder revolver. Just one of those things we learn to live with and adjust for. And replace when it gets worn out as does anything. If your revolver is timed to where your bolt rises at the beginning of the lead in groove, it is properly timed. If you are getting "dings" or "peening" of the edge of the cylinder slot, then back off a bit on your bolt/trigger spring (not the main hammer spring). Backing off a bit on the spring will lessen the tension on the bolt and it will not drop as hard and lessen the "peening" on your cylinder slot edges. The bolt is a hardened piece of spring steel since its legs have to be tempered to be a spring which presses against and rides up on the hammer cam to teeter totter the bolt as the hammer is cocked. So the bolt is harder than your cylinder and will "ding/peen" the edge of your cylinder slot if the tension on your bolt is too strong. Again, try loosening up on your bolt/trigger spring. Take the cylinder out of the revolver and take off the trigger guard so you can access the bolt/trigger spring. In a trial and error basis, loosen the tension on the spring and cock the revolver to watch the bolt rise up. Push down a little and then release with your finger on the bolt when it is fully risen up. If the bolt goes back down after your pushed on it and did not come fully back up after you released it, your spring tension is too little. Loosen and tighten the spring until you can tell that the bolt fully rises at full cock but is not under undue tension. You do not need as much tension as the spring will put out. It is not necessary and can cause the "peening/dinging" problem you are currently having. All you need is enough bolt tension so that it will rise up and engage the cylinder slots. Just make sure you don't have too little tension either or the bolt can slip out of the slot on fast cock and then you will have cylinder overtravel. If your bolt is rising too soon and scoring your cylinder BEFORE the bolt is aligned with the lead in slots, that could be caused by a worn cylinder ratchet hand/pawl. That would cause your cylinder to not start turning until the worn hand/pawl engaged the ratchet. If the tip of your hand/pawl is worn, your cylinder will start turning late. That means the bolt will drop off your hammer cam before the cylinder is ready for the bolt to rise into the lead in grooves. To fix this there are two ways. 1. Get a new hand/pawl. 2. Take your old hand/pawl out and set it on a flat metal surface and taking a hammer and punch, carefully "peen" the hand/pawl to elongate it. Now the either new, or "peened" longer hand/pawl will start revolving the cylinder when it should instead of doing it late. If a bolt is dropping too late and "dinging/peening" the aftermost rear edge of the cylinder slots, you might need to file the leg on the bolt where it engages the cam on the hammer so that the bolt leg drops off the hammer cam earlier. As the hammer is cocked, the cam on the hammer engages the spring tempered leg on the bolt causing the rear leg of the bolt to rise which causes the teeter totter effect which unlocks the bolt from the cylinder. If that hammer cam is worn, it will cause your bolt leg to drop off the cam too early. If your hammer cam is fine but the bolt leg is worn it can cause the bolt leg to drop off the cam too early. And if your bolt leg drops off the cam too late, then you need to file the bolt leg so it drops earlier. Here is what I do. I inspect the hammer cam. If it is okay then the problem is the bolt. Next I inspect the bolt, if the leg appears okay, it is possible that the leg has just lost a little spring tension where it pushes up against the hammer cam. If I am thinking I am going to have to replace the bolt because the leg is worn out anyway, before I do that, I will VERY CAREFULLY (because it is a tempered spring and will break very very easily) try to spread the bolt legs apart just a little so I re-new and increase the tension of the bolt leg against the hammer cam. If that works then great, otherwise it is time for a new bolt. It's a good idea to have a few extra bolts, bolt/trigger springs, and hand/pawls in your spare parts kit when you go shooting. Also get yourself a good set of NON tapered, counter bored, screwdrivers so you don't mess up the screw threads. And get a little kit of fine needle files too. Also known as Jeweler files. Get a fine filing stone too. The stone will take off less metal then the files and is good for careful tweaking of parts for timing. A little 220, 400 and 600 grit sandpaper and some small wooden blocks to wrap it around is good too. Even some of the ladies emory boards for filing their nails work for fine tuning timing too. The idea is to always take off less than more and then try it. You can always take off more metal but it is hard to add to once removed. I hope this helped you understand correct revolver timing and how to fix some problems with that timing. If you have any other problems I didn't cover, let me know and I will try to help you figure those out. Last edited by Bill Akins; January 20, 2011 at 08:46 PM.