DIY: Trigger Reset and Overtravel

Update June 14, 2016: I just installed a Volquartsen trigger blade in this 10/22. It’s a better solution in every way for about $25, and I no longer recommend this DIY method. Skip one pizza and six-pack and spring for the trigger upgrade. Reviewed here: Volquartsen Target Trigger

When you say “10/22 trigger job,” most people think about lightening and shortening the pull required to release the hammer. I find that long overtravel and a scratchy reset are equally if not more annoying than a heavy trigger. I can finesse the trigger press, but in releasing the trigger for the reset we are wholly dependent on the trigger mechanism to do its thing.

The Kidd single-stage trigger I reviewed got my mental gears turning (always a sign of potential trouble). How can I get an ice-smooth reset and shorten the overtravel to quicken the reset and make it more positive? One of my favorite target 10/22s is my DIY mule – the one I use for experimenting on OEM parts. After dinner I headed for the basement workbench.

I started with this excellent video by Brimstone Gunsmithing (http://brimstonegunsmithing.com/) about polishing the sear and disconnector:

My next 10/22 will get a Brimstone Tier 1 trigger job. Tonight I put a mirror finish on the sear’s rear end and the edge of the disconnector hook, wet-sanding with 600-800-1000-2000 grits. It doesn’t look exactly like the one in the video, but it’s close. The sear has a very slight radius, really just a softening of the lower half of the rear surface but with plenty of meat for the disconnector to hold onto. The lower surface is flat with a sharp corner and positively holds the disconnector. I could probably put more of a radius on the sear and try a lighter return spring, but it’s good enough for now. If you give it too much of a curve, the hook on the disconnector can’t get a grip on the bottom of the sear and pulling the trigger will just make it slip off, if it resets at all. As the video says, the friction between the disconnector and sear may force using a heavier trigger return spring than you would like. Now it’s totally smooth.

The second part, reducing overtravel, was more complicated. The trigger went all the way back to the guard, making it seem like hours before it would reset. The usual fix for overtravel is to drill and tap the trigger or the trigger guard to install a set screw that stops the trigger. I wanted to do something totally non-invasive and completely reversible. Rather than stopping the trigger, how about stopping the trigger return plunger?

I cut a .080″ length of 3/32″ brass rod, squared up and deburred the ends, and installed it in the rear of the trigger return spring, with a bit of bearing grease to hold it in place. Then I installed the trigger assembly. The trigger seemed to move about as much as the Kidd. But when I installed the hammer, and tried to fire, it would not release – there wasn’t enough trigger movement to pull the sear out the hammer notch. Thus began the first of about twelve rounds of fitting. I took it all apart and wet-sanded the brass button on some 600 grit paper, shortening it to .076″ – no go… .073″  – no go… Each round it became more difficult to hold the button square to the paper. Finally, at a length of .062″ (about 1/16″), the trigger moved far enough back to trip the hammer. It also allowed the sear and disconnector to reset.

The good camera isn’t available tonight, but here is a photo of the finished stop button:

Button 150105And here are brief videos of the trigger pull and reset, showing how much they have been shortened. It is now a very nice trigger and I think it will help raise scores in rapid-fire stages and Steel Challenge. I’ll make a proper how-to video in a few days after testing it at the range. Some people might call this a Bubba job, but I wouldn’t. No changes were made to the OEM parts and the stop can be removed easily.

UPDATE Jan 30, 2015: I found that sometimes, although rarely, the trigger would not pull far enough to release the hammer, particularly if I made a point of pulling the trigger straight back. Squeezing the trigger with slight sideways pressure would cure it. I believe that the 3/32″ diameter spacer was small enough to rotate  or cant in the plunger hole, which effectively made it thicker than designed. It occurred because in shooting position, the back of the hole is at the top, and gravity plus vibration from recoil made the spacer move. This morning I made a new spacer from 1/8″ brass rod. This is wide enough to lie flat in the hole and makes a better base for the plunger spring to seat against.

There is one important difference: Typical of blind holes made with a drill, the end of the plunger hole is tapered. The wider spacer does not seat as deeply in the hole as the 3/32″ one, so I had to reduce the thickness to .051″. I also rounded and polished the trailing edge of the plunger body so it would not bind on the spring or against the hole.

After bench testing and a lot of dry fire, I believe the trigger is now absolutely reliable. Once the weather improves, I’ll range test it with a hundred or so rounds.

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One Response to DIY: Trigger Reset and Overtravel

  1. StikkershokK says:

    I like the spring stop button idea. I will test it out, but will probably replace the trigger spring plunger, turning one with a much longer “tail” to replace the 2 piece button system. Thanks for the idea, I was about to try just a zip tie on the back of the trigger guard. 🙂 (I have also ground down the plunger a mm or 2, to remove a little spring tension)

    Like

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