How to tune airgun triggers

In this post, I’m going to show you how I tune my airgun triggers. Trigger tuning can be dangerous if it is not done carefully, so I discourage anyone from doing such an activity without proper tools and knowledge. Trigger tuning will most likely void your warranty. Today, I am going to perform a tune on my Umarex Fuel trigger. It is a decent trigger, but there is a bit of a gritty feel to it.

The first thing I do is remove the action from the stock. I place it on a surface where I’m not going to lose any components. Taking pictures along the way can help you figure out how to put everything back together.

Stock removed from action
Stock removed from action

Take careful note of where springs are located. Many times springs are under tension, so when you remove the pins, things can fly. I recommend placing your hand around the trigger assembly to prevent things from getting lost. Start with the lowest pin and work your way up. As components are removed, place them and their pins in order to keep track of where they go and how they are oriented. When you have finished disassembly, take another picture, it may help you later.

Components laid out in proper orientation for easy reassembly
Components laid out in proper orientation for easy reassembly

Now that your components are laid out, note the mating surfaces. Also note any surfaces which my have a spring sliding along them. These are the surfaces that will need to be smoothed out and polished. Here’s the surfaces I smoothed and polished in my Umarex Fuel:

Surfaces to be detailed are highlighted in red
Surfaces to be detailed are highlighted in red, be sure to click the picture for greater detail

Keep in mind, all I am trying to accomplish is to remove any machine or casting marks, and then polish to a near mirror finish. I want my airgun to be safe and reliable, so I take care not to remove too much material, or change any angles. Here’s what I mean by marks:

Note how rough this surface is. This leads to a rough trigger pull.
Note how rough this surface is. This leads to a rough trigger pull.

I use a couple of sharpening stones to take out the really rough stuff, starting with a medium stone, and finishing with a fine stone. Take your time, taking care to only smooth the surface and not grind it down or change its shape.

Use a sharpening stone to smooth out rough surfaces
Use a sharpening stone to smooth out rough surfaces

Notice that I did nothing to the safety. Next, use a Dremel with a polishing kit to bring the surface to a mirror-like finish.

A Dremel and polishing kit is used to perfect each surface
A Dremel and polishing kit is used to perfect each surface

Be sure you clean any trace of polishing compound from the components. All mating surfaces need to be lightly greased during reassembly. I used silicone grease. This time, start from the bottom up, finishing with the trigger. Refer to your photos to ensure proper placement of parts. Before placing the action in the stock, it is a good idea to inspect for rust and give a good cleaning.

If everything was done correctly, your trigger should be smoother and lighter. Now you have a good excuse to spend more time shooting, as it might take you a few shots to get used to the way your tuned trigger breaks.

For a little more discussion on the topic, check out my YouTube video on the subject:

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Author: admin

I've enjoyed shooting and hunting with airguns since my early teen years. For over ten years, I have shared my passion for airguns on this website.

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