Tactical Handyman: S.T. Action Trainer Snap Cap Mod

Most modern firearms can be dry fired without risking parts breakage but that doesn’t mean it is good for them. That poor breech face and firing pin/striker gets beaten and battered every time you pull the trigger. A snap cap can go a long way toward cushioning the blow and it is best to use them during dry fire practice. Unfortunately, the clear plastic snap caps that have a spring dampened primer don’t feed well in semi-autos, the anodized aluminum ones get torn up by the extractor over time, and they are all expensive. The Tactical Handyman knows that there is a better way. The best snap caps are the ones you make yourself!

ST Action Pro Snap Cap Mod


This is going to be easy. We are starting with really good dummy rounds, the S.T. Action Trainer Dummy Rounds. These are great because they have real brass cases, are loaded with brightly colored fake bullets that completely fill the case, and they don’t cost much. When we are done with them, they will still be really good dummy rounds but they will also be snap caps. You will also need some RTV Silicone which you can find in the automotive section of your local hardware store, a toothpick, and a sharp knife.

Just to recap, you need:

  • Some S.T. Action Trainers
  • RTV Silicone
  • A toothpick
  • A sharp knife


I said this was going be easy and I wasn’t kidding. You should be able to do these in large batches.

  1. Fill the void in the “primer pocket” of the S.T. Action Trainer with RTV Silicone. It may help to use the toothpick to pack it into the pocket. Make sure you fill it to overflowing – we will trim the excess later.
  2. Allow the RTV Silicone to cure as long as the silicone’s manufacturer states.
  3. Trim the “primer pocket” to flush with the sharp knife.
  4. Dry fire with the peace of mind of knowing that your firing pin/striker is being gently cushioned by your DIY snap caps.
ST Action Pro Snap Cap Mod Series

This photo shows the progression from empty “primer pocket”, to overfilled, to trimmed.

Wrap Up

When you are done, you will have the best of all worlds – a great dummy round that is also a great snap cap. These can be used to train malfunctions on the range or to make your dry fire trainer safer for you and easier on your gun. Every shooter needs a supply of good snap caps.

You can get your S.T. Action Trainer Dummy Rounds at TacStrike.

2 Responses to Tactical Handyman: S.T. Action Trainer Snap Cap Mod

  1. Battle Systems LLC March 25, 2013 at 23:24 #

    Thanks for posting this, JTT. Great idea.


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