Snap Caps - Another Way





Introduction: Snap Caps - Another Way

About: I'm a retired field service tech with 33 years in the alarm industry. I have a variety of interests mostly keeping mind and hands busy.

Snap caps are "dummy" cartridges that allow a shooter to dry fire a weapon without damaging the firing pin. A number of current production guns are said to be safe to dry fire, I guess I'm kind of old school and try to have snap caps for all of my guns. They are handy if for no other reason than they allow one to release the tension on the firing mechanism while the gun is in storage. Commercial snap caps are available for most of the common cartridges out there. If you have a .30-06 or a .270 or a .45 Auto or a .223/5.56 NATO you'll not have any trouble getting snap caps for your guns. On the other hand if like me you shoot a number of wildcat cartridges and old military or old single shot cartridges your likely to have a difficult time finding anything and if you do it's likely custom made and expensive. So if it's going to be custom made why not be the custom maker in your own workshop. This method came about while I was doing some other custom work to create cases for an OAL gauge. So if you've come this far come along and see how I've made snap caps for an odd ball cartridge or two.

Step 1: A Little of What You'll Need

First you'll need an example of your chosen case - either new or fired. NO LIVE CARTRIDGES PLEASE!!!!!

A 1/4x20 tap and a #7 drill

A supply of 1/4x20 nylon bolts I get these at whichever big box hardware store I'm close to when I need them. I initially bought 2 packages of 2" bolts I've made 8 or 10 of these so far and I'm on my second bolt for this Inscrutable.

For tools, you'll need someway to hold the cases without distorting them while you drill out the primer pocket and thread it. You'll also need a tap wrench and your reloading equipment as you'll want to full length resize the case and seat a bullet in it to complete the cap.

You will also want some type of lubricant for the tap. I've used Tap Magic and Brownel's Do-Drill and really don't have a preference. I've been told that Tap Magic can cause rust, but since I make every effort to clean up any lubricant I use it hasn't been a problem.

Step 2: Drilling the Hole

I'm fortunate in that I have a Sherline lathe in my shop and that is what I use to do the drilling. The first picture shows the center drill set up to start the process and the second shows the #7 bit completing the hole

Step 3: Tap the New Hole

After completing the hole I use the tail stock mounted chuck to make sure the tap starts straight. I then remove the case and tap and complete the job of tapping by hand. I find that case brass tends to the hard side and recommend a good lubricant to do the tapping. I have found that it often helps to drill the hole a little larger than the standard tap drill size. With the 1/4x20 I've gone as large as 7/32 and still have enough thread to hold the bolt.

Step 4: Insert and Cut Off the Nylon Bolt

After the hole is threaded I turn the nylon bolt in about 5 turns and return the assembly to the lathe where I use a parting tool to cut the bolt off flush with the case head.

Step 5: Add a Bullet and Your Done

The picture shows the completed case still in the lathe chuck. The lead photo shows the completed 7.62x54R snap cap. I have found that the 1/4x20 size bolt works okay for cases with large primer pockets but I've been less than satisfied by the results with this size in small primer pockets and continue to experiment with those to determine a suitable size. More on that latter.



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    Look for some of those new no lead bullets. they are probably pink! also off color casings. I sometimes find tin colored ones. or have them chromed.

    I have one suggestion... I realize that the big white thing where the primer should be should be a big clue, but Murphy's Law says that there's someone that will be in a big hurry that will grab a live round, thinking it's the snap. You really need some other way to determine that it's a dummy round. Perhaps colored with permanent marker?

    3 replies

    I'm still looking for a good way to permanently color my dummy rounds. I find that permanent markers aren't quite so permanent when you cycle them through the gun a few times. I've been told but haven't tried it yet that if you boil and egg and then soak the cases in the water the brass will turn black. How permanent the color is I don't yet know. I've thought about cross drilling the cases just ahead of the web. In the final analysis it's up to the maker and user. When I find a way I'll add a step here and then it'll be up to the users to follow through. My own personal solution is to keep live rounds off the bench when I'm working on any gun. It prevents the oft stated "I was cleaning my gun and it went off. I've always worked on the theory that there are 2 kinds of gun owners those who had an AD and those that will have sooner or later. So far I've managed to put mine off and make every effort every day to do so. Be careful and enjoy the day.


    Like you said I have just drilled a hole in the case of all of my snap caps. That way you can see and feel that it is a snap cap not a live round. I like the idea of the threaded plastic bolt I will have to start using that.

    So far over the last couple of months of use the nylon has held up nicely and no firing pin damage that I can detect. I've practiced the rapid fire stage with my Mauser several times and they still look new.

    Thank you, All these little projects keep the hands and mind busy. Range was deep in snow and the road not plowed and the roads are keeping the cycles parked so it's off to the shop and make chip and stuff.