Tuesday, March 26, 2013

A very useful tip for .22LR snap caps

Like most careful shooters, I'm wary of dry-firing any .22LR (or other rimfire cartridge) firearms.  When the gun's unloaded, the firing pin can impact the side of the chamber, leading to indentations in the metal and/or a broken firing pin.  These illustrations of the rear face of a pistol chamber and a rimfire revolver cylinder, courtesy of Calguns forum user Chaos47, show such indentations.

To get around this problem, it's recommended to use so-called 'snap caps' (dummy rounds that cushion the blow of the firing pin, preventing damage to it or to the cylinder or chamber wall - as an example, these Pachmayr .22LR snap caps are offered by Midway.)  Unfortunately, these don't last all that long in rimfire calibers - my experience is that they need to be replaced after between 10 and 20 uses - and as a result, it becomes expensive and inconvenient to continually replace them.

That's why an e-mail hint today caught my attention.  The correspondent (to an e-mail list of which I'm a member) pointed out that #4 drywall anchors, such as this one (also known as wall plugs or dowels outside the USA) are almost exactly the same size as .22LR snap caps, and function just as well as the latter in revolvers, as well as in those pistols or rifles where they can easily be inserted into the chamber (which isn't always the case, unfortunately).  They even fit beneath the extractors in many such weapons, allowing them to be easily removed.

I was surprised to read this, but a quick Internet search revealed several threads on gun forums that confirmed the information was valid.  This picture from user Geezer on the Carolina Shooters Club forums illustrates how they fit into a revolver cylinder.

Intrigued, I went down to a local hardware store and picked up a box of 100 #4 drywall anchors (identical to that illustrated in the link above) for under $4.  Sure enough, they fit and function just fine in my rimfire firearms.  I don't know how long one of them will last, but so far one's taken six firing pin strikes on the same portion of its rim without breaking or completely flattening.  Given that they can be rotated in the chamber, bringing a new portion of the rim beneath the firing pin, it looks like they may last quite a bit longer than conventional snap caps - and at a cost of less than 4c apiece, what's not to like?

That's your shooter's money-saving tip for the day!



John Peddie (Toronto) said...

The claws on the extractor are usually the death of plastic snap caps.

I spent the extra money and bought aluminum ones for my shotguns.

They last a lot longer and $ ahead in the long run.

Carteach said...

Hmm... this is neat!

I'll buy a box today, and try them. If it works as described, I'll blog it with photos for everyone as well.

Great idea. Thank you Sir!

Jennifer said...

Yep. That's what we use.

Anonymous said...

For the really cheapo's among us, make your own snap caps. Take a deprimed cartridge, fill the primer pocket with silicon sealant, add a bullet ( no powder of course), let dry for 24 hours and there you go ..
Mine last several hundred strikes before having to replace the sealant. Works for both rifle and pistol rounds.

Anonymous said...

Greettings from finnland!

That phenomen of deformed chamber.. It is wierd custom of western manufacturer to make firing pin to strike over the case rim. Actually it should hit inside, well clear of the case base bulge.
There was article in magazine in finnland where author modified firing pin to strike right. Speed variation decreaced and accuracy increased depending ammunition 50 % (best case..) He also tried double striker but it was not worth of effort.
I myself have modified my anszhults in some extent. Striker is constructed so that i can't be made optimal without gunnsmith..

Janne Turtiainen

ps. clean my spelling.. if You like.. :-)

D Monkey said...

Your spelling and grammar rival the majority of the American public. You should be proud. I'll re-write your post below to fix the mistakes, but really, you're exceptional:

Ah, the phenomenon of the deformed chamber... it is a strange custom of western manufacturers to make the firing pin in such a way that it strikes over the case rim. In actuality it should hit inside the case rim, well clear of the case base bulge.
There was article in a magazine in finnland where author modified ths firing pin to strike correctly. Their speed variation decreased while accuracy was increased depending on the ammunition by a deviation of 50 % in the best case scenario. He also tried adding a double striker but it was not worth thd effort.
I have modified my anszhults to some extent, but ths striker is constructed in such a way that it can't be optimized without the help of a gunsmith.

Janne Turtiainen

ps. Please clean my spelling... if you would. :-)

-Thanks for the info, you're a wonderful person.