Hello and welcome back to another edition of The Rimfire Report. In this ongoing series we discover, review, and discuss anything and everything surrounding the rimfire firearm world. With the pressures surrounding COVID-19 somewhat subsiding and the turn of the season from frigid cold to blazing hot summer, I figured I’d try some ammunition testing. Specifically, is your 22LR pocket pistol ammunition waterproof? So let’s crack open an ice-cold juice and get to the testing.

The Rimfire Report: Sun’s Out Trunks Out! Is your 22LR Pocket Pistol Ammo Waterproof?

I decided to see how reliable a 22LR pocket pistol would be if carried in conditions surrounding common summer water activities. The most common of these would be a visit to the beach, kayaking and or canoeing, and finally a leisurely dip in the pool. I set out to find whether or not your rimfire pistol could be relied upon when the ammunition you carried was submerged in each of these mediums.

Testing Ammunition

For the experiment, I used three types of ammunition. First, some common Monarch 36-grain CPHP. This ammunition isn’t always reliable in every firearm but I have found it to work quite well in my Ruger LCP II which is the gun I used for the entirety of the test.

Second, I used some CCI Mini-Mag Varmint 36-grain CPHP. This ammunition is specifically designed for varmint hunting with a high velocity and lighter hollow-point bullet. I have also found this ammunition to be quite reliable in all my 22LR firearms.

Finally, the last ammunition I used for the test was some CCI Velocitor 40-grain CPHP. This ammunition boasts the highest velocity of the ammunition I used and would be the only one out of the three I would choose to carry in a 22LR pocket pistol – even before the test.

I had initially intended to test some CCI Stinger ammunition instead of the Monarch but due to the situation surrounding the pandemic, I was not able to secure any Stingers ahead of time.

Testing Mediums

I used three test mediums to simulate the different environments that your ammo would be submerged in. For each test liquid, I submerged 30 rounds of each ammunition and left them first in open glasses for about 4 hours. I then moved the ammunition from the glasses into sealed plastic bags and took them with me on some errands for an additional 4 hours where they were subjected to a moderate amount of jostling while inside the liquid.

The first 90 rounds were submerged in regular tap water which I used as a substitute for the creek, lake, or river water. I didn’t feel that going to an actual river or creek would make much of a difference. The point here was to basically simulate the ammunition being submerged in freshwater environments.

The second set of 90 rounds was submerged in a homemade solution of salt and water to simulate seawater. According to this website, seawater has a concentration of 35ppt (parts per thousand) of salt to the water. I used 35 grams of salt combined with an additional 965 grams of water to create the solution. Real seawater has other minerals in it but I felt this was an adequate substitute.

Finally, I used the swimming pool chlorine tablets to create what was essentially swimming pool water. By creating a pH of 7.6 in the water I essentially simulated a home swimming pool with a pH on the upper end of the recommended scale.

An additional 60 rounds of each ammunition were left untampered with for a control test.

Results

The ammunition was tested right after it was drained and loaded into magazines. All the ammunition was shot in one session. I posted a full demonstration on YouTube which will be featured at the end of this article but I’ll summarize the results and my conclusions here.

Monarch 36-Grain CPHP Results

• Control – 0 Failures
• Freshwater – 0 Failures
• Seawater – 1 Failure to Fire
• Swimming Pool Water – 3 Failures to Fire

CCI Mini-Mag Varmint 36-Grain CPHP Results

• Control – 0 Failures
• Freshwater – 2 Failures to Eject, 1 failure to fire*
• Saltwater – 1 Squib, 1 failure to fire
• Swimming Pool Water – 2 Failures to Eject, 1 Squib

*This round was rechambered and fired on the second strike

CCI Velocitor 40-Grain CPHP Results

• Control – 0 Failures
• Freshwater – 0 Failures
• Saltwater – 0 Failures
• Swimming Pool Water – 1 Jam/Misfeed (round got hung up on the feed ramp)

Conclusions

In total, I fired 360 rounds of ammunition 180 rounds of which were control tests. 90 of those control rounds were fired before the test and an additional 90 were fired after the test. To be quite honest I was surprised at the results, especially the fact that the CCI Mini-Mags did far worse than the cheap bulk Monarch ammunition.

As it stands I think the results give us a good indication of exactly where it might be safe to carry your rimfire ammunition in a pocket carry situation. For fresh and saltwater, it seems like if you carry high-quality ammunition with good sealing then you should be fine. However, my data seems to indicate that you should avoid the pool at all costs if you’re concealed carrying a rimfire pocket pistol.

I am not quite sure why the chlorine had the most drastic effect on the ammunitions but if I had to guess, the chlorine might be dissolving the wax coatings on the outside of the casings which allowed water to enter the casing and render the powder and primer useless (in some cases just the powder).

Once again, I have to come to the conclusion that you should avoid carrying a 22LR pistol unless it’s absolutely necessary. In the summer, clothing and concealment is often the biggest issue and pocket pistols end up being the best options sometimes. Given that the CCI Velocitor malfunction happened at the end of my shooting session and it wasn’t ammunition related, I think that Velocitors would be the best option – at least until I get time to test CCI Stingers.

Thanks again for stopping by to read The Rimfire Report, please let me know your thoughts and comments down below and we’ll see you again next time!

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