I had 3 primers miss-fire during a hunt in 15 degree weather, during a snowfall in Missouri this winter. I killed my deer but the snow caused three failures. Would clear nail polish work in keeping primers dry. We all know that when hunting, under duress, in bad weather, things can happen so I'm looking for ways to protect my rifle & loads during such times. BTW, these were good, name brand primers. The failure was caused by moisture.

Are you going to coat it front and back?

I have a Knight Disc Elite and havn't had a water problem yet. I keep my spares in a zip-loc bag.

Ted, I will coat it anyway necessary, so long as it doesn't cause "fit" problems. I'm open for ideas. When I reloaded in the snow apparently I got moisture on the primer. If you've hunted in that environment, you know anything can happen. I just don't want a repeat performance. Thanks

Only testing will tell you if anything will improve the situation.

Dab a bit of enamel or epoxy paint on each end then drop them in a cup of water for 1/2 hour then see if the will ignite a stout load of powder.

Maybe you got the powder damp enough reloading in the snow?????????????

What were you using? Shotgun primers? I use the #11 on my Whites. That is what they are designed for, and the caps fit so tightly over the breach plug there is no way moisture can get inside. The extra caps are in a possible bag, and out of the weather.

I have to believe that clear fingernail polish or primer sealant either one would seal a 209 primer or similar, but the only way to know for certain, as has been mentioned, is to test a few of them.

Last year, I hunted in the cold rain in November around Thanksgiving in MN. It was like 40 and steady rain and mist. I use cci mag shotgun 209's and 110gr of blackhorn 209. It fired perfectly. I was worried and wanted to try it to see results. No hang fires or anything. Just went bang! When I got back to my brothers house and ripped it apart, I had a lot of water in my forearm. Like the others, all my stuff is packed in zip locks. I keep my primers with my license, wallet, and cell in a zip lock in my dry seal pocket in my browning jacket. The rest is stored in my double seal zip lock in my pack.

IF you are talking sidelock gun then you might try placing a 9mm or forty case over the primer/nipple and letting the hammer down on it.
Check to see what it takes to keep the hammer/cartridge case from touching the cap.

If it is an inline i have no idea.

209 primers are waterproof.

A lot depends on what type of primers IE #11, 209 or musket caps. the handling of any primer in the field I really believe starts with the proper capper to fit the type of rifle IE side lock, in line or break action.
Caps kept in a capper in a zip lock bag in a inside the jacket pocket or on a lanard around the neck seem to stay dry for me. even in a heavy down pour one can usally find a bit of a dryer spot to cap the rifle and not have wet fingers handling the caps.

al