When I open my 50 round MTM rifle shell cases a few days after reloading a batch, there is a strong smell of gun power. Obviously, the rifle cartridges are not sealed air tight around the primer or case openings. Over time, it seems that the powder would deteriorate. Should this be a concern? If so, I've heard someone say using fingernail polish around the primer and case opening to seal it air tight would work. Anyone have any experience with this?

38,

I dont think this is a concern. Smokeless powder take YEARS to deteriorate. As long as you are not leaking powder out the cases you are OK. If you are then something is deeply, deeply wrong with your setup.

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I hunt, not to kill, but in order not to have played golf.

I do not think you need to add any sealant to your ammunition unless you think it may be exposed to long periods of exposure to rain or submersion. MM