Gun powder questions

[FSJeeper]

I have 250 round s of meticulously loaded .308 with IMR 4064 powder loaded Jan 1st, 2016. Someone "moved" my bullet seating die so they never were finished until this weekend when I have a new set of dies.

Stored in a climate controlled cool dry place wrapped in aluminum foil in their trays for 5 months.

I am inclined to go ahead and load the bullets this weekend but thought I would check and see if gun powder stored in the open air for that period of time would go bad.

What are your thoughts?

 

[Kruff]

As you probably already know, gunpowder is hydroscopic, meaning that it will absorb moisture from the air.
Since you had them stored in a cool dry place and covered with aluminum foil (covered being the important part) I would say they are okay to load.

I did something similar with 5.56 rounds. I charged 100 with powder but got called away before I could finish them. I covered them with several plastic bags one on top of the other and put weight on them to keep the plastic against the case mouths.
I loaded them about 1 month later and they shot just fine.

 

[JohnnyFlake]

99.9% probability, they are fine!

You could finish up 8/10 of them, picked at random and try them at the range, or where ever, before finishing them all.

 

[ants]

99.9% good, but just to be smart...

JohnnyFlake has the right suggestion. Seat bullets in 5 or 10 and test at the range first.

We know you said "Stored in a climate controlled cool dry place wrapped in aluminum foil in their trays"
but just to be on the safe side (I would if they were mine! ) I would test a few first.
250 meticulously prepped and charged 308 Win are too valuable, that's a lot of time invested.
If the test rounds shoot well then you can seat the rest with confidence.

Sounds troublesome to go to the range with just 5 or 10 test rounds.
But to confirm 240 rounds you can shoot with confidence, it is definitely worth it.