I haven't managed to leave any of your lubes sitting around that long
Stumpie, so maybe that's a good sign of how well they work. Have you kept
any around long enough to get a feel for how it holds up compared to bore
butter and such?
As a test I left a load in my .50 New Englander for 11 months and four
patched balls in the block for the same period. These were in an unheated
closet in my attached garage that runs 45º to 80º depending on the season.
The load fired but struck about 4" high of the normal zero (Upper left in
the image). The group is offhand and all hit high. I loaded the patched
balls and after the second I wiped (normally I can get seven shots without
wiping). A couple of the recovered patches showed some tearing, but I think
that was the ones I was huffing down the fouled bore and was not from
deterioration from the lube attacking the cotton.
The group was not so hot (this is 50 yards) but it was in the interest of
seeing what might happen. The bore was fine, cleaned up well, and I detect
no problems from having left the charge in. I would say accuracy suffers,
loading ease suffers and it isn't a good practice. I load my blocks up
before leaving the house and usually cycle through them within a month. I'll
pop them out and wipe a bit of fresh lube on the patch if they hang around
longer than that.
I have some pre-lubed strips in a baggie that are three years old and they
work fine.