The other day I "found" 4 boxes of 20 gauge Hevi-13 shells (2008 vintage) that I'd set aside about a year ago, because the crimps were sunken and were leaking buffer. This was pretty extreme as the star crimp was concave!
I decided to give them a try, if for no other reason just to put some shells downrange through a prototype choke that I've been shooting with some of the new Federal Heavyweight shells. When I looked at the patterns, they were some of the best that I've shot with 20 gauge H-13 in at least 2 years.
To see if it was the choke or the shells, I installed the SSX and again, had better patterns than I've shot with that shells since the 2005 vintage shells.
I have no explanation for this. These shells look really bad and I suspect, from my prior conversations with HS, did not have a full load of shot, of buffer or a full load of either when they left their place. The sealant is barely on them and some have lost the sealant entirely.