How old is this 20 ga shotgun ammo?

[PA32Mark]

Just picked up two cases of this Remington (Peters) 20 ga shotgun ammo, got it almost for free (garage sale kinda thing). The two cases were still sealed until I opened one up. From the boxes, it looks pretty old. Can any of you knowledgeable ammo folks put an approx manufacture date on it, based on the box markings? Think it is still safe to shoot? The only thing I shoot with my 20 ga is trap and skeet once in a very great while - for fun, not competitively, I kinda suck at it - would trying this for trap or skeet be a waste, since it is buckshot?

 

[JWT]

Don't want to use buckshot for trap or skeet. Trap clubs do not permit shot that large.

 

[USCS]

I'd say 1950's or 60's. I seem to remember seeing some of those in my father's gun cabinet, many years ago.

 

[drobs]

Are the shells paper or plastic.
I've had zero luck with old paper shells acquired 2nd hand. Usually they don't fire at all.

 

[TomADC]

Shells yellow or red? I still have 20 AA Winchester cases that are red=old.

 

[PA32Mark]

Yellow plastic shells. See picture. Anyone think there would be any interest in this from ammo collectors? I have one still un-opened case (500 round case), and the other 500 rd case was also un-opened when I got it, but I opened it up a couple of days ago to check it out.