I have had this gun from new its a mid eighties model and 12 gauge, never had a problem with it but now just the other day the safety goes Back on when you fire the first barrel and it happens quite often.
Any thoughts gentlemen. Thanks Steve!

I suggest that you remove the buttstock and take a look at the safety workings from the inside. Slide the safety switch from Off to On several times and you should see what holds the safety in the position that it's in. It's likely that a spring has weakened over time and now the safety does not remain in the position it was placed in due to recoil. You might be able to tighten a screw or, more likely in my opinion, replace a small spring and fix the problem. Good luck and let us know what you find.