New to me 140 and 1400

[goatman]

 Back story: When I was a kid/teenager I had a Crosman 760 Pump Master I used for many years (12) with my hunting cat. It was die-cast with the plastic stock and forearm. My best friend had two air rifles,both Daisy I think, something and a powerline 880. The 880 was all plastic and broke in half after a few months. He should have had a 760! Before that another childhood friend had a Benjamin 1100 his father gave him. What a gun! It took both of us together to pump it to 10!! I have always wanted one of those. Then I see in a pawn shop....

 A Crosman (Sears & Roebuck 126 19300) .22 cal air rifle from the pawn shop cheap. Seals are bad of course, won't pump up ( i can hear air escaping when pumping), bolt o-ring is there but worn. Seems in good shape otherwise. The old man behind the counter said he had one he used when he was a kid at home that "blew air in his face when he shot it". He said I could have it for free! When I got it I found it was a 140 with the safety on the side of the stock. No serial number anywhere I could see, only the model# on the breach cover. It was pretty dry inside and the bolt o-ring was gone. I oiled it in the usual spots and it pumped up and it held pressure! With no bolt o-ring it blows pretty bad. I found that the breach end cap screw was stripped. Both guns have been disassembled several times by what I saw outside and inside.
 So I thought since the two guns are almost identical that I could swap the bolt and end cap screw. It still blows a little, but it works. I have no pellets at this time to check it out.
 My question is this: What o-ring/upgrade kit will improve these two the most? I want to use this as a camping/survival gun to take game as well as varmit control. So I'm thinking it should be as powerful as it can get while still being durable and reliable for a long time. I would also like any advise on pump limits and use limitations to make it last as long as possible.

[Ckistner]

I sent you a PM in case you wanted manuals.

Ck