Benjamin air rifle

Sweet. Is that a .22?

Looks like a 342 with the tootsie roll handle. Mac1 can probly help you out.

http://www.mac1airgun.com/steroidbenjaminsstreaks.html

http://www.mac1airgun.com/rebuildpartstechniques.html

its most likely a 312 or a 317...dunno who painted the black caps on the end of the tootsie roll pump handle , but it doesnt look that bad actually.... you get on ebay and find a pump cup - but they want around $12 for a rubber plunger cup , i get em in the 5 pk from mccaster-karr (u can darn near find any part you'll ever need there)....but usually ,that and some lube usually fixes it enough -- and , those just unscrew where the pumparm connects (others we have to drive out pins).... ---- make sure theres nothing stuck in the barrel by opening the bolt all the way and looking thru the muzzle for light (of course, you'll have hold the open bolt area up TO the light) because ive made this mistake here lately...... i fix of these things for folks here around ft.w / dallas area (n.texas) as a hobby anymore ..... it used to be a bigger thing , but whatever.... i'll help you all i can. - paul. north texas airgun repair on fb. (formerly rane air)... cheers , man - ps: great bunch of guys here , bro... 

Just finished a total rebuilding of my Blue Streak .20 a few months ago. Have owned it since the 70's never failed.

....if you need metal parts - you'll need to to call tim, or someone at mac1 airguns in calif.....that's where i get my metal parts when i dont have spares......trust me he'll probably have you need there.....and honestly , maybe you better send it to him and wait the 4-5 months to get it back ( but mac1 IS the best for older american airguns ) ..... call him , find ouit what he would charge ( dont ask too much about the turn around time ) .....because i charge $75-80 for complete rebuild of all rubber parts....you need metal parts, too sounds like.... those 312 / 317 ones are way more accurate than the 392's ive tried lately , even tho these newer ones are bigger and more powerful. - paul. 

...,.the model number will be either on the breech area , or on the the back end cap , at the back of that whole brass tube the gun is built inside... - paul.

I’m pretty sure you have either the 312 or 317 Benjamin Franklin. There is a you tube video of one where the guy did a cut away to show how the valve system works. They can be rebuilt and are fun guns. I just did a 312 that I have had for years.