Benjamin 312 pump cup ajustment
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Benjamin 312 pump cup ajustment
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Topic: Benjamin 312 pump cup ajustment (Read 4181 times))
Jspeak
Shooter
Posts: 26
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Real Name: Joey
Re: Benjamin 312 pump cup ajustment
«
Reply #20 on:
June 04, 2017, 07:48:34 PM »
What is behind the vent hole is just a cup holder and cup that's it only maybe 1/2 or 9/16 total length.
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Warrior, AL
Jspeak
Shooter
Posts: 26
yes
Real Name: Joey
Re: Benjamin 312 pump cup ajustment
«
Reply #21 on:
June 04, 2017, 07:59:31 PM »
Think I am probably going to get the pump rod off ebay with the felt oilers on either end. Thanks for all of the input.
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Warrior, AL
Rob112o
Duce Duce all day every day.
GTA Senior Contributor
Posts: 2407
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Real Name: Rob
Re: Benjamin 312 pump cup ajustment
«
Reply #22 on:
June 04, 2017, 08:00:11 PM »
It's definitely not the original. That's why you can't get it to just the right area. As you can see in my one pic my, cup fully passes the air hole. Can't tell if yours does or not with the pic you provided. You can either get an original or try and get one from a vendor or have someone make one. Another option is to drill hole longer so it gets a full gasp of air.
«
Last Edit: June 04, 2017, 08:01:58 PM by Rob112o
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Nashville, TN
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Jspeak
Shooter
Posts: 26
yes
Real Name: Joey
Re: Benjamin 312 pump cup ajustment
«
Reply #23 on:
June 04, 2017, 08:19:28 PM »
You can't really tell in the pic but in that position th cup is clearing the air hole. Here's how she looks after the brass black.
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Warrior, AL
Hoosier Daddy
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Real Name: Scott
Re: Benjamin 312 pump cup ajustment
«
Reply #24 on:
June 04, 2017, 09:14:34 PM »
That is one of the first, if not only, photo I have seen of the results from Brass Black.
Thank you!
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Kendallville, IN
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JimQwerty123
always said ...
"Shoot safe and have fun!"
Jspeak
Shooter
Posts: 26
yes
Real Name: Joey
Re: Benjamin 312 pump cup ajustment
«
Reply #25 on:
June 11, 2017, 10:04:51 PM »
Just to update progress, I was having trouble seeing how different pump rod would help when it seemed stroke was the problem. I found that with the pump all the way open I could push the piston open with my finger another 3/16 to 1/4. The stroke length that I was loosing seems to be coming from slack in the rivet connection in the pump arm. I believe repairing that connection to take out the slack will be the solution. Thanks again for all the input.
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Warrior, AL
Hoosier Daddy
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Real Name: Scott
Re: Benjamin 312 pump cup ajustment
«
Reply #26 on:
June 12, 2017, 07:08:44 AM »
Ah-Haaa!
That'll certainly do it. Hopefully it's just the pin worn and not the holes in the linkage wallowed out.
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Kendallville, IN
ON THE GTA MAP!
JimQwerty123
always said ...
"Shoot safe and have fun!"
Rob112o
Duce Duce all day every day.
GTA Senior Contributor
Posts: 2407
yes
Real Name: Rob
Re: Benjamin 312 pump cup ajustment
«
Reply #27 on:
June 12, 2017, 02:32:13 PM »
Like Scott said good chance the pin is bent at the piston guide off of the link lever (from over pumpers). You shouldn't need to think if it was the rivet which you are describing. It should easily visible the added movement. It can be the link lever is bored out of the rivet is worn. My guess is it's going to be the link lever has been bored out by the rivet. Caused by over pumping and no lube being out there over years.
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Nashville, TN
74Ben342(Batman)
66Ben312(Robin)
61Ben317
Crosman 1322(Pester)
Challenger Plainsman P22
FOR SALE:
04 C9A (Streak) .20Cal
Steyr LP1 early Co2
Morini 162E
61 Benji 317
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Benjamin 312 pump cup ajustment