Benjamin 'Pump Assist' history

[Daysailer]

Here is a some history I have found about the Pump Assist modification on the Benjamin 397/392 a few years ago.

Original site offering this modification;
http://airchanics.com/PumpAssist.html


Then some history how it came to be marketed by an on line seller;
https://www.pyramydair.com/blog/2007/08/benjamin-392397-thats-easy-to-pump/

https://www.pyramydair.com/blog/2007/11/the-pump-assist-benjamin-392-part-1/
https://www.pyramydair.com/blog/2016/12/pump-assist-benjamin-392-part-2/
https://www.pyramydair.com/blog/2007/11/the-pump-assist-benjamin-392-part-3/
https://www.pyramydair.com/blog/2007/12/the-pump-assist-benjamin-392-part-4/
https://www.pyramydair.com/blog/2008/01/the-pump-assist-benjamin-392-part-5/

Please note in part 3, that the factory warrantee goes away with this modification.
This means to me that this modification was not made by Crosman.

crawling off my soap box now...

[airgunandy]

Yes, not sure exactly what "PA" on a Benjamin rifle stands for, but I am positive it isn't Pump Assist.
My '08 392PA was harder to pump than any other pumper I had. I say was because I modded the valve to make it easier to pump The fragile looking Pump Assist linkage was only a band-aid. Changing the valve is the cure. The old Benjamin and Sheridan rifles (pre-Crosman) had two springs in the valve, Crosman tried to make it work with only one and now the guns are harder to pump.

[Daysailer]

Usually dont like to hy=jack a thread,... but since its mine...   Y knot...

AirgunAndy,  What did you specifically do to reduce the pumping effort on your 392 ?

The only reason I have not upgraded from my 1980, all original, 766, is the pumping effort of the Sheridan and Benjamins that I look at.  With Hobby 7.0 grain pellets I am getting 390-400fps on 2 pumps for indoor 10M practice,  485-495 on 3 pumps, 5 pumps = 587, and when I go for all of 7 pumps, 650-665... more power than I am getting out of my HW30S right now, time for another tune.

Shoulder issues from 33 years of wrestling with  telco construction activities have made me aware of this issue.  But I really want to 'finally' get my Sheridan, or at least a 177 Benji.  If there is a reasonable way to get a transition version, or even a new one to pump as easily as my Crosman 766,  I want to explore that option.

Tks....ds

edit,....PS, no disrespect intended toward the Benjamin,  just always leaned to the .20.

[Toolmaker]

 The secret to an easier pumping current Benji is all in the valve. The vintage Benji's and Sheridan's had 2 springs in the valve, a heavy one for the exhaust and a light one for the intake check valve. You can set up the valve in the current guns the same way. This is commonly called the isolated check valve mod or icv mod. I did this to my 397 and it does make a noticeable difference in pumping. You basically remove the valve from the gun, unscrew the valve halves, remove the spring, put in a short light spring on the intake check valve, drop in a washer that will sit on the step that is already machined in the valve, put the original spring on top of the washer (some people shorten the original spring by a few coils), screw the valve back together and reassemble the gun. It's really not hard to do at all.   

[airgunandy]

Daysailer, just like Toolmaker said, just add a spring and washer to the valve. I cut three coils off the original spring. The first 4 pumps are like pumping my Crosman 2200 (.22 cal version of the 2100, the successor of the 766).

If you want a really nice pumper look for a vintage rocker safety Sheridan. No need to mod the valve and the triggers are awesome on the old Streaks.

Another option you might check out are vintage Crosman pumpers. I have a late 40's .22 caliber Crosman 102 that is even easier to pump than the Sheridan or modded 392. Crosman's pumpers are generally easier to pump because the pump tubes are smaller.

[Daysailer]

TM,  Thanks for the explaination and description of the valve and trigger mods.
Seems very doable.

AGAndy,  Thanks for the comparason of the effort with my 766. Very helpful, My shoulder doesnt protest too much when pumping the 766.

Both,  with your help, I am again looking more seriously at the Benjamin/Sheridans.
So far,  ones from the mid 90's to pre '06 seem to be the most available ones used.
How far back do I need to look to find the better trigger and valve that would not need moding ?  (just in case I run into one )

Tks....ds

[airgunandy]

As for which vintage Sheridans to look for, I think pre-1990's is probably your best bet. The '90's was the transition era where Benjamin and Sheridan products morphed together and then got bought by Crosman. An early '90's rifle will have the old style valve, but I'm not sure of the triggers. Some say they aren't as nice as older rifles. Mid 90's is after the Crosman takeover and will no doubt have the current model valve and trigger. Just to be sure, look for a rocker safety or even a thumb safety. Thumbers are the oldest, from the late '40's to early '60's.

Check these links for more info on old Sheridans.
But be careful not to drool on the keyboard! 

http://ujays.net/sevolution.html

http://ujays.net/scseries.html

http://ujays.net/sc9series.html


Here's a little dope on the old Crosman 100 series too if you're interested....

http://www.network54.com/Forum/393389/thread/1204597302/Crosman+100+series.

[daveshoot]

I have an '81 Blue Streak and love it. I have the Mac1 steroid treatment done, but if it still holds air that's not mandatory. The C version with rocker safety (1990 and earlier) is the one to get if you want a .20 cal.

[daveshoot]

Here ya go. Don't know the seller but the rest is up to you.

http://www.network54.com/Forum/79574/thread/1286411838/F-S...Sheridan+blue+streak+with+rocker+safety

[Daysailer]

AGAndy
Thanks for the links to the evolution of the Sheridans
Very helpful.

Dave S.
Thanks for the comment about your  '81, and the link to the '75 on the yellow.
I spent last night waffeing about that one, and pulled the trigger on it this AM.

Now the waitin' fer the big brown truck.
ds