Benji SS Gas Piston Conversion

[ezman604]

No reason NOT to convert a Benjamin Super Streak to an NP, at least in my book.   I asked Wai (LongIslandArcher) about some SS conversions he had done for some friends. He said the results were GREAT and he would help me out if I wanted to do it. I love my Benjis and jumped at the chance to convert the SS. I have all the original parts in case I ever want to convert it back.
The RAM used is a Walther Falcon. The factory piston has an integrated tophat. This has to be drilled out for the piston to slide all the way in. Wai used masking tape to center the RAM inside the modified piston and to help lock it in place. The spring guide will have to be cut off to look like it is in my pictures. The end cap/tube cover also has to be modified to accept the end of the RAM and keep it centered.
If anyone is interested, Wai can possible help you out too. I chronied mine after assembling and got about 20fpe with CPUM rounds. I'll be shooting more to let the new Maccari seal set in. I hope to see the numbers go up some. Oh, that was with my .177 barrel. I just installed my newly shrouded (thanks again Aaron) .22 barrel and will be zeroing and paper punching with that arrangement. I'll re-chrony it later this week.
Here's a few pictures of the new parts as they get installed.
Thanks again Wai.
You da man!!!!  
Happy Shooting!!!!
Dave
 

[Rocker1]

Dave is that mounted  backwards?? or am i looking at it wrong?? thanks david

[ezman604]

That's the way Wai assembled it and shipped to me. Works great!!!!
 

[Rocker1]

Is the recoil any different than the xls, seems with all that weight slamming forward it would be worse??? thanks david

[ezman604]

Not really. May be because the piston has to have the intergrated tophat removed. And with the spring guide chopped, the total gun feels lighter. Recoil is much more managable and follow-through is better. I can hold on target after a shot better than with the spring.

[airiscool]

Nice Dave.

I'd make one suggestion to anyone contemplating doing the same ....don't use masking tape to sleeve the ram.

Based on over 30 years working with masking tapes around oils I can tell you that ALL masking tapes are a sponge of any type of lube - even if the lube is present in only slight amounts.

What happens is that any petroleum based lube will dissolve the tape's adhesive into a slimy mess (takes less oil to do that than you think). Then any pressure on the tape will make it unravel and it will migrate around inside the piston with the slamming action. If pieces of the tape eventually come out of the piston, gravity takes over and they could potentially get down into the trigger group, or at least caught/jammed between the piston and bore walls.

Bettter to sleeve the ram with pressed-on nylon or delrin sleeves instead.  

Paul.

[ezman604]

Excellent post Paul. I was actually thinking that when I pulled it from the piston. I immediately thought of the 1" nylon spacers I picked up at Lowe's to use in mounting the shroud for my QB57 project. I'll measure the inside diameter of the piston and pick up some nylon spacers to match, or as close as I can get. I can step drill the center hole out till it fits snugly on the piston cylinder.
Thanks again!!!!