Turn an 880 into a SSP ?

[ray1377]

Anybody ever tried to see how many fps you can get with a 880 by turning it into a single stroke pumper?
Sorta like a 853.
Is this even possible?
Curious to hear if others have tried it.
Thanks
Ray

[ray1377]

Dang, 70 views and yet not one reply?

Ray

[cobalt327]

IIRC there were projects like that on one of the now-defunct 54 forums, don't recall exactly which one but it might have been the yellow. These guns were heavily modified. I'm not sure if the forum was archived before it went under, but if it's available for viewing, that's one place to look.
ETA- Found it- https://www.tapatalk.com/groups/yellow/index.php?sid=293538ceaf6e41df856761644383777b
Searched for "SSP"- https://www.tapatalk.com/groups/yellow/search.php?keywords=ssp&terms=all&author=&fid%5B%5D=79537&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

FWIW there's already a SSP close to what you proposed, the Daisy 840. It's not exactly like a SSP 880, but it has some similarities. It makes around 330 fps w/7.4 gr lead pellets, so no powerhouse. To make serious power, a lot of work would be required to reinforce the 880 pump arm and associated parts.

[Back_Roads]

 The 880 is already an awesome 3SP  Three Stroke Pneumatic 

[the fuse]

Save some work and pick up a used D 853. You will have a much better SSP than an 880 ever could be. Unless, of course, the work is half the fun. 

[Rob M]

the problem is actually swept volume , the .735 piston along with its less than 4 inch stroke is not enough to make an ssp , even with the smallest of valves.. One way to test it would be to stuff the valve with a rod to displace air , fire.. then add more stuffing to the valve and fire.. id be surprised of you even hit 200 fps in factory form

[bantam5s]

The 880 is already an awesome 3SP  Three Stroke Pneumatic 

Tell me about it.
I call my 880 with target rear sight the accuplinker.

[bhh]

I get 315 fps with one pump and a 7.0 gr Basic pellet in my big bore 880. Might be interesting to see what reducing the valve volume would do.

[Rob M]

I get 315 fps with one pump and a 7.0 gr Basic pellet in my big bore 880. Might be interesting to see what reducing the valve volume would do.

I thought of your build when this thread came up , your gun defies the rules completely

[bhh]

Yea, it's definitely not typical.   

Anyway, for comparison, today I shot a normal tuned 880 and one pump with 7gr Basic = 270 fps.
Then I tried my 717 pistol and it did 365fps  with the same pellet. It has the original seals and I bought this about 30 years ago.

[ray1377]

I get 315 fps with one pump and a 7.0 gr Basic pellet in my big bore 880. Might be interesting to see what reducing the valve volume would do.

Can someone please provide the "big bore" link?
I can't seem to find it.
Would love to read up on it.
And yes, isn't it strange how a tiny 717 pistol can push a pellet faster with one pump than a long barrel rifle?
It's all in the valve size I'm thinking.

Thanks
Ray

[bhh]

Start at the bottom of page 16 on this thread:

https://www.gatewaytoairguns.org/GTA/index.php?topic=113496.0

Let me know if the pictures don't show.

[ray1377]

Start at the bottom of page 16 on this thread:

https://www.gatewaytoairguns.org/GTA/index.php?topic=113496.0

Let me know if the pictures don't show.

No sir, sorry to say that no pictures are visible for me.


Thanks
Ray

[bhh]

I started out with a piece of .870 i.d. tubing.



I machined a sleeve to fit the original 880 tube inside the big tube for only the valve section. So stock valve size remained unchanged.



I did a little heating and beating to form the frame to fit the tube.



Then I made a new piston.



Results were that I got normal 10-pump power with 6 pumps, and it was still easy to pump.

Negative was that the cheap Daisy components couldn't take the increased stress and headspace increased quickly as the plastic parts wore out.

[ray1377]

I wonder if you had reduced valve space if the pressure would have built up higher with fewer pumps?
And when you say "heating and bending" you ain't kidding!!!
Thanks
Ray

[bhh]

I took a look at my 717 pistol and the pump tube diameter and length of stroke are about the same as my big bore 880.

Based on that, I'd guess that reducing the valve volume would get me close to the speed of a 717 with a single pump.

I don't think you're going to get there with the stock 880 bore and stroke.

A Daisy 880 is $35 at Wal-Mart. You know what to do...