made an adjustable piston for the 880

[Rob M]

thats the most common mod.. What did you do with the bumper rubber thing

[Grampy ray]

Yea I would like how you rigged the washer on the pistion too.

[bhh]

thats the most common mod.. What did you do with the bumper rubber thing

I put a washer behind the piston so that the bumper has preload and is harder to compress. My reasoning is that it would mean more air going into the valve. I could be wrong, but the lever snaps shut with the slightest of pressure so I doubt it's hurting anything.




Here's a pic of the hammer spring spacer. I drilled the nut to sit on the trigger nub and then drilled one side to create a cup for the spring to sit in. Drill a little at a time until the trigger cocks. Edit: You'll need to sand/file/grind a little off the sides of the nut to get clearance for the stock.

[Rob M]

very nicely done simple mods.. Ive seen guys stack washers to replace the rubber bumber and get good results, but seems like ur mod is better

[bhh]

Thanks. Yea, nothing big - just little tweaks here and there and they eventually add up.

[Rob M]

drilling the TP sounds like the hardest part, very vital seal area ..

[Grampy ray]

Thanks for the pics ,the nut idea brilliant!

[bhh]

drilling the TP sounds like the hardest part, very vital seal area ..

It is tricky. You have to squinch your cheeks together tightly. I used a cordless hand drill and went slow and easy. I think I drilled it in a couple steps and with the barrel out.

Thanks for the pics ,the nut idea brilliant!

Thanks.

[Grampy ray]

Drill the transfer port Is scary to me. Thats why I have not done it yet.i read somewhere if you put pellet in breach above the port and drll it wont make a burr and help drilling too deep.to the other side.

[Rob M]

figured as much because the area still needs to be super smooth to maintain a seal.this short list seems like the new standard pwer mods.. My question is , can it keep up with the big tube pump for pump

[Grampy ray]

I was also thinking if I drill the tp bigger and the hole was not perfict round. I have a lot of steel sling shot ammo that I could use to remake a round seat. Just drop a ball that is big as the poppet a few light taps it should make a perfit seat..just a idea here thinking out loud.

[bhh]

Maybe stick a wood dowel in the "chamber" area to keep from hitting the other side and keep the burr at a minimum? I use a dental pick to smooth out the sharp edge from drilling.


No way will this keep up with the big bore pump for pump, BUT, the frame just can't handle the stress and actually stretches and increases head space in the big bore. However, the goal of the big bore was to reduce the number of pumps at normal power levels.

I really think this design is best suited for 10 pump/10+fpe with an occasional 13 pump/12 fpe shot for hunting.

...and experimenting.   

[bhh]

Here's some ideas for drilling the transfer port:

Build a simple jig. Note: I just whipped this out quickly to show the idea. I didn't take the time to make it accurate enough to use.



Or find a washer or something round to fit in the chamber. Note: Be sure it doesn't rotate if it's on the o-ring sealing surface. I'm going to use a wrap of tape.



This is actually a strap button for a guitar. It fits perfectly. Two wraps of masking tape on the od makes for a snug fit in the valve, and the id allows a few thou clearance for my .140 drill bit. Talk about luck. Lol

[bhh]

Note about the hammer spring spacer: You may need to sand/file/grind a little off the sides of the nut to get clearance for the stock.

[Rob M]

do you think more volume would get u 1000 fps with 7.9s?? also , do u think its even maxed out at 24 pumps?>

[avator]

Maybe I missed something but, why the nut under the hammer spring instead of a stiffer spring?

[bhh]

Maybe I missed something but, why the nut under the hammer spring instead of a stiffer spring?

The nut was laying there on my bench and a stiffer spring is at the hardware store. 

[avator]

Maybe I missed something but, why the nut under the hammer spring instead of a stiffer spring?

The nut was laying there on my bench and a stiffer spring is at the hardware store. 

LMBO... I was sitting here visualizing all the times I've messed with the Daisy 880 and for the life of me I couldn't get my head around this and what the shim would do that a stiffer spring wouldn't. I was in the process of going back thru the pages trying to find the answer when you responded.  Thanks

[bhh]

do you think more volume would get u 1000 fps with 7.9s?? also , do u think its even maxed out at 24 pumps?>

Likely so, but I don't think the rest of the parts can handle the strain for very long.  I pumped beyond 23 pumps and didn't gain anything. I took everything apart after my "record attempt" (Lol) and found the pin that holds the abutment to the valve was bent slightly from all the pressure. 

[bhh]

LMBO... I was sitting here visualizing all the times I've messed with the Daisy 880 and for the life of me I couldn't get my head around this and what the shim would do that a stiffer spring wouldn't. I was in the process of going back thru the pages trying to find the answer when you responded.  Thanks

Lol, yep, it was just easy, cheap, and available. How's the foam barrel shroud coming along?