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radar · Silver Status Member

Does anyone know why the Daisy 880 is more powerful than the 901?

It is rated a little lower on Daisy specs, and the 901 I have does chronograph about 10% lower velocity than my 880, for me.

The pump stroke I measured the same, and the valving and port to the chamber look to be identical. For an experiment (and I don't recommend to anyone that they modify anything) I JB Welded a thin washer, opened at one end, onto the valve striker to make it open further and sooner. That got me about 5% more velocity, but still not up to the 880 I have.

I like this design (same on both models) pretty easy to understand or repair. Smart engineering. Cheap, accurate, and fairly powerful. Way to go Dasiy.

DougInAZ · New Member

Replying to a dead thread may not generate a lot of interest, but with my recent experience with the 880 variants, old and new, I thought I'd give it a go and offer a few possibilities for the MV difference between the 880 and 901 and/or new and later 880 actions.

I recently bought a 'Made in China' 880 from someone that was obviously better at taking things apart than reassembling them. I replaced the seals and learned a few things along the way.

I offered to take a look at a friends kid's late 70s Daisy metal receiver 882, and had a good chance to see the design changes in the 880 type of action from the metal to the plastic version.

When Radar indicated that they were the same design, I wonder if they were the same down to the exact details of the piston face. One thing that I noticed in the new 880 is the obvious inclusion of a pressure limiter in the pump that was not present in the old 880. The pressure limiter is nothing more than a hole cast into the face of the piston. Since some of the air that was taken-in at the start of the pump stroke is trapped in the recess in the piston face, the pressure in the pressure chamber can never rise higher than the pressure in this small space. The old 880 design didn't have any such obvious void between the piston face and valve.

Even if the two guns Radar had were identical, there are other variables that could account for different MVs due to valve pressure. The pump stroke could be very slightly different between the two guns, allowing one gun to move more air per stroke than another. There's still another variable in the pump arm, and that's the compressed rubber spacer between the piston and the pump shaft. This spacer can compress during the pump stroke and if one is softer than another, then the pump stroke will shorten more in the later strokes and move less air into the storage chamber.

All in all, I wouldn't be surprised by a 10% difference for 10 pumps between designs that were exactly the same, but with different mileage on them. I wouldn't be surprised if even two newer samples showed that much variation.

I agree with Radar 100%. The Daisy design is a marvel of simplicity and that got even simpler and cheaper over the years with no loss of utility.

DougInAZ · New Member

When I said 882 above, I should have said 822, a .22 cal version of the 880 metal frame variant.

DavidSaunders · Veteran Member

@DougInAZ:
Thank you for bring this thread up again. The information is good.