Air Gun Home :: View topic

The outdoorsman · Veteran Member

how do you mod an EB22 for power?

Alstone · Moderator & Site Supporter

I'm not to familiar with the Beeman EB 22 but you could try increasing the strength of the hammer spring (CS398), either by changing it or packing it out a little.

Other wise it's a matter of doing some work on the valve to get the gas through quicker, and probably some work on the ports and bolt.

Al

The outdoorsman · Veteran Member

Alstone · Moderator & Site Supporter

Sorry Outdoorsman I meant Benjamin, thinking of somthing else at the time. Embarassed

Al

AirGunEric · Site Admin

Too early in the morning for Al- 'Beeman', 'Benjamin' same sh!t, different day and all that, right?

Either way- Al's info is correct. Being a Co² gun (pistol) hammer weight, spring tension and valve modifications are the basic things that can be done to raise the power level without using custom parts.

If you look at the design of the EB22, it is the same basic layout as a Crosman 2240- so the same mods that will work, in principal, on a 2240 will also work on an EB22.

Crosman markets the newest EB22's as having "up to" 500fps- but versions in the 1990s stated they would shoot 425fps with .22 cal pellets- so it's probably somewhere in the middle of that out-of-the-box I would think.

Here are parts references:

If you look at the diagram at the "Exhaust Valve" assembly- the main valving control is going to be the valve stem assembly shown between part numbers CS400 and OR040- the picture doesn't show it- but that round part in the center of the stem will have holes in it- if they are expanded by drilling or sanding, more Co² will flow, allowing more muzzle energy. That being said- this can be overdone as well and too much flow will result in Co² being wasted- so if modifying this, do a little bit at a time and stop when acceptable result are accomplished- you can go too far.

Part number CS398 appears to be the hammer/main spring which if replaced with a stronger unit, will also hold the valve open longer, allowing for more gas flow- again this can be overdone allowing too much gas to flow and possible changing trigger characteristics (i.e. pull required to release the spring).

In the case of the EB22, hammer weight or spring modification (sear) won't likely have much real effect on output being more of a release-only setup- but with this design- a 'tuning knob' for the mainspring could be installed to adjust output level by changing the mainspring tension- but to allow more power- you still need to change the spring like mentioned above.

What's an EB22 capable of outputting? I have no idea- I'm sure there's a few more fps available to come out of it.