Canadian Airgun Forum

I have run into a problem with my Benjamin .22 classic spring to nitro piston upgrade.
As you can see in this picture, the screw threads for the trigger assembly no longer line up correctly with the action after installing the nitro piston and end cap that came with the piston. Has anyone seen this before?

Any help would be great, thanks.

Yes saw that before. I flipped the spring holder 180°, re-drilled and re-tapped (M8 x 1.25) the hole in the correct position. You'll also have to shave the back of the spring holder to be able to fit the plastic cap.

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If everything's so lovely yeah, then why don't I, why don't I, why don't I, why don't I feel lovely?

Take a dremel tool and elongate the hole slightly. problem solved.

Your next problem will likely be fitting it back in the stock. You may have to remove a little of the stock material near the rear inletting. Again, takes 2 minutes with a dremel tool.

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When the 425-hp "street Hemi" version hit the street in 1965, it was akin to taking an M230 chain gun to an arcade shooting gallery
Peter

Ohhhh I guess that is the 'light modification' I saw someone write in regards to this project. Ok, I can do that.
Thanks boys.

Yes I think so.

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When the 425-hp "street Hemi" version hit the street in 1965, it was akin to taking an M230 chain gun to an arcade shooting gallery
Peter

I know the pix I posted of my no cost redneck method was frowned upon, but now you have a more complex problem and more work to fix it. I can lead a horse, bla bla...... Or maybe I should've explained the below with the pix:
Reason for your issue is the cross pin on the nitro guns is .100" fwd compared to the coil. My guess is they wanted to make the hole stronger but also minimize the odds of people just buying the parts like you did, which would hurt guns sales, and as we all know quarterly statements drive the world as we know it.
Fyi; if you elongate the hole so the screw can fit you net .100" stroke which should be worth ~2.5% free power.
Drawbacks are: The stock will no longer line up since the rear "nut" is also .1" aft, but usually no biggie, just some grinding on the stock should make it fit but know that the D shaped metal thingy is there for a reason so try your best to lock it in there, or shim so the trigger housing can be locked against the stock. Without that bracing against the stock it means the screws are having to take the brunt of that piston slam, aka reverse recoil, which btw will be worse with the nitro spring. Your scope will feel the effects of both the spring and lack of support to the stock.
Also, and this is important, be certain your nitro has preload on it, like at least a couple mm but more like 4 or more is better. If the gun would've sat with say 2-3mm prelode, but now minus that .1" it's got nadda or barely any, you risk breaking the nitro via pounding itself apart internally. If you've seen the insides, and I posted pix here somewhere, it'll make sense.
Lasty; your gun may not want to cock the piston that last .1", or may require excessive cocking force to do it. If you end up there and can't figure out how to fix it, lemme know: chevota at hotmail