I set up to shoot today, but my Diana 350 magnum would not cock. The barrel pulls down to 90 degrees to the receiver (right angle), but goes no further (and obviously won't "click" in the cocked position because it needs to go a little further for that). I had removed the stock a while back to oil all the exposed metal (to prevent rust), but no other disassembly than that. Just the three screws to release the stock, and then back on after oiling. Did I bump something? Did some pin fall out that I didn't see? It all looks pretty straight forward, but obviously something isn't right now. (And I'm not saying taking the stock off caused the problem, but nothing else has been done). I did see some pins protruding from the trigger assembly, but they were never removed. Could one of those have been pushed in or out to the "wrong" position by accident while wiping everything down with the oiling rag? Hopefully something simple that somebody out there has seen before. Thanks!
Diana 350 won't cock
- Thread starter sammich
- Start date
I would first try backing off both trigger adjustment two turns.It sounds like the shoe is not coming down far enough to let the piston slide to go back far enough?
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Check the two forward attachment screws. These can be over tightened or bury themselves in the wood too far and hinder the cocking lever. Just back them off a bit and see if you can cock the rifle. If that’s the issue, you’ll need to either shorten the screws or add washers. I would also look up how to harden the wood in the screw hole itself with super glue to help prevent further erosion of material.
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Sorry about the delay with this reply. Been busy and limited computer access. Anyhow, it has a T-05 trigger, so just the one screw (which I've never touched), and I tried every possibility of screw tightness / looseness on the stock. I can see in the slot during cocking, and nothing is binding. It makes no sense. I did nothing but wipe down the outside of the spring housing with one of those gun oil rags. Nothing was dropped that I could see. When attempting to cock, it feels like it is coming up against hard plastic or rubber (in other words, not like solid metal on metal). I saw a "ding" on the forward portion of the trigger (see photo), but that trigger assembly is up against solid wood and plastic, so that must have gotten there at the factory during assembly (I'm assuming). I see no way anything can get in there to do that during normal operation. The spring compresses fine, but nothing locks in the cocked position, plus it feels like it bumps up against something, as mentioned earlier. I don't remember how far past 90 degrees it normally goes to cock, but it stops now right at 90 degrees. 
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Will it cock when out of the stock? Link below is to a great write up on the T05 trigger. Might be something there to help you.
Diana T05 trigger (and clones) re-assembly with pictures - Airguns & Guns Forum
Diana T05 trigger (and clones) re-assembly with pictures, Air guns, Airgun Forum
www.gatewaytoairguns.org
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I'll download those trigger instructions. I'm not sure I'd do anything to it, though (it's "good enough" as is, unless, of course, that's whre the problem lies).
As far as anything falling into the gun, nothing slides out or rattles, and the only place to get in is where the power spring slot is, and I'm not going to mess with a big 'ol spring like that.
I haven't tried to cock it out of the stock. I'd need to find a vise or some way to hold it to do that. I guess that's the next step.
My "made in China" guns still work fine, though (and are more accurate than the Diana anyway.... sadly), but don't look as "pretty". I'll try to solve this as time allows, or find a competent springer smith to fix it. (send recommendations if you have any
Thanks for the suggestions.
As far as anything falling into the gun, nothing slides out or rattles, and the only place to get in is where the power spring slot is, and I'm not going to mess with a big 'ol spring like that.
I haven't tried to cock it out of the stock. I'd need to find a vise or some way to hold it to do that. I guess that's the next step.
My "made in China" guns still work fine, though (and are more accurate than the Diana anyway.... sadly), but don't look as "pretty". I'll try to solve this as time allows, or find a competent springer smith to fix it. (send recommendations if you have any
Thanks for the suggestions.
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Ok, I went over that trigger assembly post again. Sounds like my issue is in the trigger reset or latch plate. It speaks of resetting whether in the gun or out of it. Maybe that needs to be done even if nothing was done to the trigger. I don't know. The website it sends me to is in German. I speak some, but not enough to wade through. It also keeps referring to pictures, which aren't anywhere to be found (on the thread). Anyhow, partial information is basically no information.
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OK this is kind of of a pane in the ass?but take the cap off the back and take out the spring put cap back on then simulate the piston back and forth with a screw driver.Or if the barrel is still hooked up use that to simulate.It looks like a pretty nice gun?just hang in their.
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"cap off the back"... are you talking about the plastic one that covers the plastic safety switch (is there a small spring behind that)? Or are you talking about the back end of the gun to get at the main power spring (which requires special tools, I believe)?
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I believe he's talking about the main spring. Sometimes if a spring is installed that's too long it will prevent it from latching. In your case I believe it was working and you did not have it apart so I would rule that out unless the spring broke and is somehow preventing the piston from moving. You need to try and cock the gun out of the stock and see what happens.
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jccams is right,i still think ya need to take it apart?something could have broke and is in the way?
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Agreed. I just had a friends TX200 give him a fail to cock situation during a silhouette match. The bottom of the TbT spring guide broke.
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Finally back in country and had enough time to take this thing apart. Nothing broken that I could see, but I did notice (by accident while poking around!) that the latch plates were a little sticky and binding. They still worked, but not smoothly. They pop right out of the top of the trigger assembly, so no need to take that all apart (see photos). Cleaned and lubed everything I could get at, put it back together, and it works better now than before (smoother, quieter, and a little more power). Note that this is a T-05 trigger, not the T-06. Looking at schematics I see that the T-06 doesn't even have these latch plates (perhaps part of the reason for its advent in the first place?). Do I KNOW this was the problem? Nope. But if it happens again that will be the first thing I look at.
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