OK, I have read off and on about these cocking problems with the side lever. You try to cock the rifle and just before it reaches the engagement point it "hits a metal wall" and will not go further. The bear trap mechanism does not allow you to return the lever so you pull back just enough to be able to press the bear trap latch and down it goes. If you are lucky you try it again and it snaps right past the binding point and you are back in business.

I have a 460 and it is hoplessly in that mode! except it hits the metal wall every time and simply will not cock at all!

Here are my three questions:

1) Does anyone know exactly what is going on? have been able to fix something like that and would be willing to share it?

2) I have done many tunes on breakbarrel rifles, have my BSquare compressor and am willing to do my own work. Is there any pictorial sites for the dismanteling of the Diana 460 or similar sidelever (you tube or whatever where you can see pictures?

3) I have searched everywhere online for a Parts Diagram for the 460 to no avail. Is there a parts diagram somewhere online or somewhere I can order it on paper?

THANKS

This has to have something to do with rough tolerances, burrs and imperfections in the new RWS rifles. I had the same exact problem with my 54 when it was new. It was worse from the beginning and slowly with time just seemed to go away. Now that I have over 2500 shots on her, it NEVER happens. The entire cocking mechanism is smooth as butter and so is the shot cycle and trigger, and I've never had the rifle tuned either, just naturally broken in to a ultra sweet and powerful howitzer.

I guess it must have something to do with RWS rifles being a little 'rough around the edges' when brand new and the metal to metal surfaces just need to smoothen out over time. I'm sure a tune would get your rifle to where mine is right now MUCH quicker and get rid of the stuck cocking problem.

When the piston rod goes into the trigger assembly there are two plates that the rod goes through.When the rod passes throught the rear plate drops down and catches the rod.If there are burrs or rough areas on these plates they won,t move back into their position when the rifle is fired therefore they will block the rod from passing through the next time you try to cock it.The only to solve this is to tear down the trigger and smooth the edges. If the rod is jammed against them too many times with great force it will create a bow in the plates and you.ll need to replace them.

There a parts diagram on Umerex,s website for the 460. it does,nt show you disassembly steps.

You can get the parts diagram at www.umarexusa.com

they need to be de-bured and polished then lubed with some molly burnished into the surface. it is also helpful if the guide is made with a close fit to the piston stem so the stem is absolutley not allowed to move off center. some of them have some play. my 52 is now perfect and i had problems cocking.

Hi Rick, A few weeks ago I bought a new 460 to tune, I knew about the breach seal and lock up spring problems and also that some had trigger problems that needed sorting out.
Out of the box it was a bit rough and the the trigger stopped engaging after a while, so I dismantled the gun completely and examined every part and I found the build quality exceptional.
I sorted out the seal by fitting a heavy duty PTFE 52 breach seal and a stronger lock up spring and sent the TO5 trigger back to the importers who have sent for a replacement for me, so for now I am using a TO1 but the anti bear trap will not engage because it is about 10mm short of where it clicks in. The anti bear trap mechanism is very simple but needs to go a mm or so past where it clicks in or it wont disengage.
When I get my TO5 back I hope this will be ok but I am prepared to take a couple of mm of if nessasery,I have even thought about removing the anti bear trap as a last resort.
I really like the 460 so I am not going to give up until I have got it right, I have now got some custom parts for it and it and it shoots very sweet even with the TO1.
Barry

that the new trigger will do the job. not all 460 guns have a problem with T05
triggers so it is probably an anomoly with your gun.

the alignment of the piston stem is important to proper functioning of a T05 trigger. check your piston stem to see if it has play or if it is off center.
a small amount of play seems ok but i have heard of some with gobs of play and that is not good i think.

When MZ tuned my 460, we had to send the gun in for the same problem. They had to replace the trigger. I would think about sending the gun back to Ummarex, has they admitted that they have had many trigger problems.

Dave@vabch

Thank you very much guys. I knew I could get some intelligent answers. Thanks especially for the diagram.

I will dismantle the gun in a couple of days and let you know what I find. I don't like shipping my guns out, so I will take some chances. But it was a lot of help.

Rick

The T05 trigger is on the Model 34. If the plates are the problem, why is it not evident in the Model 34?
Rob

it shares the same piston as the 34. my piston stem has absolutley no play in it. the piston on the 460 may have a manufacturing issue.

48/52/54 group. both the 460 and 48/52 et al have a sliding compression chamber. that creaes two areas where tolerances may be the issue. you have the sliding compression chamber inside the action tube (clearance) and the piston inside the sliding compression chamber (clearance). there is perhaps twice as much movement inside the tube while cocking. more potential for misalignment
of the piston stem as it enters the latch plates. it takes a very precise guide to control this and the diana guides are not that precise. metal guides may be the solution with a centering ring to make sure it is centered in the trigger group.

My 460 has had the problem, but not too severe (unless you are the guide!). It locked up a couple of times and broke a couple of guides other times. I went for a new piston and the problems went away, although I could really see nothing wrong with the old piston (but I don't have precision instruments to check it out).

exactly in the piston.