I´ve found a 10 % of power loose in 2 Diana´s 350 after arround 5-6.000 rounds. I did not find this problem in my Diana´s 36 and 45. I asked Jim Maccari for a tune kit, but he does not produce springs for 350s.When I ask about this problem to Diana factory, they told me that it´s normal to expect a power decrease after that number of shots.
Question,
Should I put an original Diana spring in my 350, or there are available other spring/kits that are better ?. I don´t want to sacrifice power. Please, any data of email or webpage for the spring source will be wellcome.
Thanks Tony. Will you please give some additional data of Paul Watts and Blackpool Air Rifles ?. I´ve been informed that the V-Mach kits are of high quality. Maccari told me that he does produce springs for the 350.
Best wishes, Teótimo
can check with Paul Watts as he had some of Maccari's 350 springs...Blackpool Air Rifles in the U.K. might have a V-Mach Kit for it...
I am to buy a 350 also and would like to know if someone has a link to a good takedown manual for this gun.
Also, does it have a lot of preload, or is a 350 just something like a longer 34 model.
Yes, you cannot take it apart without a spring compressor.
The spring sticks about 4 inches out the back, so dont even think about disasembling the gun without a spring compressor (you can make one yourself easily though, all you need is 2 long wiretaps, and 2 blocks of wood)
Once you have that, you really dont need a take down manual.
-2 stock screws, 2 trigger screws > stock comes off.
-remove plastic safety cap, leave the plastic safety pin in there.
-dont remove the barrel, you can just detach the lever since it is hold in place by the stock, which is removed.
-put the barrel in the hole you drilled in the wooden block of the spring compressor.
-gently tighten spring compressor and remove the 2 pins holding the triggerblock.
-release spring compressor and out comes the trigger block, spring, and piston.
The parts plan for the 26 up to the 350 are basically the same. Chambers gun makers (UK) has all the plans on his website i think.
p.s: if you do remove the plastic safety thingy, you need to press down the iron plate thingy with a screwdriver in the triggerblock while the trigger is squeezed. Release and the plate thingy will stay down, otherwise you cannot slide the plastic safethingy back in.
You can either do that with the triggerblock removed, but also when the triggerblock is back in place. Dont pull the trigger untill plastic safety thingy is back in place, because the plate in the triggerblock will then snap back up and you will need to click it down again ...
Teotimo, my 350 did much the same. I did replace the spring with a original 350 spring but I made a proper fitting guide. The original guide is garbage IMO. There is to much tolerance between it and the spring, make the spring cant very bad. With the new guide (and seal) in place, I have about 5-6000 rounds through the gun and it's still going strong (22-23 ftbls) and the spring has no sign of canting. I'm also trying out a different spring that seems to be working out well but I need to make a proper fitted guide for it aswell before I make any other comments on it. Check the breech seal on the 350 aswell. Mine looked o.k but later found it wasn't sealing well.
Hi Doug,
It seems that you have good skills for dismantle an airgun. I don´t, and besides in my country there´s almost no Diana parts or tunning kits.
I decided to put in my 350 a tunning kit from Mr Steve Pope, who I believed has got good reputation for his V-Match tunning kits. I understood that at present there´s no a tunning kit for the 350; so S. Pope will prepare one for my gun.
Do you have any suggestion ??
I check the breech seals in all my airguns blowing from the bore and controlling the velocity in the chrony. Which would be the best way to confirm that they are OK ?
Teotimo, I noticed the firing cycle on my 350 was starting to become harsh. Knowing the piston seal was good, I replaced the breech seal as someone suggested here on this forum. That was the problem. Blowing threw the barrel doesn't give enough pressure to find leaks unless the seal is really bad. The breech seals are cheap. An automotive or hardware store should have a replacement if the original seal can not be had. I'm sure you'll love your 350 even more after the tune!!! Let me know how it turns out.