Diana 470th catastrophic failure

[kiraskillz]

hiya everyone, I was out at the farm about to sight my rifle in for 50m when i have a catastrophic failure of the hinge pin when the rifle was fired.

I ordered the hinge pin and replaced it, I gave everything a good look over and it all looked fine , then when I test fired the rifle, the hinge pin, pin, circlip and spring support all failed.


my question is, why did this happen the first place? and how can I stop it from happening a 3rd time?


   

[Sfttailrdr46]

That looks really bad did the rifle have excess oil in the compression chamber I have a D460 with several thousand pellets down  range. The failure looks like massive stress did the rifle diesel as it fired?

[kiraskillz]

It did make a louder report that normally, but I assumed it was from the pin snapping. the first time it snapped my brother in law was firing it so i don't know if it made a louder report when it fired.
 

[shootist]

Hi Chris, fortunately you were not hurt when it failed!!! Without having the gun and it's broken parts in front of me, I can only make a guess at what has happened to your gun. First, because I haven't heard of any other Diana 470 failures like yours, I'd have to guess it's an isolated incident. Second, metal failures DO happen. Sometimes you'll see a air bubble in the metal or some other visible defect leading to the failure. I would take a close look at all the parts with as strong of a magnifying glass as I could get my hands on. Make sure there isn't any other parts that are hurting including the compression tube. Hopefully the holes where the pin fits wasn't hurt to the point of needing replacement. Then go ahead, replace what needs replacing and put it back together and try it out. I don't remember if you said the gun was still under warranty or not. Although in this case, I might be wanting to do the repair myself unless the comp tube is shot. Then maybe contact Diana in Germany, not Umarex and send pictures of the parts first before letting them out of your possession. They may want to replace the gun. Good luck with it and please let us know how you make out and maybe even what has caused all this. Have a great day - Lee

[shootist]

Chris, unless they have changed their policy, I believe Diana's are warrantied for life. Lee

[kiraskillz]

Thanks, I'll see if I can get something sorted with the warranty, but i would still love to know why it failed and so hard.
 

[DanD]

That looks really bad did the rifle have excess oil in the compression chamber I have a D460 with several thousand pellets down  range. The failure looks like massive stress did the rifle diesel as it fired?

I had a brand new 460 T06 in .177 that did the same thing. Within the first hundred shots it detonated and snapped the cocking linkage. I figured this was from the force of the detonation pushing the piston and chamber backwards and the linkage was the weak link. I was so disappointed that I didn't even want to post about it. I just sent it back to Amazon and tried to forget about it.

[kiraskillz]

Thanks DanD, every puzzle piece helps.

[kiraskillz]

just talked to my brother in law, he said it sounded like a 22lr firing right before it broke. 

so i think it was extreme over pressure from dieseling.

[jus Tom]

I had a very similar "catastrophic failure" with my 460 while shooting indoors this past winter, it was quite loud, like a .223 firing.

I had just received my new gun days earlier and was doing break-in shooting in my basement, had just over 100 shots through it and all was going as planned, dieseling was becoming less and less, accuracy at the short distance was one ragged hole with CP 14.3gr.
I was still getting accustomed to cocking this magnum rifle and used two hands to make certain I'd pull the cocking arm back the whole way every time. On the "fateful" cocking cycle, (thinking back after it detonated), I believe there was an "extra" click but I didn't investigate as the action closed as usual, then POW.... smoke poured from the breech and underneath the stock / action tube. Very surprising experience!
I immediately noticed a c-clip and half pin laying on the stool I used to support the rifle while shooting.  Turning the rifle over for closer inspection the other half of the cocking lug pin was rattling around and fell out. I found the shot pellet on the floor a few feet away....WITH rifling marks on it! it was pushed through the barrel with the little velocity that occurred as the broken pin apparently allowed the piston to recoil freely.

I phoned Umarex, spoke to a tech fellow and told him my experience, he emailed me a pre-paid shipping label and off went the action for repair. Got my action back in little over a week,,, no explanation from Umarex what had occurred other than what I already knew, so I phoned and spoke with the same tech and asked if the gun was dis-assembled and inspected for any other damage that may have occurred from the detonation? he replied that it was and no damage was found. ( I ? that now)
Well,,,,, as spring came and I got outside shooting, I was having accuracy issues with this gun,, minor, but still frustrating inconsistent accuracy.
I recently installed a PG2 kit and during dis-assembly I noticed my breech seal appeared odd looking, not smooth but rough, kind of disintegrated looking. I was still having the minor accuracy issue with the PG2 so I ordered some new breech seals.  Once I pulled the old breech seal I could clearly see the damage that possibly occurred when the gun detonated and has since been allowing inconsistent pressures likely causing my accuracy issues 'cause with the new seal this gun now shoots one inch groups, out to 35yds I've tested, with JSB 18 and 15gr ammo as long as I do my part.

Sorry for being long, but I like to be thorough in my explanations when similar experiences happen.
 
To Chris,, your 470 should be repaired without question, just hope they replace ALL the parts that may have been damaged and need replaced....not just the obvious broken ones. Good luck.

[kiraskillz]

Thanks jus tom.  The full story helps.

[palonej]

Hey Chris!!
Sorry to hear of this headache bro.
I have a 56, same action as yours with the sled system, and have experienced the same thing........along with several others!
I had major trigger issues, cocking lever issues and on and on and on.
Check out this thread. It went on for quite some time, but you'll get the gist pretty quickly.

http://www.gatewaytoairguns.org/GTA/index.php?topic=50444.msg478098#msg478098

I got the gun from AOA brand new and they were less than no help.
Spoke to Umarex and since the gun was tuned with a Vortek kit they refused to look at it.
I then sent an e mail to Diana via their web site.
I heard back from Glenn Seiter from Umarex. Not only did they pay shipping back and forth, they also rebuilt the entire rifle.......and sent an additional piston free of charge.
Try sending an e mail to Glenn at glenn@umarexusa.com
He's a great guy to deal with!
Good luck bro!!

[newlife3]

Hi Chris, fortunately you were not hurt when it failed!!! Without having the gun and it's broken parts in front of me, I can only make a guess at what has happened to your gun. First, because I haven't heard of any other Diana 470 failures like yours, I'd have to guess it's an isolated incident. Second, metal failures DO happen. Sometimes you'll see a air bubble in the metal or some other visible defect leading to the failure. I would take a close look at all the parts with as strong of a magnifying glass as I could get my hands on. Make sure there isn't any other parts that are hurting including the compression tube. Hopefully the holes where the pin fits wasn't hurt to the point of needing replacement. Then go ahead, replace what needs replacing and put it back together and try it out. I don't remember if you said the gun was still under warranty or not. Although in this case, I might be wanting to do the repair myself unless the comp tube is shot. Then maybe contact Diana in Germany, not Umarex and send pictures of the parts first before letting them out of your possession. They may want to replace the gun. Good luck with it and please let us know how you make out and maybe even what has caused all this. Have a great day - Lee

Pictures are important and maybe try photocopies on the scanner window of the pieces will give some extra detail..

[shootist]

Anytime anyone is looking for parts that won't be sold due to FFL regulations or just because they won't sell parts like Gamo, or hard parts to find like Diana pistons, should check out Chambers in the UK. They will sell any part for any gun they stock parts for, which is darn near anything for everything including powder burners. The shipping is quite fast considering the distance and the shipping costs are not bad at all. Lee

[Methuselah]

I had just received my new gun days earlier and was doing break-in shooting in my basement, had just over 100 shots through it and all was going as planned, dieseling was becoming less and less, accuracy at the short distance was one ragged hole with CP 14.3gr.

...

I phoned Umarex, spoke to a tech fellow and told him my experience, he emailed me a pre-paid shipping label and off went the action for repair. Got my action back in little over a week,,, no explanation from Umarex what had occurred ... he replied that it was and no damage was found. ( I ? that now)

I too have had issues with a Diana rifle and Umarex's only consistency in their responses so far have been their continued inconsistency.

They claim all are shipped dry and will NOT diesel, and as for qualifications, well - at least one of their Gun Technicians only pre-qualification was packing and unpacking them, really.  And it doesn't matter how many times in how many ways you prove what they say is wrong, they just double-down.

Sorry, got carried away, have to agree with other poster, write Diana factory in Germany, avoid Umarex.

[kiraskillz]

update, I got in contact with NIOA in Australia and they are happy to send me out the parts free of charge and told me there is a design weekness that makes them prone to damage with even slight dieseling.

 so I need to clean it out 100% and reassemble with non dieseling lubes.

I post up the results when I get the parts and lube.       

[DanD]

update, I got in contact with NIOA in Australia and they are happy to send me out the parts free of charge and told me there is a design weekness that makes them prone to damage with even slight dieseling.

 so I need to clean it out 100% and reassemble with non dieseling lubes.

I post up the results when I get the parts and lube.     

That's good customer support. I kept thinking you were in Washington state (WA), USA. Now I need to read your posts with an Australian accent, mate.