Two (2) of them. Same caliber and same month and year of Manufacture. BUT they are 2 different animals. The one shoots quieter and smoother and better. The other is twangy and rough.Both have about the same number of pellets thru them (maybe 150).
I did a test today with the Chrony and got 2 sets of different results. All pellets were the BSA 16 gr Wolverines (JSB Exacts maybe). One shot 600.5, 594.4, 594.4, 595.3 and 588.4. That was the "Good One". "Bad One" was 423.9, 416.3, 432.1, 433.3, and 433.2.
Since they are just 1 year old, my plan is to send the "Bad One" to Umarex and let them see what is wrong with it. Does anyone else have any numbers that might help me out? Or maybe some ideas as to what I should check.
First place I'd look is at the Breech Seal on the bad one.
Visually inspect it first then either cup your hand over the Breech joint, place a tissue over the breech joint, or put some baby powder over the joint and fire it. Leaks will usually show right away...
The company IS good about honoring their Warranty!
data provided and work done by John in PA all I did was send him the 34. he also did some custom work with the piston and installed buttons to the piston, wood stock was done by Tim and all machine parts (top hat, rear guide, spacers, etc.) by Rayburn11
these are all members of the Dianawerks forum
warren
and remember "it's 30% the gun and 70% the shooter"
(Piston and/or breech), broken spring, bad compression tube - could all lead to low velocity. "Tissue test" will tell you about the breech seal; broken springs will often (but sometimes not) have skronky cocking; piston seal can be diagnosed by disassembling gun and doing a visual, combined (only when gun is dissassembled!) with manually pushing the piston forward with your finger sealing the port - bad seal/comp tubes will bleed down, good ones won't.
After you've eliminated the breech seal(easy), my best guess is a bad piston seal; for whatever reason, a lot of these are trashed right from the factory (you can skip that step).
I ran Warrens Numbers on the "Good Gun" as far as a lighter pellet and his original numbers match closely, 630fps on a 14.3gr VS my 16.2gr at 595fps. The Foot-Pounds calculates out to 12.58 in both examples. Warrens Numbers were 635 AVG. But he sure had a good increase in numbers when he had the work done.
For now, I think I will send in the "Bad Gun" under warranty and see what I get back. Hopefully it will be smoother and will match the original numbers. I can then tune it up from there, if I need to. Since I have 2 of these, it might be fun to tear one apart and make it "Hot".
I did as Hector suggested by checking that the gun was UNLOADED and blew into its barrel. Both were about the same. NOT airtight, but not a large leak. I probably will have Umarex send me some breach seals (O-Rings) and spacers. Then I can fix these as necessary. Does anyone have the seal size available? I can also try to get some locally. And what would be a good hardness for the seal? Vitron or Buna?
Thanks for the help and if you have any other ideas, please feel free to add them...
Nice numbers with that power tune! 16.5fpe! Almost a 4fpe increase with those spacers.
How does the gun shoot? How is the shot cycle and accuracy? Is this with the spring set or not? Did you go with a JM piston seal or OEM?
Once again Hector comes thru with INVALUBLE info!! Yea the tissue test,, the powder test,, Let me tell you,, Hectors "blow test" is pure genious!! Why in the heck did I not think of that?? Bill, based on your posts about your "slow" 34,, the fact that you said it was "scruncy" cocking,, that & based on other info you have provided,(& it seems to have passed Hectors test) really makes me think you may have a broken mainspring on your hands. Im shure it could be something else I am overlooking, but, shure sounds logical to me. If I were you I would NOT SHOOT that gun anymore,obviously something is NOT right & it could cause further damage if you continue to shoot it. (But of course you know this). If it is still under warranty I guess you should send it to Umarex for repairs. I have dealt with them many times, for the most part I have had decent service with good turn around time from them. Just remember,, fixing the "Symptoms" does not always deal with the true underlying problems a particular air gun may have, especially if "underlying" issues may exist. Good luck Bill, I hope you get both of your 34,s up to par,, Keep us posted,, Tim.
The 34 in .22 cal that Timmy took a few shots with a couple weeks ago, has a GRT and JM seal, so now it has a much more consistant spring than was in it from the factory. The factory spring was kinked and the seal was sliced up pretty well too, but it is doing much better now.
Shoots the 16grain Exacts at 706, but the shot cycle is alot better with 12grain hobbies at 850, or 14.2 grain Trophy at 780 and soda can accurate at 80m with both of the lighter pellets {although it is a different aimpoint at that distance}
Hello Freinds,
I am kumar from India and am about to buy a all black Diana model 31 in .22 calibre with a synthetic stock. Can any of you tell me the highand low lights of this model? I have 2 Model 34's and have nothing to complain. One of them is made in 1967.Pls help.
Thanks
Kumar
