$#%^&#@%^! Diana 350 N-Tec-piston won't latch

[JuryRigger]

I'm a happy man... 
Jesse

Yeah!

Good job!

For all intents and purposes, it is a new gun.

;-)

Keep us posted.






HM

Will do-going to get the scope back on her today (time permitting); and run another 40-50 shots through her...
And my chrony is in Chicago-they didn't throw it overboard this time! 
Supposed to get it Saturday; which would be about perfect if I can get another hundred or so shots downrange; she should be somewhat stable by then.
Jesse

[JuryRigger]

Got my speed meter today-and ran a quick 6-shot string (only six since I had it clamped to the barrel; and I do not intend to take the risk of shaking the chrony to pieces  )...
18-grain H&N Barracudas:
712 FPS
723 FPS
697 FPS ( )
718 FPS
730 FPS
723 FPS
Not sure what the 697 was about; I do only have about 100 shots through since the rebuild, and the gun was taken straight out of the air-conditioning into the heat; maybe it was just a fluke; but... ES of 33 FPS if I include that off low shot; and only 18 if I don't... That leaves me with an average FPE of 20.55 with the off shot; and 20.78 without it-just about what it should be   
Woo-Hoo! 
Now to rig a setup so I can get a longer string; and try some different weight pellets.... 
Jesse

[JuryRigger]

Been trying to upload this pic for awhile now-finally went through-you can see just how badly eroded the original seal was 

Looks like the entire surface had a 1/32" or so just evaporate, plus all the gouging!! 
Jesse

[Toxylon]

That's one of those things you have to see to believe! And I thought what a compromised factory seal looked like...

[JuryRigger]

That's one of those things you have to see to believe! And I thought what a compromised factory seal looked like...

Yeah-it's pretty bad 
And I was sitting here wondering all this time why the shot cycle seemed so violent-I've no idea how the poor thing lasted this long!!!
That broken trigger spring was the best thing that could have happened to me, otherwise I might have never took it apart and found that seal... 
Jesse

[JuryRigger]

Full chrony strings-note several items...

For starters, when I took the gun outside-it started sweating; 90° out with 70%+ humidity... So, it had some acclimating to do-guessing it was mostly equalized by the third string; as I only did one at a time before ducking back inside to cool off for awhile...

Also had a couple readings that made zero sense; but realized that the chrony was wobbling enough on the block it was setting on to get flipped up at one end upon firing, depending on whether or not the muzzle was pressing it one way or another; so I completely disregarded the two that were off; on the second string of JSB Jumbo 18.13gr (which was my last string)-otherwise no errors that I am aware of.

Here goes! (Suggest a cup of coffee-this will be a long post!  )

-------------------------------------------------------------------------------------------------------------------------

First string-gun cold, 18.13-gr JSB Jumbo Heavies:

736.5

730.5

737.4

742.7

740.9

734.8

728.8

741.8

732.2

736.5

Max 742.7 FPS

Min 728.8 FPS

ES 13.9 FPS

Avg. 736.2 FPS for an average of 21.82 FPE...

----------------------------------------------------------------------------------------------------------------------------

2nd string, 18.13-gr H&N Barracudas-gun still cold, but no longer sweating:

724.5

728.8

717.8

728.8

738.3

718.7

725.4

714.5

720.3

732.2

Max 738.3 FPS

Min 714.5 FPS

ES 23.8 FPS

Avg. 724.93 FPS for an average of 21.16 FPE...

-------------------------------------------------------------------------------------------------------------------------------

3rd string, gun mostly acclimated-21.14gr H&N Barracudas:

692.3

704.0

696.9

698.5

691.5

698.5

699.3

691.5

693.8

700.8

Max 704 FPS

Min 691.5 FPS

ES 12.5 FPS

Avg. 696.71 FPS for an average of 22.79 FPE... (Didn't expect that!)

-----------------------------------------------------------------------------------------------------------------------

4th string; 16-gr Predator Polymags-gun completely acclimated:

763.6

768.3

766.5

771.2

782.8

783.8

781.9

779.9

775

776

772.2 (11 shots, oops)

Max 783.8 FPS

Min 763.6 FPS

ES 20.2 FPS

Avg. 774.65 FPS for an average of 21.32 FPE (varmints beware )

--------------------------------------------------------------------------------------------------------------------------

5th string-now for a surprise ... 14.5-gr RWS Superdome:

843.3

853.7

841.1

843.3

836.5

833.1

833.1

838.8

830.9

836.5

Max 853.7 FPS

Min 830.9 FPS

ES 22.8 FPS

Avg. 839.43 FPS for an average of 22.69 FPE (So much for the blowby theory...  Was wearing hearing protection, as I was shooting inside the shed into a steel trap (with appropriate precautions against rebounds!), so have no idea if they still sound weird)

-----------------------------------------------------------------------------------------------------------------------------------------

Wanted verification of my baselines, so shot another 10 JSB Jumbo Heavies:

712.9

725.4

722

708 (ignored, think it was a bad reading caused by me)

718.7

717.8

720.3

703.2 (ignored again)

716.2

723.7

721.2

715.4

Max 725.4 FPS (vs. 742.7 the first go-round)

Min 712.9 FPS (vs. 728)

ES 12.5 (vs. 13.9)

Avg. 719.36 (vs. 736.2, or a 16.8 FPS drop) for an average of 20.84 FPE (vs. 21.82)

---------------------------------------------------------------------------------------------------------------------------

So, there we have it-expected some things, didn't others-especially how consistent and powerful the Superdomes were... Still do not understand that one, at all...

Looks like temp. does make a difference, though it was surprising to see it loose velocity as it warmed up...

Very, very happy with the overall energy and velocities, getting every bit as much as I had expected; going off the Hard Air Magazine review; of course I have no way of knowing if my chrono doesn't read 10 FPS higher than it should; or something like that, but still a good place to be.

Jesse

[HectorMedina]

Jesse;

I am glad you solved the issues and are now happy.
Yes, sometimes G'd's greatest gifts are unanswered prayers.
;-)

The results would be far more typical than you can imagine. The 350 NTec has a VERY quick shot cycle. And the first pressure spike is REALLY high. Pellets that can stand other pressure spikes simply "balloon" in the 350 NTec.

In this sense it is no surprise that the pellets with the thickest skirts are the best performers.

I am also sure that you can feel the difference and the shot cycle does not feel as "violent" with the Baracudas and  the Superdomes as it does with the others.

In  any case, Superdomes are not the most expensive pellets in the planet.

Congrats on a job well done!

Now test it at some distance and keep us posted!







HM

[JuryRigger]

Jesse;

I am glad you solved the issues and are now happy.
Yes, sometimes G'd's greatest gifts are unanswered prayers.
;-)

The results would be far more typical than you can imagine. The 350 NTec has a VERY quick shot cycle. And the first pressure spike is REALLY high. Pellets that can stand other pressure spikes simply "balloon" in the 350 NTec.

In this sense it is no surprise that the pellets with the thickest skirts are the best performers.

I am also sure that you can feel the difference and the shot cycle does not feel as "violent" with the Baracudas and  the Superdomes as it does with the others.

In  any case, Superdomes are not the most expensive pellets in the planet.

Congrats on a job well done!

Now test it at some distance and keep us posted!







HM

Thanks Hector; you are so correct about gifts-lemonade out of lemons, so to speak... 
That's the surprising part-the Superdomes used to feel/sound extremely violent; now they feel no different than any other pellet-I wonder; if that couldn't have been due to the worn seal-was there possibly enough leakage around it to create a situation where the piston bottomed out with the lighter pellet?... 
Who knows 
Getting groceries today; so if I have time I'll grab some Crosman Premiers, and add them to the lineup-then do a complete test of all the pellets again, hope the Superdomes do well-I have about 800 of them on the shelf!
Will get the test results posted as time allows 
Jesse