Evanix Tactical Sniper

[dogwood]

friction, it fits fairly tight.

[dogwood]

well second valve is toast 

seal material is so deformed that the metal valve "cap" is touching the valve body with minimal pressure, I verified it with a multimeter.

My friends 3D is still working well, I know Evanix is capable of making good guns, but mine seems to be a major lemon.

Starting to get a bit tired of this. 

[rkr]

well second valve is toast 

seal material is so deformed that the metal valve "cap" is touching the valve body with minimal pressure, I verified it with a multimeter.

My friends 3D is still working well, I know Evanix is capable of making good guns, but mine seems to be a major lemon.

Starting to get a bit tired of this. 

It kind of not worthy doesn't it - but you should think positive, at least you haven't encountered the bent sidelever yet. Evanix has rather decent design here, I just have to wonder why they have to flush it down the toilet with poor material choices and QC? Kind of makes me wonder if I should have waited for .35 Cricket instead.

Edit, as a first aid you can turn the seal around, it will work and will probably last until you can get a proper seal made for the valve. For the seal material PEEK works and PET-P is what I use currently. PEEK is a bit harder so it requires more precise surface to seal. You might also want to consider making a new proper valve without that o-ring in the stem.

I've had two Korean made guns now and nothing but poor experiences. I know I'll steer clear of anything Korean made from now on.

[QVTom]

Hey dogwood,

Now that you have a multimeter would you mind taking some dimensions and making a quick sketch of the valve?  I'm curious if the Tactical Sniper is running a larger poppet and the larger area is crushing the seat or they just have a material problem.  You can use my valve drawing for reference.

 http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=63424.0;attach=79311

Tom 

[dogwood]

rkr, how did you get the seal off? mine seemed to be glued in.

Tom, be happy too.

[dogwood]

rkr, how did you get the seal off? mine seemed to be glued in.

Never mind rkr, I figured it out, should have know it was threaded, they do seem to love threading everything.

[QVTom]

Just sprayed wine all over my screen.  Yes, they do love their threads.

[dogwood]

Just sprayed wine all over my screen.  Yes, they do love their threads.

LOL, sorry about that 

[dogwood]

Hey dogwood,

Now that you have a multimeter would you mind taking some dimensions and making a quick sketch of the valve?  I'm curious if the Tactical Sniper is running a larger poppet and the larger area is crushing the seat or they just have a material problem.  You can use my valve drawing for reference.

 http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=63424.0;attach=79311

Tom

Tom,
here's my valve drawing, did it in mm's but added some notes on with inch on that part that is different -  hope you can make sense of it.

Made a new valve seal today out of PEEK (got my lathe working well finely) hope to try it out tomorrow. 

[dogwood]

Finished pumping it up, popped the valve once - hissssss   

pumped it back up a bit more and loaded a mag - shot 7 shots, can't hear the hiss anymore   

set it down, going t eat dinner and then check the pressure- hopefully is stays the same   

[dogwood]

still had a really slow leak, put another mag thru it and that seems to have taken care of it, that PEEK is hard! 

Just when I think the barrel is going to be good it throws a couple off in the weeds, it is an big improvement over the other though.

it's shooting well enough I think to allow me to see if it is me or the barrel....

[dogwood]

well, I think we all know how it went 

first mag was hitting 3.5" high at 50 yards, adjusted 2" down and shot the second mag, first three shots went to the same place as the first mag? added another 2" down, 4th shot was 1" high and slightly left, 5th shot 1" low and 1" right, 6th shot 1.5" low and 1" right
7th 3/4" high and slight left 

third mag, no idea where the 1st shot went., second was 1.5" high and 2" right, 3rd was 2" below that, forth almost in the exact same hole as the second, fifth .5" left of 3rd. 6th .5" low and .5" right, 7th 1" low and. 5" right (-all JSBs)

think I'll stick to shooting round balls at 25 yards and save the JSBs until I can get a SeanMP-TJ barrel

[rkr]

well, I think we all know how it went 

first mag was hitting 3.5" high at 50 yards, adjusted 2" down and shot the second mag, first three shots went to the same place as the first mag? added another 2" down, 4th shot was 1" high and slightly left, 5th shot 1" low and 1" right, 6th shot 1.5" low and 1" right
7th 3/4" high and slight left 

third mag, no idea where the 1st shot went., second was 1.5" high and 2" right, 3rd was 2" below that, forth almost in the exact same hole as the second, fifth .5" left of 3rd. 6th .5" low and .5" right, 7th 1" low and. 5" right (-all JSBs)

think I'll stick to shooting round balls at 25 yards and save the JSBs until I can get a SeanMP-TJ barrel

If you get the TJ liner barrel let us know how it works. I'm considering going the same route myself.

BTW, are you sure it's not your scope that's the problem? Also, have you checked the barrel band and associated support system for binding?

Edit, I forgot to say one of the lads here tried 9mm LW airgun barrel in his Evanix and is now looking for something more accurate.

[dogwood]

well considering the things I've seen the scope might not be out of the realm of possibilities  - was just trying not to think about it....

Will probably explore the scope possibility for a bit, if it proves to be OK I might just get a carbon tube to put on the barrel before I make the  leap to a TJ.

[QVTom]

Hey dogwood,

Now that you have a multimeter would you mind taking some dimensions and making a quick sketch of the valve?  I'm curious if the Tactical Sniper is running a larger poppet and the larger area is crushing the seat or they just have a material problem.  You can use my valve drawing for reference.

 http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=63424.0;attach=79311

Tom

Tom,
here's my valve drawing, did it in mm's but added some notes on with inch on that part that is different -  hope you can make sense of it.

Made a new valve seal today out of PEEK (got my lathe working well finely) hope to try it out tomorrow. 

After comparing notes, it seems that the valve in the 9mm Sniper is the same as the 22 cal. RS with the exception of the poppet, throat and exhaust port diameters.  The area increase of the cap that holds the seal is 24%, this raises the closed force at 2900 psi from 385 to 503 lbs.  This is significant in terms of the compression on the seal and added energy to knock open the valve.  In the case of the Sniper's Delrin seal, assuming the sealing surface is .025" wide, this gives an area of .035^2" @ 503 lbs force = 14,371 psi stress in compression. Considering Dupont puts Delrin's compressive strength between 8,500 and 10,700 psi, it's no wonder these valves are failing.

Tom

Edit:

I also looked at the o-ring groove in the valve stem.  The reduced diameter is 2mm or 0.079", this is only and area of 0.005^2" .  Applying the 503 lbs required to knock open the valve at 2900 psi, the stem material would need to have a minimum yield of 100,600 psi  (no SF included), making both the material selection and heat treatment absolutely critical!  There is NO defending this design, even with tool or CM steel the fatigue of repeated hits will eventually cause a failure  .

[QVTom]

Edit, I forgot to say one of the lads here tried 9mm LW airgun barrel in his Evanix and is now looking for something more accurate.

if I understand correctly, the Lad was not impressed with the LW barrel either?  LW is a 1 in 16" just like Evanix?

Tom

[dogwood]

Put on a different scope, something I had laying around.
Here's almost $4 worth of JSBs shot from 50 yards ( the 4 shots near the center of the target where from the first string and at 20 to makes sure we were in the  ballpark)
didn't do anything between strings except pump and reload the same magazine




Going to put my other scope back on and stick with round ball at 20-25 yards, at least until I can afford to put a new barrel 

[Nomadic Pirate]

Now I don't even think it's a barrel problem, I just don't see 2 barrels in a row shoot worse than a Shotgun when there's so many accurate .357s out there, gotta be something else, why don't you try put that barrel on your friend Stormpup just to make sure ?

[QVTom]

Now I don't even think it's a barrel problem, I just don't see 2 barrels in a row shoot worse than a Shotgun when there's so many accurate .357s out there, gotta be something else, why don't you try put that barrel on your friend Stormpup just to make sure ?

Great suggestion.  Process of elimination...........

[dogwood]

Now I don't even think it's a barrel problem, I just don't see 2 barrels in a row shoot worse than a Shotgun when there's so many accurate .357s out there, gotta be something else, why don't you try put that barrel on your friend Stormpup just to make sure ?

Great suggestion.  Process of elimination...........

Yes an excellent suggestion thanks NP - since I have his gun I will do that tonight