Airgun Technologies Vulcan 3 HP 25 sudden speed loss

[Will74]

I would be interested to hear other shooter's experience about HP speeds i. 25cal.

Also I'm intrigued by the potential of adjusting the valve stopper. I believe mine was all the way in from the factory and it is now. And no, I absolutely had not touched it before speed loss so don't anyone go there. Seriously.

 

[Emu]

Why don't you call Tony at Talon Tunes and ask him for his advice?

He works every day with Airgun Technology rifles.

 

[Will74]

Why don't you call Tony at Talon Tunes and ask him for his advice?

He works every day with Airgun Technology rifles.

Thanks but so far it seems people are not interested. They can't be bothered to read these posts but they sure have opinions.
I have been in contact with two highly reputable people about this and I see it has been in vain.

I also wouldn't think any vendor would give their time to someone not having bought their stuff no matter how nice a person he was. Also my problem with this V3 probably isn't a problem if you ask anyone. Just shoot it, they would say, having never heard of this type of symptoms.

Thanks

 

[TMH]

I think that I have read most of this thread well, but please forgive me if I might have read over something quickly and am asking you to do something which you have already tried or has already been suggested.

When my V3/.30 cal also had a 'sudden speed loss' it turned out to be regulator creep. Have you shot your gun's bottle pressure down lower than where your reg pressure is set? On my gun the creep took the plenum pressure so high that the hammer couldn't effectively open the valve. UNTIL the bottle pressure dropped, and then things were 'back to normal',

I had a shot string where from full fill (for me 250-270 bar - I don't normally fill to 300) I would get continuously increasing velocity for the first 30 or so shots, then it would level off for just a bit before it would start dropping. And the velocity gain over those 30 shots would be on the order of 400 fps.

Replaced with HUMA reg and all is good.

Reg going bad would have nothing to do with your hammer work, but sometimes things happen coincidentally. And I see that you are shooting tethered sometimes, so the pressure in the gun's plenum never gets the chance to go down (if you have a creeping reg).

Easy enough to check...

Good luck.

 

[Will74]

I think that I have read most of this thread well, but please forgive me if I might have read over something quickly and am asking you to do something which you have already tried or has already been suggested.

When my V3/.30 cal also had a 'sudden speed loss' it turned out to be regulator creep. Have you shot your gun's bottle pressure down lower than where your reg pressure is set? On my gun the creep took the plenum pressure so high that the hammer couldn't effectively open the valve. UNTIL the bottle pressure dropped, and then things were 'back to normal',

I had a shot string where from full fill (for me 250-270 bar - I don't normally fill to 300) I would get continuously increasing velocity for the first 30 or so shots, then it would level off for just a bit before it would start dropping. And the velocity gain over those 30 shots would be on the order of 400 fps.

Replaced with HUMA reg and all is good.

Reg going bad would have nothing to do with your hammer work, but sometimes things happen coincidentally. And I see that you are shooting tethered sometimes, so the pressure in the gun's plenum never gets the chance to go down (if you have a creeping reg).

Easy enough to check...

Good luck.

Thanks.
I have pretty much covered that. Tethered and not.
I also was a bit surprised people telling me I absolutely need a reg tester. I have had relatively good results shooting through chrony until speed changes and that's why I appreciate Wika over factory. And sure, I would go for a tester if only it wasn't so immensely expensive to import. As far as I know only Talon Tunes is selling them.

I did stop to think if there was something going on with the reg when speed was on another level. Maybe it was creeping and has settled since.
Anyhow I set it around 210-215 for now.

I have lots and lots of air but still the air consumption scares me. It's just wild on that power level.

 

[Will74]

I remember it was shooting about 144J from factory. I just started increasing spring load and ended up getting 178J which equates to 130FPE if my memory serves me right. So it could have been creeping.