Kral Puncher Breaker - The King is Dead.... After 2600 rounds

[Flatpicker]

Well, my Kral PB broke the valve stem a couple nights ago.  Had just shot it over the chrono the night before and it was shooting CPDs at 920-968-920 over four mags- a little less power than stock as I had tinkered with HS settings. Took it out to mop some starlings and when I pulled down on the first one and pulled the trigger all I got was a "click". I thought "huh, that's weird " so I took the mag out and tried again.  Same thing. Dang!  Back to the house 1/2 mile away and opened her up to find the valve stem rattling around once the hammer was pulled back.  I have a hard time thinking that this would fail after less than 3000 cycles, but have heard of valve stems breaking before; I'd just never experienced it. I feel like the wise old owl on the Tootsie Pop commercial- "how many licks does it take to break my Krals valve stem?"  Lol. Have contacted  Air Venturi and am awaiting their response. Real bummer is I've had the PB for 37 days.... So much for returning it.  I DO know there has been an issue with the Evanix guns breaking stems a few years back, but was hoping the metallurgy would be better with the Kral. I'm hoping maybe someone can offer a suggestion of how to de-gas the gun so I can ship it (currently sitting at 200 BAR) or just fix it myself. Don't get me wrong, I love the rifle, but am disappointed about my current dilemma.  Does anyone have a source for valve stems? Thanks to everybody in advance!

[Motorhead]

First off ... BUMMER 

Second ... sadly when folks KNOCK OFF designs nearly tit for tat they also get that designs short comings if present.  The EVANIX valve stem breakage at the o-ring groove is well known among those working with them.

As to an alternate ... Will Piatt at Saddle Mountain gunsmithing would be top of my search list being EVANIX guns are some of his top guns across his bench. 

[Rob M]

i think the fastest way to get it back up and operational might be contacting Travis ..He knows the guns pretty well now , and would also know the easiest way to degas it. Sorry to hear about the issue., it does sound very familiar though, I think this happened to someone last month also..

[Flatpicker]

i think the fastest way to get it back up and operational might be contacting Travis ..He knows the guns pretty well now , and would also know the easiest way to degas it. Sorry to hear about the issue., it does sound very familiar though, I think this happened to someone last month also..

Yep.  My thoughts exactly. I dropped Travis an email earlier in the day but I know he is a busy guy these days.  Will Piatt would be a great contact too- Thanks Motorhead for that suggestion.  I think Will may have a more robust solution for the valve IF it is indeed identical to the Evanix.

[Motorhead]

Travis is in route to Placerville for this weekends Air Gun show. Told me he would be heading out @ 1:00 PST and has a nearly 5 hour drive to arrive here 6:00 ish.
I may be having dinner with him this eve, Sat night for sure & will run it by him 

[LeE]

I am speaking from personal experience with my Kral. Since you have the bullpup, there is a way you can degas the gun. It involves removing the air cylinder from the action which is held in place with 2 set screws on the bottom, forward of the trigger group. In order to remove the air cylinder, you will need to do the fallowing in this order: 1) Remove the stock. 2) Loosen the cap screw on the Rail/Trigger body assembly so that it will slide freely from the air cylinder. 3) Loosen the set screws underneath the action, forward of the trigger group. 4) Separate the air cylinder from the action. 5) Finally, on the valve body you will see a brass colored set screw that holds a flat disk underneath (this is where a pressure gauge would go if it was the rifle version) which holds the air in. If you carefully loosen that set screw a tad until you hear a slow hiss, you can safely depressurize the air cylinder.  If you decide to do this, please do so at your own discretion.

For a permanent fix, I would machine a new valve stem from S7 tool steel and heat treat it. That stem would outlive the gun.

[Flatpicker]

I am speaking from personal experience with my Kral. Since you have the bullpup, there is a way you can degas the gun. It involves removing the air cylinder from the action which is held in place with 2 set screws on the bottom, forward of the trigger group. In order to remove the air cylinder, you will need to do the fallowing in this order: 1) Remove the stock. 2) Loosen the cap screw on the Rail/Trigger body assembly so that it will slide freely from the air cylinder. 3) Loosen the set screws underneath the action, forward of the trigger group. 4) Separate the air cylinder from the action. 5) Finally, on the valve body you will see a brass colored set screw that holds a flat disk underneath (this is where a pressure gauge would go if it was the rifle version) which holds the air in. If you carefully loosen that set screw a tad until you hear a slow hiss, you can safely depressurize the air cylinder.  If you decide to do this, please do so at your own discretion.

For a permanent fix, I would machine a new valve stem from S7 tool steel and heat treat it. That stem would outlive the gun.

Many thanks!  Will approach with caution in the morning!

[Hunt4dinner]

One way I found by accident to degas a gun is to use a hand pump or tank to fill both the cylinder and tank to an equal pressure. Once they are if using a tank shut the valve then barely open the pressure relief valve just so the air slowly leaks out. If using a hand pump once it's up to pressure just barely open the relief valve so the air slowly comes out. It takes a little while but I degassed my prod one morning trying to not wake the wife and kid with the big burst of air from bleeding the pressure from my hand pump.

[anti-squirrel]

Kinda depressing to hear about the Kral's valve-stem failure.  On the other hand, I am willing to bet this type of information gets back to Kral.

That the aftermarket now has a starting point on them coupled with a low purchase price means they will end up filling a niche like the MRod/Disco and Hatsan AT-44. So who's going to start selling aftermarket valve/stems?

[Flatpicker]

Update:  talked with Will Piatt and am sending him the valve and broken stem. Also talked with PA and they informed me they had no spare parts yet, so I requested an Evanix Blizzard valve.  Received it today and it is slightly smaller than the PB's stem. Put it in anyway for grins and because of the smaller stem diameter (and lack of O-ring) there is considerable air loss and velocities are a whooping 235 fps at max...it would appear Kral did try to improve on the Evanix design by making a larger stem, they just didn't use an alloy which holds up to the repeated hammer strikes. Hopefully Will can turn one down out of S7 and I'll be good to go again. I don't have the milling skills, but if anyone is interested in a precise drawing of the Kral valve stem I'd be happy to email it.

[LeE]

Update:  talked with Will Piatt and am sending him the valve and broken stem. Also talked with PA and they informed me they had no spare parts yet, so I requested an Evanix Blizzard valve.  Received it today and it is slightly smaller than the PB's stem. Put it in anyway for grins and because of the smaller stem diameter (and lack of O-ring) there is considerable air loss and velocities are a whooping 235 fps at max...it would appear Kral did try to improve on the Evanix design by making a larger stem, they just didn't use an alloy which holds up to the repeated hammer strikes. Hopefully Will can turn one down out of S7 and I'll be good to go again. I don't have the milling skills, but if anyone is interested in a precise drawing of the Kral valve stem I'd be happy to email it.

I am interested in the drawling. Sending you a PM now. Thanks for the offer!

Will you be doing a fallow up if Will is able to machine a new one? It's a real shame there is no product support with the Krals as of yet. I hope they aren't like the Korean gun makers and impossible to get spares from.

[SADave]

Hopefully you can get it resolved soon. Ive been keeping my eye on the Kral Puncher Pro for a while. Tough to find a gun with a walnut stock at that price. I know on my Theoben Rapid you're not supposed to dry fire it without it being charged for fear of breaking the valve stem.

[Gertrude]

I have a buddy who is new to airgunning and bought a Kral PB .25 as his first airgun.
He has had this gun for just about a month now, and has about 1500 rounds through it.
 Although I am an experienced airgunner with several other brands and models,... I have ZERO personal knowledge or experience with Kral guns.

This past Saturday, while we were enjoying a great day of shooting, his gun did exactly the same thing as described by Flatpicker in the original post of this thread. I have seen the few threads where  others have also had these poppet stems break.

Last night my buddy called me to tell me he tried to fire the gun after he got home, and his description of what happened next was...
"It sounded like the gun EXPLODED, followed by an immediate dump of all air remaining pressure,... and now it will not pump up and hold any air at all".

I told him to test it again by cocking the gun first, and then try to put some air in it.
 He did this, and said it will not hold any air, and he can hear it exiting out the barrel as fast as it is going into the gun.
 
This indicates to me that the gun is probably the next victim of yet another broken valve poppet/stem.
 I will be seeing him again this coming Saturday, and will probably be bringing the gun home with me for disassembly to verify.

I have read where Will Piatt has made, (and may be willing to make more) replacement stems for these guns.
 Does anyone know what the cost of a replacement stem from Will would be ?

 I have also read about cocking handles and sears breaking on these guns.
 Does he also make upgraded replacements for these parts as well ?

I will try to contact Mr. Piatt tomorrow. I am also aware that Travis has some knowledge on these guns and their problems, so I will probably try to call him too.

 Any advise or suggestions will be greatly appreciated, as I am just trying to help out a friend and new comer to airgunning.

[rkr]

Update:  talked with Will Piatt and am sending him the valve and broken stem. Also talked with PA and they informed me they had no spare parts yet, so I requested an Evanix Blizzard valve.  Received it today and it is slightly smaller than the PB's stem. Put it in anyway for grins and because of the smaller stem diameter (and lack of O-ring) there is considerable air loss and velocities are a whooping 235 fps at max...it would appear Kral did try to improve on the Evanix design by making a larger stem, they just didn't use an alloy which holds up to the repeated hammer strikes. Hopefully Will can turn one down out of S7 and I'll be good to go again. I don't have the milling skills, but if anyone is interested in a precise drawing of the Kral valve stem I'd be happy to email it.

So Evanix no longer has the o-ring groove in their valve stems? The Blizzard should have 4mm stem while my .45 Sniper has a 4.5mm stem, that might be a direct fit for Kral.

[Flatpicker]

  Thanks rkr!  I've been shooting the PB alot lately and still enjoy it, but wish I could gain back those 30-40 ft/s that I had with the stock valve stem.  The Sniper stem might be the answer.

[TroyHammer]

I just placed an order for some S7 drill rod. I'm going to try and get some replacement stems made up. They will be a direct replacement for the stock poppet. Unscrew the old and replace with the new one. I'll update the progress next week.

[kkarmical]

Troy,
Awesome, I really like the way you & Matt and a couple of others are openly trying to help keep these guns working.  Keep up the good work!

[Geronimo]

Looks like we might have to start a new sub group. Broken kral owners club. Sad because I truly enjoy mine. It is a shooter. Well it was, now it is wall art. Hoping Troy and others can get some replacements made and ready. I'm anxious to get it working. All of the new parts from various places will be an improvement to a nice little rifle with potential. The bling doesn't hurt my feelings either. Good luck and I'll let everyone know if I get a replacement.

[Gertrude]

So Evanix no longer has the o-ring groove in their valve stems? The Blizzard should have 4mm stem while my .45 Sniper has a 4.5mm stem, that might be a direct fit for Kral.

  Thanks rkr!  I've been shooting the PB alot lately and still enjoy it, but wish I could gain back those 30-40 ft/s that I had with the stock valve stem.  The Sniper stem might be the answer.

So has anyone here verified whether the stem for the Kral is the same dia., length, threads, as the stem for the Sniper ?
Has anyone ordered a Sniper stem yet to find out ?

[kkarmical]

So Evanix no longer has the o-ring groove in their valve stems? The Blizzard should have 4mm stem while my .45 Sniper has a 4.5mm stem, that might be a direct fit for Kral.

  Thanks rkr!  I've been shooting the PB alot lately and still enjoy it, but wish I could gain back those 30-40 ft/s that I had with the stock valve stem.  The Sniper stem might be the answer.

So has anyone here verified whether the stem for the Kral is the same dia., length, threads, as the stem for the Sniper ?
Has anyone ordered a Sniper stem yet to find out ?

I tried going the Blizzard route for a replacement lever that might fit, in the end after it was all said and done it didn't work out so I just ate the $$, it was tip money so it didn't hurt so bad, on this I'll wait on Troy to make up replacements, save myself the headache.