Tuning 25 Kral Puncher Mega Leak

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30harry

30harry

Member
Oct 30, 2018
262
6
Serbia-Beograd, Serbia and Montenegro
I get a small puff of air in my face each time it fires a pellet. The air is coming from the opening in the rear of the block directly beneath the end of the cocking lever. 

I've single loaded a pellet and put a small piece of tp over the pellet probe and it doesn't move when the airgun fires so I'm guessing it isn't the breech oring leaking.

I've watched a few videos on the puncher and on one Troy did, he said there are only three places it can leak and one of those was the transfer port. 

My question is, does this sound like that kind of leak and if so, how do you fix a transfer port leak on a puncher?

Any help is appreciated.

It is completely stock with no mods at all.

I'm getting about 650fps with jsb 33s and 770fps with jsb 25s on max setting if that helps.
 
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A puff of air during the firing cycle wouldn't be considered a leak. A leak is when air escapes while the rifle is not in use. What you're feeling is some of the air that would normally be traveling out of the valve transfer port, up the breech and then out the barrel. It's getting redirected somewhere. Most likely the valve stem if it's coming from the rear of the block. Air is coming out of the rear of the valve into the area where the hammer is located and then releases between the breech and stock. Fire the gun out of the stock and check here for the puff of air. 
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A puff of air during the firing cycle wouldn't be considered a leak. A leak is when air escapes while the rifle is not in use. What you're feeling is some of the air that would normally be traveling out of the valve transfer port, up the breech and then out the barrel. It's getting redirected somewhere. Most likely the valve stem if it's coming from the rear of the block. Air is coming out of the rear of the valve into the area where the hammer is located and then releases between the breech and stock. Fire the gun out of the stock and check here for the puff of air. 
1598240582_16407620455f4337469be0f9.69383261.jpg
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thank you hammer. When I put a piece of tp over that area and fire the puncher, it blows that paper across the room. So now I'm off to watch your Kral disassembly video again. Is this a "normal" problem with the Kral?? What is actually failing in it??

thanks again,

The other other Harry


 
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It's either just an oring failure or the actual stem is broken. Was common on older guns but not anything made recently. The new stems from pyramyd air should fix it with no future issues for quite a while.
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I've taken the barrel off and the orings look ok. I'm going to take the valve apart tomorrow and see what it looks like. When you say valve stem could be the problem, I'm assuming you mean air is leaking around the valve stem in the firing cycle back into the action? 

Also, weren't you selling an updated valve stem for the puncher at one time? Do you have any of those in stock?

Thanks again for your help.
 
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Mine has an enormous blast of air coming out of that noted horizontal opening where you see the hammer and spring hitting the valve when the power is cranked all the way down to minimum. At maximum power level there is minimal air coming out.
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After taking mine apart and after your post, I'm rethinking this problem. Kral adjusts "power" via the power wheel by restricting air flow from the valve up to the chamber. So it makes sense that if you turn it down to its lowest setting that would cause maximum restriction and increase the pressure in the valve area, forcing more air through the hammer area and creating the puff of air in the shooters face. Turning it to maximum power would reduce the restriction, reducing the pressure in the valve area and hence the puff would be a lot smaller.

So, is this a "defect" or a "quirk" of the Puncher?? How many other Kral shooters experience a small puff of air in the face when you pull the trigger?

I've ordered the valve stem from PA and will find out if it actually "fixes" the problem or just reduces it to a minimum.


 
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My two 22 Puncher Breaker Silent bullpups don't do it. Maybe because their actions are set more deep inside their stocks IDK?Just my rifle does it and it's a 177. Common sense would say to lessen the hammer spring tension for less of a hammer strike for less air blown. Or swap to an Ace Hawdware weaker spring. I have done neither yet and just let the gun grumble to me because it's been too quiet since my divorce.


 
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My two 22 Puncher Breaker Silent bullpups don't do it. Maybe because their actions are set more deep inside their stocks IDK?Just my rifle does it and it's a 177. Common sense would say to lessen the hammer spring tension for less of a hammer strike for less air blown. Or swap to an Ace Hawdware weaker spring. I have done neither yet and just let the gun grumble to me because it's been too quiet since my divorce.

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The defective part on mine is Kral P/N AT22 and that's probably what is bad on yours. On mine, there wasn't enough of the oring left in the groove to even begin to measure it. If you order the needle valve from PA, it should include the oring. I ordered but have not received mine yet so not sure until it is in my hand.

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I put an oring inside the valve stem hole when I do mine. There's going to be blow by if not. You do lose power without a sealed valve stem.
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Ok wasn't sure, but just use them anyway, even though I've seen several that do not have them, or a groove on the stem for them.

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I guess if the tolerances were close enough you wouldn't need an oring. But the needle has to be free enough to move too. The looser the tolerances, the more air that will blow through the valve if there is no oring. I'm still waiting on the needle from PA. 
 
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Well, I was going to post an update about how I replaced the bad oring and now the puff of air coming from the back of my 25 Mega is gone but sadly, it's back. I put around 100 pellets through it after putting it back together and then all of a sudden PUFF.

Along with the puff, I discovered that my Kral won't shoot through a moderator. I tried three different ones I have and none of them would group near the POI without a mod on it.

And they all group to a different POI. I compare that to my Avenger 22 and it groups all three moderators to the same POI or very close.

After a lot of pellets down range I am ready to call it quits on this airgun. I retired my first PCP, an Umarex Gauntlet because of similar problems. i can only spend so much time on trying to fix a problem or problems before I begin to understand it isn't an FX or Daystate that I am trying to fix and maybe it will never be what I want it to be.

I'm now going to order an Avenger .25. I like the way they are put together and I am really liking my 22 and the options for tuning. There isn't another airgun like that out there yet. 

Goodbye Kral. You were like 40 more miles of bad road.
 
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30harry said:
I get a small puff of air in my face each time it fires a pellet. The air is coming from the opening in the rear of the block directly beneath the end of the cocking lever.

I've single loaded a pellet and put a small piece of tp over the pellet probe and it doesn't move when the airgun fires so I'm guessing it isn't the breech oring leaking.

I've watched a few videos on the puncher and on one Troy did, he said there are only three places it can leak and one of those was the transfer port.

My question is, does this sound like that kind of leak and if so, how do you fix a transfer port leak on a puncher?

Any help is appreciated.

It is completely stock with no mods at all.

I'm getting about 650fps with jsb 33s and 770fps with jsb 25s on max setting if that helps.
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Hi there.

I am having the exact same issue where my Kral Puncher Bigmax .25cal is only giving me 670ft/second max with 33grain Jsb’s which is really not good.

I see on your thread you talk about a disassembly video, where will I be able to find it so I can try and sort my issue out.

My issues sound exactly the same as yours, did you manage to sort it at the end ? And any advice ?


Regards
 
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