Tuning Bottle Swap on a Kral Puncher Pro 500, questions.

[CyberDyneSystems]

I haven't found any answers in a search and am hoping the Kral aficionados can help.

I intend to swap the aluminum bottle on my Pro 500 with a lighter CG with higher capacity. I'm a novice here, and so far I have only done this on an LCS, which is literally just twisted off, fully charged, and replaced.

I assumed that with the Pro 500 I would need to drain the bottle fully (likewise with a Kratos) but when I look at the Pro 500 bottle, it sure as heck looks like there is a valve between the bottle and the gun that's a dead ringer for the valve on a 500cc aluminum FX bottle like on a Crown or Dreamline.

Is it possible that the Kral is set up with a bottle valve?

Anyone able to walk me through step by step for swapping that bottle?

Any other easy tunes I should do while it's drained and apart?

Thanks in advance and Merry Christmas!

 

[Vetmx]

I know it’s Christmas Eve but I ate way too much food then way too much junk and now I can’t sleep. I will try to help you because I swapped bottles on my Kral Jumbo which is not really any different than your gun. Of course you know you have to drain it or your life will become complicated. My bottle was a mother of pearl to get off. The thread sealant or loc-tite they used required required some heat. I also used a pin wrench to hold the thing that you think or actually does look like a FX valve. The easiest way to drain the bottle is to shoot it down. Then take the drop block out of the gun. You will then see the back of the valve. I just pushed it down on a table and made sure there wasn’t any air left in the bottle. I personally don’t like beating on a valve by dry firing until empty. Unregulated guns hit the valve pretty hard. You don’t really need to go on some kind of modfest once you’re in there. The gun should be plenty powerful enough and you don’t want to wreck the nice bell curve that Kral figured out. The FX valve looking thing will unscrew from the drop block but you’ll still have to get it out of the bottle. I don’t have a lot of faith in the durability of these types of guns threads so I used my pin wrench to keep the thing from spinning while I used a strap wrench, and not a junker, to twist the bottle. I used a padded vice to hold the drop block during the whole process. Good luck. Hope yours is cooperative. I’ve heard some are.

 

[napairgunner]

Your Christmas wish has been granted! You need to buy this part https://canadashootingsupply.ca/product/kral-block-fx-adapter/ and then remove the bottle and adapter it comes with and add an FX CF bottle I used the 480 for my SuperJumbo makes a huge difference! KRAL bottle guns (except the Dazzle) DO NOT have valves in the bottle. YOU MUST empty the bottle first. You many need a vice and heat gun to remove the bottle I did. I turned the power all the way down and dry fired until empty from 100 bar. I recommend ALL Kral bottle gun owners make the same chance you'll be glad you did. Talon Tunes sells a replacement fill port that is a standard foster if you want to do that. PM me if you have any questions.

 

[Vetmx]

I didn’t use the piece from Canada shooting supply. I left the Kral piece in the drop block and a Daystate bottle threaded right on. Here is a pic of when I was building my gun and before I put a reg on it. Notice how my bottle is not quite as far forward as the gun pictured above. Not a real big deal but you don’t need to spend any money unless you absolutely can’t get that piece off your Kral bottle.

 

[napairgunner]

If you want the bottle to be removable so you can swap it then get the adapter which is what I wanted. If you just want to swap the bottle for a CF but keep it fixed then keep the adapter it came with.

 

[CyberDyneSystems]

Thank you both of you! And Merry X-Mas ! This is very helpful!

Being able to swap bottles without emptying was not when I was planing to do, but knowing about this option is quite tempting! I could then choose massive amounts of air, or a lighter smaller bottle depending. So thank you for the link and idea napairgunner. I might just go that way.



VetMX, I believe I understand when you say "take the drop box out of the gun" this is essentially removing the entire business out of the stock correct? (remember, first time Newb at this!) I recall I've seen this operation in Youtube videos for Akela and Kratos. (Funny how I can't find any such walk through for the Kral)

I think I can manage to figure out how to do that. Once I'm there I can imagine that working on the bottle will be much easier! OK, not sure when I will get to this, but now I have some idea of a plan.



thank you both for taking the time to help me out on Christmas!



EDIT, found a video of this on a Jumbo from the same sight selling that adapter. Wow, one allen screw?! Ok, I think I might be able to handle that!



https://www.youtube.com/watch?v=66uJFWUAnJ4

 

[Vetmx]

When you pull your action/breech block out of the stock, you will be able to remove the block that your bottle is attached to. It’s the thing I referred to a the drop block. This is what it looks like without the bottle on it. It’s just secured to the gun with a grub screw. You’ll see. Hope it goes smooth for you getting the bottle off.

 

[thammer]

I am not sure on your caliber of pro 500 but if you use a changeable bottle system the air flow from the bottle to the drop block will be limited and you will probably not be able to generate the power you want if it's a 25. There there is not a lot of plenum space built into the drop block. The adapter that goes between the actual block and the bottle is the same on all Kral and Benjamin bottle guns and can be easily sourced from Crosman if there's an issue getting it off. Any carbon fiber bottle will screw directly on to that threaded piece it is an M18x1.5 thread. 

 

[CyberDyneSystems]

Thank you Troy, that does give me pause. My Pro 500 is in .22 I'd be curious to know if you feel this mod would have any effect on that?

 

[CyberDyneSystems]

That went well

Thank you again for all your guidance on this project. Having now done this, I am pretty amazed at how straight forward it all is.

The old bottle came off with some serious persuading. I happened to have the correct wrench (26mm?) for the adapter, and this being a thick walled aluminum bottle I had no compunctions about using soft jaws and my bench vice. Not sure the heat helped, aluminum being so good at wicking heat way.

While I had it all apart, I also added a coat of oil to the Kral's very fine walnut stock.

New 700cc CF bottle,

Despite the fact that this 700cc bottle was specifically designed to specs from airgun enthusiasts to make it an easy swap for many rifles, (specifically M3) I did run into a problem. The width of the bottle at the throat where the threads are is 1/8" fatter than the stock aluminum bottles'. (1-5/16"+ vs. 1-3/16") This meant some slight rotary sanding using a rotary tool to open up the stock just a touch. Once done, it all dropped back into the newly shining stock with no issues;

Also noticeable in the photo above, part of the design specs for the new 70cc bottle, sadly, and extra long "neck". It's more than double the length of the aluminum bottle necks. You can see here how much neck is visible, despite the fact that this is screwed directly to the Kral's own bottle adapter. No FX valve funny business (yet?)

Here she is all done;

...

Tomorrow I will fill her up and test it all out. (knock wood, after opening with how easy this was!!!)

Thanks again for the help.

 

[Vetmx]

Now that’s a bottle. If you run out of air with that thing in the field, you’re shooting too much. It seems your aluminum bottle was like mine to get off. I don’t blame Kral for how they put it together. They don’t want some knucklehead untwisting it with air in it.

 

[CyberDyneSystems]

This worked out just fine! No leaks, and I haven't shot it enough to even find out how many shots! lol.



Also, I made a mistake on the numbers/BAR above, which mitigates my concerns about modding this to work with the FX bottle valves.

Every PCP I own except the LCS was rated for 200 BAR. I assumed this Pro 500 was the same. It is not, it is 250. The LCS is also rated for 250, not 300. I don;t know why i got 300 in my head. So if both my Pro500 and LCS are rated fro 250 and they are the ones with the FX bottle valves, then I cn indeed safely have a collection of bottles and swap them out. To be safe, I would not want to add the adapter to any of my 200 bar rifles.