Has anyone done any modifications to their Benjamin Kratos? I was particularly wondering if I could swap the factory bottle for a 580cc carbon fiber bottle. This would mean lighter weight and a greater shot count. Would this swap entail removing some wood from the fore-stock area where the new cf bottle would be installed? This was the case when Steve of AEAC installed a cf bottle to a Kral Puncher Jumbo. I suppose a little work with a dremel tool, as Steve used, would not be too difficult. A good shot count is important to me. For hunting it might not be so important, but sharing a shooting session of plinking and/or target work with others would mean less delays in refilling the on-board tank. This rifle, with its 5-year warranty, seems like a good choice for both the indicated applications. Because of the hunting laws in my state, I would be ordering the rifle in .22 caliber. Thank you in advance for your input and I wish you a very Happy New Year!
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Modifications to the Benjamin Kratos
- Thread starter pcpwannabe
- Start date
Couple posts on that same thing in last week or so...yes its posible with a little sanding on the stock for the slightly larger neck of the carbon bottle!
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I put a .5L CF tank on my 25 Kratos, it saved 9.6 ounces and gives a few more shots. I also watched the trigger modification that TheAirgunDetective put out. It made a big difference and is simple to do.
Make sure you sand your stock channel.
Great air rifle.
Regards,
Roachcreek
Make sure you sand your stock channel.
Great air rifle.
Regards,
Roachcreek
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That's kinda nice RC! Bet you have a lot less trouble with it than the last Diana bullpup. GRRR!!!!
Mike
Mike
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Hey Roach,
that bottle looks like a 4500psi one. Did you also put on a reg? If not how is the gun responding to the added pressure unregulated? How is the 25? I have the 22.
that bottle looks like a 4500psi one. Did you also put on a reg? If not how is the gun responding to the added pressure unregulated? How is the 25? I have the 22.
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The gun isn't rated at 4500 psi. Changing the bottle doesn't mean you can use higher pressure. The valve system is the same used in the Pro500 so 250bar should be fine but please never attempt a higher fill than that.
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I originally posted some incorrect measurements on the bottle in this post and this is the correction, the correct size is 2.4 inch/60 mm diameter bottle is what I used, I sanded the bottle area on the stock, the bottle just clears the shroud.
I drilled out the air stripper holes, added wool in the shroud, a 4 inch piece wrapped around the barrel, then replaced the shroud spring with two of the Kratos baffles and 1 3/4 felt wrapped curlers. It is noticeably quieter, but still has a noticeable ping. I have the Donnyfl shroud adapter coming.
I did the first part of the AG Detective video, adjusting the screw until the hammer drops,then back off until it cocks, I did not polish, the result was a 1.5 lb poll.
About the ping, I need rid of it! Although my Kratos is only shot at 10 yards on the low setting of 450-500 FPS with Kings, and very consistent with velocity it does not need a regulator for shot to shot variation. However, I have a Altaros regulator in the 22 FPE setting coming for the ping, but it will also allow me, and I am guessing on this, to get nearly 200 shots per fill, and get rid of the ping.
My only gripe is that the pressure gauge is 600-800 psi off, as the oem pressure gauge will be used as the regulated pressure, I need to replace it. I just called Crosman, it took a while before the nice Crosman lady found it, but it is on its’ way now.
I am loving this 25 Kratos.
Regards,
Roachcreek.
I drilled out the air stripper holes, added wool in the shroud, a 4 inch piece wrapped around the barrel, then replaced the shroud spring with two of the Kratos baffles and 1 3/4 felt wrapped curlers. It is noticeably quieter, but still has a noticeable ping. I have the Donnyfl shroud adapter coming.
I did the first part of the AG Detective video, adjusting the screw until the hammer drops,then back off until it cocks, I did not polish, the result was a 1.5 lb poll.
About the ping, I need rid of it! Although my Kratos is only shot at 10 yards on the low setting of 450-500 FPS with Kings, and very consistent with velocity it does not need a regulator for shot to shot variation. However, I have a Altaros regulator in the 22 FPE setting coming for the ping, but it will also allow me, and I am guessing on this, to get nearly 200 shots per fill, and get rid of the ping.
My only gripe is that the pressure gauge is 600-800 psi off, as the oem pressure gauge will be used as the regulated pressure, I need to replace it. I just called Crosman, it took a while before the nice Crosman lady found it, but it is on its’ way now.
I am loving this 25 Kratos.
Regards,
Roachcreek.
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About how much for the bottle and where to purchase, sorry for the ignorance I am new to pcp and my kratos is the first one fore. Thanks in advance
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I never tried shooting it at 4500 psi, I have a head injury, but I am not insane. The rifle does handle 3625 psi safely though and I checked with the Ktal guru before trying it at 3625.
Remember while reading this, I am shooting at 11 yards.
The Kratos. is till evolving.
I swapped the 4500 psi bottle for the TalonTunes 3625 psi bottle that I had on my Texan LSS 257, as it is lighter and slightly smaller diameter and gives just a bit more clearance, but I also put a Altaros low powered regulator on it. On the highest settling on the power wheel, I get 550 FPS with Kings and the Kratos became much quieter with no ping and much less air hitting the power adjuster at 1100 psi regulator settling. I got north of 250 very accurate shots.
Then I bought a MP Mold in 48 grains, removed the regulator and put it on the original tank, it still gets around 200 shots, but with the shortage of pellets, counting the shots just to see how many I get is too expensive.
I am casting and experimenting with the MP slugs now, at 650 fps I get .5 inches at my 11 yard range and around 30 shots before accuracy falls off, at this point I do not know if it is due to impulse pressure falling, lower velocity as the pressure drops off or fouling, or all three. The slugs shoot terrible in the normal point first position, I turned them around to shoot base first and they shoot tiny groups. So a week into the experiment, I have found lower weight equals lower diameter and poor accuracy, which I have been telling you guys for years now, but at 48 to 48.2 grains, sized to .252 and shot backwards, I get a very accurate wadcutter with a nonconventual boat tail, go figure. A single shot adapter has to be used with these long slugs.
On full power, Kings shoot very well, but I had a cliff bell curve, meaning a very constant drop from 885-900 FPS, but due to the large bottle that drop us very gradual. I removed the stock and adjusted the hammer spring out to 1/4 turn and do get a few shots that actually climb from 870- 875 FPS or so then decend in FPS, but not many and that 1/4 turn is as far as it goes. I tried tuning it up for the slugs, it does turn a few turns, but no noticeable increase in velocity. So for now it is either a 47 FPE rifle running flat out with either Kings or the 48 grain slugs, or a very sedate, accurate low powered shooter with the regulator.
As it comes from Benjamin, the rifle does not need a regulator for full power use or turned down for plinking. It shoots like a regulated gun with a balanced valve due to the large air storage and effortless sidelever function. I added the regult9r as I shoot indoors and wanted a very quiet rifle, and the regulator removes the annoying bottle ping. Also remember when you turn that power wheel down, it is a non repeatable air steangle adjuster. That restriction is getting hit with the full air pressure regardless of the lower velocity and being as the power wheel has no setting detents, getting it to return to a low powered sweet spot requires use of a chronograph.
With a regulator for low powered shooting it is as mentioned above, a very quiet rifle and very accurate, but not something that has to be done.
A note about switching bottles, I have done this a dozen times or more, other than the initial sanding the stock channel and using a lot of air, you have to depressurize, I have never experienced a leak doing this.
Hope this helps, be careful and safe,
Roachcreek
post script, I got the 3625 psi cf TalonTunes bottle from TalonTunes, but have no idea what it costs in this post Covid world.
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I ported mine to .187 for the valve and barrel, .156 for the receiver and .176 for the power adjuster, then I cut two coils off the vrs. After that I polished the barrel and choke. The barrel and choke measured .254/.251 respectively.
My velocity gained just under 100 fps with Kings to 945-966-945 FPS, for 50 shots and with the 48 grain MP Molds slug, sized .251 for the choke, I hit 710 FPS.
Really pleased with this well built, well designed Kratos.
Roachcreek
My velocity gained just under 100 fps with Kings to 945-966-945 FPS, for 50 shots and with the 48 grain MP Molds slug, sized .251 for the choke, I hit 710 FPS.
Really pleased with this well built, well designed Kratos.
Roachcreek
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I'm about to do the bottle swap on my Kratos for a 500cc CF. Thanks for the great info in this thread!
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Im new to the kratos and air guns in general. Can anyone help me with just getting the tank off and getting it loose before I head to the airport incase they want to inspect the airtank off the rifle...thanks
Terry
Terry
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Just drain the air from the tank by cracking/unscrewing the fill nipple until it hisses, then unscrew the bottle.
Hope this helps.
Roachcreek
Hope this helps.
Roachcreek
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Since this got bumped,
I ended up doing a bottle swap to 500cc carbon fiber. Makes an already pretty lightweight rifle even lighter.
I also worked on my Kral Pro 500 but took that even furhter. I added an FX Bottle adapter that allows it to hot swap bottles betwen it and my LCS. I have two 700cc, one 580, and one 480 in CF, and three 500cc aluminum bottles all rated for 250 BAR.
I ended up doing a bottle swap to 500cc carbon fiber. Makes an already pretty lightweight rifle even lighter.
I also worked on my Kral Pro 500 but took that even furhter. I added an FX Bottle adapter that allows it to hot swap bottles betwen it and my LCS. I have two 700cc, one 580, and one 480 in CF, and three 500cc aluminum bottles all rated for 250 BAR.
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Sorry to hijack but just looking for some pointers on this kratos bottle removal. I released all the pressure off the bottle, Put a rubber strap wrench on it and it would budge. I pulled the stock off( one bolt ,,wow) and put the strap wrench back on ...no go. Should i put it in a vice and try to remove. Wonder if I have to remove the brass bolt in the pic, or something else...thank you
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I had the "block" in a vice, (between wood blocks as padding) and used a strap wrench. I can't recall if it was the kratos or the Kral Pro 500, but on one of them I had to apply a little heat with a torch.
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The first time I removed my bottle it was tight. After that I just hand tightened mine when reinstalling..
Bottles are often difficult to remove the first time. Removing that screw is not your path to removing the bottle, however it is how you replace your burst disc if you ever need to replace it.
If you have a padded vice I would put the receiver carefully in the vice and put a wrench on the wrench flats on what the schematics call the bottle cap. It resembles a collar to me, but Benjamin lists it as a bottle cap.
Good luck, you will eventually get it removed.
BTW, I ported my 25 Kratos to .20, it now shoots 25 Kings at 1050 fps on a full fill.
Good luck,
Roachcreek
Bottles are often difficult to remove the first time. Removing that screw is not your path to removing the bottle, however it is how you replace your burst disc if you ever need to replace it.
If you have a padded vice I would put the receiver carefully in the vice and put a wrench on the wrench flats on what the schematics call the bottle cap. It resembles a collar to me, but Benjamin lists it as a bottle cap.
Good luck, you will eventually get it removed.
BTW, I ported my 25 Kratos to .20, it now shoots 25 Kings at 1050 fps on a full fill.
Good luck,
Roachcreek
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