2400kt, Bottled, Regulated

[aPpYe]

The stock end cap has a hole in it where the spring sits. I take a spent .22 casing and put it inside the spring. This is what the 10-32 bolt will push on.

You just saved me some money!

Stock hammer will be fine to 1400psi. You will probably have to get a stronger spring. If you search the 22XX HPA posts you should see the springs that different guys are using.

As far as the Disco Valve - I would get that right from Crosman. I think they are about $13. You can also get the springs there. I think the 2100 or 13XX springs are what you want. Get all your part #'s in order and then call them. It will be $4 shipping for everything from there.

Except for the block and the regged bottle ... I guess I am going to have to go with at least two different vendors.  I haven't looked hard yet, but I think"@rchery airguns" sells odds and ends parts like this as well...  I haven't shopped around for a block yet, but they are the only ones I know offhand that has them.

I wonder if Crosman will let me simply add a few items to my existing CCS order...

[rsterne]

Get a "power adjuster" (RVA) from Crosman for the Challenger, it even comes with an appropriate hammer spring.... Heck, you might even get them to install it?.... 

Bob

[aPpYe]

Hmm.  I can get a tap and die set from Harbor Freight for about fifteen bucks.  If I do the homemade version with the .22lr casing I can have the satisfaction of having cobbled it together myself...  AND it gives me an excuse to go buy some tools!

On the other hand, I do like the knurled head on the bolt in the crosman version.  I would assume this means it is easy enough to adjust by hand, without the need for tools, however I do see a "pin" in the Challenger EVP, which I assume is used to hold the adjustment in place... Likely that would need a screwdriver to loosen.   How would I hold the adjustment in place with the homemade version anyway?  Does the spring tension hold it in place well enough on its own?

It occurs to me that I might want a cross-slide vise to drill all of these holes... This is starting to turn into a slippery slope!  I suppose I could manage to clamp things on my drill press...

The power adjuster assembly for sure comes with the spring?  I see that they are listed as separate parts, and the assembly on crosman's EVP does not show the spring in the complete assembly.

Also, for the PROD screws (1700-010), I wonder if I need to order three of that part number, or if they come in a set ...

Last, is there much difference between the 1377 spring and the Challenger spring?  I guess I would want the one that supports the largest range of adjustment ...

EDIT:  Aaaand another question!  I keep coming up with these.    I am not seeing any of the older style QB79 blocks available, only the new style with FOUR o-rings.  This is all well and good, but I was wanting to add another set of screws to the tube and use only the front o-ring on the old style, as rsterne (Bob) has done. The placement of the existing screw holes has me worried, as the grooves cut into the "meat" of the block.  I keep imagining myself leaning the gun against a tree to take a leak, it falls over and now I have a torpedo that crushes my legs while I am mid stream and whistling a tune.

[rsterne]

I prefer an RVA with a large screw (3/8") so that you can remove the hammer spring to swap it without having to disassemble the back of the gun.... Unfortnately, even the Challenger RVA doesn't allow that.... Mine came with a spring.... Unless the 1700-001 part number says something like (screw set - 3), then I would order 3 of them.... The Challenger spring is very similar to a Disco spring, so stiffer than a 13XX spring....

I have never used one of the new 4-oring QB blocks.... Given that choice, and the screws still close to the end of the tube.... I would either use it as is (with better screws) and a 1.8K burst disc.... or instead of modifying it use the one from JDS Airman.... more money, but the hole is further from the end of the tube, which is a much better idea....

Bob

[aPpYe]

Huh, actually the part numbers for the challenger and discovery springs are identical...  So I guess the only question I can think of today is ... What stronger screws?  Can I use PROD screws there as well? I was looking at the JDS adapter today and it seems like all they did was purchase the old style block and put holes in it!  Do you know if the JDS ones already come with the stronger screws?

[rsterne]

PRod screws will fit the Disco valve.... The heads are smaller, but if you are drilling the tube that doesn't matter.... I think the JDS is drilled and tapped for 8-32 screws, not the Metric ones in the QB.... You would have to ask about the quality he uses, if he even knows or will tell you.... There are only two, so you still should use a 1.8K burst disc for the build....

Bob

[aPpYe]

I guess I will make a call tomorrow.  I will also try calling “archery guns” to see if they may still have the older style block. The new style makes me kinda nervous.

So I am finally researching regulators and tanks.  It seems there are quite a few that are available in the $50-$60 range.  In fact, I see standalone 4500psi regulators for under $20...  Most, if not all that I have come across on ebay, etc are equipped with 1.8k output side burst discs, and either 4.5k, 5k or 7.5k tank side.  These generally come with 800-850 psi output.   I see that a lot of people here are going with the ninja brand, but if I can still stay safe, and save some money, I don't mind going generic.  Any thoughts on that?  Are the burst disc and output pressure adjustment shims generally universal?  Are they all adjustable for higher output pressures?

Also, I see that the 3000psi bottles typically come with a 4.5k burst disk, not 3k…  I would think this will avoid accidentally bursting the tank side disk because I filled to 3001psi …  I will be using a hand pump, and my understanding is that it is pretty grueling to pump past 3000psi anyway.  My thinking is that I will rarely even fill to that level anyway, preferring to pump until it starts getting hard, and living with a lower shot count.  I don't know honestly, as I have never pumped up a PCP before.  In fact, I put a 7 rounds through a disco about 5 months ago, and that is the sum total of my hands on PCP experience!

[rsterne]

Generic Regulators will not necessarily adjust in the same manner as will a Ninja regulator.... Some will have Belleville washers, and others coil springs.... The Ninja 850 psi regs come with a coil spring, you can't adjust them upwards, certainly not over 1000 psi.... To do that you need the SHP regulator, which uses Bellevilles, or you can swap out the coil spring an install Bellevilles.... I have heard reports of some of the imported regulators not holding consistent pressure, which to me means they are not worth the money.... Some don't have two burst discs, and I would NEVER use one without that feature.... The one QB79 I know of that blew up failed because of a cheap reg. with no 1.8K downstream burst disc that bypassed 2600 psi into the gun.... The screws on the tank block sheared off (and the holes nearly pulled out of the end of the tube), sending the tank block / regulator / tank assembly flying across the shop.... Change of shorts required, although nobody was hurt....

The input side burst discs are rated at the Hydrotest pressure, which is 5/3rds the Working pressure of the tank.... A 1.8K CO2 tank uses a 3K burst disc, a 3K HPA tank uses a 5K burst disc, and a 4.5K HPA tank uses a 7.5K burst disc.... If you fill too close to the rating of the disc it will pop, they are only accurate within about 10% (and usually on the low side, for safety).... Repeatedly cycling at near the burst pressure of the disc will fatigue the metal, and eventually it will fail.... The 1.8K discs are intended for the output side of the regulator, and you can usually fill to 1500 psi repeatedly without them failing, but if you use 1600 psi they usually fail after several cycles (and sometime immediately).... Sometimes they will fail on 1500 psi after many cycles, and again, sometimes very quickly.... I have never had one fail with the reg. set at 1400 psi, but have heard of it....

Bob

[aPpYe]

So when these discs do fail, is it just a loud bang and rushing air, or will the pressure still send things flying?  Also, are the ninja SHP regs the only ones with a disc on both sides that can be adjusted to 1400psi?  What about others, say tippmann or gorilla, etc?

[rsterne]

It goes bang, with a VERY loud hissing.... quite startling.... If the gun is sitting near the edge of a bench and the venting is pushing it towards the edge, it may have enough force to knock it off the edge.... Same thing it it's leaning against a bench or table, it may fall over....

Most regulators have two burst discs now, but that wasn't always the case.... I have no experience with Tippman or Gorilla, or any of the Chinese regs. from eBay.... I have only used Ninja, JDS, and RAP4, and they all use Bellevilles except the low-pressure Ninjas....

Bob

[aPpYe]

So I see three different price points here then.  In your experience, do they all hold consistent pressure?  Without that, the whole point of a regulated gun is moot.  At the risk of sounding like a pest, have you found any of these three to be more consistent or "better" than the others?  I have never been one to jump to the assumption that the most expensive one must be the best ...

Also, assuming I go for the ninja or rap4 (the JDS can just be ordered in the pressure desired), would I also need to purchase additional washers and shims (are these the same thing?) from somewhere to get the 1400psi I am going for?  Thanks again...

[rsterne]

Number 1 choice for me would be the Ninja, on a 13CI tank,, purchased from Tim @ Mac1.... He will set the regulator to the pressure you want, and he replaces the factory O-rings with MilSpec which allow the reg. to hold pressure over a narrower range, with longer life.... I think he will set up one with a 1.8K burst disc for 1400 psi, you would have to ask him.... He certainly will for 1200....

Bob

[aPpYe]

Hmm.  Therein lies a problem.  Mac1 is out of stock on the the 13ci combo!  The 22ci seems a bit long and/or heavy to me.  If I were to get the MAC1 regulator, is it a simple matter to screw it into another tank, say the 13ci or 17ci tanks from rap4?  They sell the tanks without the regs.

[rsterne]

Call Tim.... likely he either has some on the way, or will shortly.... All the common paintball tanks use the same threads.... 5/8"-18NF....

Bob

[aPpYe]

Okay, so once this check clears, tomorrow should be the big day to order the rest of this gun! 

Anyway, I was having trouble deciding what size bottle to get, so I took the time to create a mockup, using vendor measurements I see for the various bottles and regulators.  Assuming that Crosman's Custom Shop is reasonably accurate in showing the different barrel lengths, and my math is right, my 24" barreled 2400kt should be just about exactly 42 inches long, and have a nearly SEVENTEEN inch trigger pull!!!  That's longer than any of my other guns.   I may have to shorten that stock, extend the dovetail back or look for other solutions...

Anyway, having made this mockup, I discovered that I don't think I am gonna like a forward mounted tank with a tank block.  That tank is way out there! I am thinking I will go ahead and reverse it.  I guess it would all start with the end cap.  Are the existing end cap orings away from the threads?  Would a Disco end cap with its existing nipple work?  Initially, I was thinking to go with a flexible hose and a quick release, as this would allow me to easily remove the tank without having to empty it...    As you said, so long as I use fittings that are rated for these pressures, I should be okay, right?

For this idea, I figured I could epoxy some metal to the bottom of the tank, bend it at one end, drill a hole and use the screw that mounts the  trigger group into the tube.  Of course I am basing this design on the fact that there is a screw in that spot on my 1377, and assuming that the 2400kt has the same trigger frame.  Is this the same screw that goes into the bottom of the valve?  I could also just send a post into the trigger guard itself, but would rather avoid that...

For mounting the bottle, I was thinking of making something similar to what HappyHunter made here:
http://www.gatewaytoairguns.org/GTA/index.php?topic=81046.msg774493#msg774493

... of course there is always bending hose clamps ...

One of the things that makes me shy away from solid connections (pipes, elbows, etc) is that the tank would have to be supported by a pipe sticking out of the cap, and I don't want to put undue stress on it. Is this a valid concern?  I guess rigidly mounting the bottle would take care of that, but then why not go with hoses at that point?



... Any thoughts or recommendations?

[rrdstarr]

I prefer an RVA with a large screw (3/8") so that you can remove the hammer spring to swap it without having to disassemble the back of the gun.... Unfortnately, even the Challenger RVA doesn't allow that.... Mine came with a spring.... Unless the 1700-001 part number says something like (screw set - 3), then I would order 3 of them.... The Challenger spring is very similar to a Disco spring, so stiffer than a 13XX spring....

I have never used one of the new 4-oring QB blocks.... Given that choice, and the screws still close to the end of the tube.... I would either use it as is (with better screws) and a 1.8K burst disc.... or instead of modifying it use the one from JDS Airman.... more money, but the hole is further from the end of the tube, which is a much better idea....

Bob

All my RVA's are 3/8" with fine threads, just like Bob stated.

[aPpYe]

So you just drill and tap a hole in the existing cap yourself then?  What about a set screw?  Or do you lock it with a nut or something on the end?  I would worry about a set screw, because that might mar the threads.  I think I can manage to do something like this reasonably well enough.  Of course, I can always just buy the Challenger RVA and be done with it!!!  Also, I could always drill that one out later on if I am feeling adventurous…

Also, I was thinking about my "quick disconnect" idea ...  I see from some other threads that the Discovery fill adapter (Crosman # 1761-101) should thread into the tube as is.  I like the idea, but I am wondering if a threaded connection (versus using the fill nipple) might be less prone to leaking...  Once the gun is tuned, I doubt I would be needing to depressurize all that often...  Also, what is this gonna do to my tube volume? 

I see that Mac1 has a steel braided hose that should work well enough for me, I figure 6" would be enough, but maybe I might want to go with the 9" for extra volume?:
http://www.mac1airgunshop.com/braided-stainless-3k-9-p/psibrss.htm

Now I just need to figure out what adapters to put on each side... 

For mounting the tank, if the epoxy and metal idea isn't gonna work, I can always clamp to the tube in two places...

[rsterne]

I don't think you will be able to bend a hose 180* in that tight a space....

Bob

[aPpYe]

Hmm.  Hadn't thought of that!  What about using a couple of elbows then?  What thread am I looking for? 5/8 x 18 unf if I remember right?  I could then use a hose between the second elbow and the fill nipple.  Would you recommend going with a rigid part there as well?

[rsterne]

I'm personally not crazy about cobbling together fittings to do a job that should be done with a single machined part, but that's just me.... The only thread that is 5/8"-18NF is where the regulator screws into the tank.... The output of the regulator is 1/2"-14 NPS, sealed with an O-ring.... The female threads on the QD fitting are 1/8" NPT.... If you use a standard paintball tank valve (that fits on the 1/2"-14 NPS threads), they usually have a side port, which you could arrange facing upwards, that is 1/8" NPT female threads.... One more elbow and you could have the flow facing back towards the QD, and that could all be done with 1/8" NPT threads, PROVIDING you use high pressure fittings.... Do NOT use brass plumbing or gas-line fittings for this job, only ones rated for at least 3000 psi.... You might need a short hex nipple (double male) in the valve, and then a street "L" (female to male) to get the right height....

Bob