Air Gun Home :: View topic - Regulator Pressure question--

packrat · Senior Member

OK...here's my situation...I just finished converting an AS2250 to HPA, using 13 c.i. Ninja bottle..I have put FOUR red shims in it and I still do not have enough pressure for what I want.
Gun has 16" ,.177 caliber barrel, I plan to use 10.5 pellets at ~20FPE...this means I need 890-920fps..the max I can get with shims is 9.5 FPE.......I'm afraid to use any more shims in regulator and have decided it's easier AND SAFER to just use a jdsairman regulator on the ninja bottle..My question is this..what size regulator do I need ? I can tell you this, for reference..I have another 2250 (Bmodel) with 18" .22 caliber, 13 c.i. jdsairman bottle with 1600psi regulator..I can shoot 14.3 pellets at 850 fps (with PA all the way out)....so, the AS2250 has 2 inch shorter barrel, and almost 4gr. (3.8) lighter pellet. Obviously, 1600psi would put me over my target of 20fpe..so, that leaves 1250 and 1400 as my 2 choices..naturally I want to use as little air as necessary for the sake of shot count. Do ya think 1250 would handle it, or should I go with the 1400psi just to be sure...there's only $5.00 difference in the price so, that's not a concern..using as little air as possible is what I'm thinking of....so, who's got experience with this?? I know if it were in .22 caliber it would be simple, that's what everyone has(including me!!) I just wanted soething different. thanks for all your help Smile

rsterne · Moderator

Does your Ninja reg have a coil spring or disc springs (belleville washers)?

If it has the coil spring it's a low pressure reg (450-850 psi) but that means nothing as the reg itself is the same as the one with the disc springs....

Here is my thread on shimming Ninja regs:

http://airgunhome.com/agforum/viewtopic.php?t=4564

For reference, I have a modded 22XX for FT use in .177.... It has a 1500 psi reg. and can shoot up to 22 FPE.... I only have to back the adjuster down a couple of turns to stay under the 20 FPE limit for FT use....

I find .177 is a lot less efficient than .22 cal in HPA.... at least on the guns I have tried.... the same holds true on CO2.... I'm guessing you will need 1400 psi rather than 1250 to shoot 10.3 gr. pellets at ~850-900 fps in .177 cal....

Bob

packrat · Senior Member

Thanks Bob..yeah, I know the .22 is the more efficient, but I've already got a couple of those and just wanted to have something that will use cheap pellets and get lots o' shots per fill...to kill toy soldiers and those evil urban soda cans..Plus, I didn't have an AS2250 and figured it was time I got one..I had re-read your post about your .177..I was aware that the reg. I bought was the low pressure version,( which has the coil spring, NOT belleville discs) but figured I could tinker with it and bring the output up to what I wanted. Hell, it was only $70.00 for bottle and regulator so I figured what the heck.....I did NOT know that the actual reg. part itself was the same...I suspect I'll just get a 1400psi reg.from jdsairman and go from there .Then I'll see if I can find parts to convert my low pressure to a high pressure....gives me something to do Cool

thanks for timely answer !
BTW,,the threads on ninja reg. and jds reg. are the same aren't they/ Both use the B&A AS-to-PB adapter, right?? Iask because the B&A adapter I have woerks finw with the ninja bottle , but woudl NOT screw onto the jds regulator..I iwas going to try the 1600psi bottle I already have on the AS2250 gun, but like I said, jds regulator would NOT screw into the adapter...did I just get a "freak" one??

rsterne · Moderator

YUP.... answered in other thread....

Bob

packrat · Senior Member

OOPS--pardon me, I forgot I had already posted that question Embarassed

I thought they were all the same..and I KNEW for sure that if there was 1 bad one in a batch of say 632 million, I would get it..It's just always been that way.. Think I'll just order the 1400psi reg. from jds and use it with ninja bottle...

packrat · Senior Member

If the regulator body of the low press. and the hi press. are the same....what parts would I need to just "gut" my LP version and build it up as a HP unit? I have a reg. re-build kit, like the one on scopes/ammo site...but as far as belleville washers and such...is it gonna mean shopping @ McMaster's Carr or Graingers to get the parts? Anyone know of a break-down picture of the ninja 1500 reg. ?? I'd like to see what parts are involved.... I ask because I just remembered that I have 12 belleville spring discs from a 1250 Dominator regulator...IF these are of a usable ID and OD, they just might be the ticket Smile

I'm guessing the spring is just removed and replaced by appropriate number of bellevile washers in a single stack configuration, using Bob's 800psi stack up as a starting point.....sounds right to me...what say ye of higher knowledge??? Am I on the right track..it's important cause someone told me some time back that HPA can be harmful or even fatal, so I ask Laughing

rsterne · Moderator

They use belleville washers instead of the coil spring.... but the body is the same.... If you pick up the bellevilles from McMaster-Carr you can get the 5/16" ID x 5/8" OD x 0.032" thick.... get a dozen and put them in :

)) ( ) ( ) ( ) ( ) ((

This will allow you to go from about 1200 psi up to about 2400 psi with just shims.... 0.050" maximum shims.... Look here:

http://airgunhome.com/agforum/viewtopic.php?t=4564

Bob

packrat · Senior Member

That, I believe is my answer. Smile

when you typed 0.050" maximum shims, you mean that's the max. height of each washer, right??

rsterne · Moderator

By 0.050" I meant that IF you add shims to the belleville washer stack (on one end).... don't go more than a total of 0.050" of shims.... You will probably only need about 0.010" to get to 1400 psi anyway....

Bob

packrat · Senior Member

GEEEZ Bob, I wonder just how dense I can be..you plainly said shims..I was thinking washers, not about the shims...forgive me, you must think I'm some sort of scatter-brain idjit......the signs ARE pointing that way..THANKS..it has finally soaked into my brain..maybe I should go back to drinking Question

rsterne · Moderator

Pour me one.... Mr. Green

Bob

packrat · Senior Member

CRAPOLA !!!!! Followed directions exactly,,stacked bellevilles and test, then added a red shim and tested te added another red shim and tested...The highest fps witj the 10.5 Crosmans is 700 fps....no matter how many belleville and red shims I use..I even added another bellevile (total of 13) and 2 red shims....700fps is max...I can tell by the sound that it just isn't gettin' air, no where near the same sound as my other 2250 which has same LDC and both have max-flow valves, same TP, etc..only diff. is one has jds bottle, othe has the ninja... Anyone got any idea of what is wrong?? Why won't the ninja regulator flow more air???note: with the 13 bellevile and 2 red shim set-up, it blew the 1.8 burst disc !! HELP !!
Could it be that I need to remove the pin from the reg. and from the adapter??? could that be restricting my air flow??
One more thing , the stock spring with no load measures 0.533"...the 12 belleville washers stack-up, with no load measures 0.0530"...NOT alot of difference there??

rsterne · Moderator

Sounds like you need more hammer spring.... If you blew the burst disc, pressure sure ain't the problem.... I'm getting over 900 fps with 10.3 gr. JSBs in .177 with only 1500 psi and a 24" barrel.... and a Disco hammer spring.... The low noise is also an indicator of not enough valve opening.... A very short pulse of high pressure makes very little noise.... I'm only using a stock Disco valve (much less volume than a max-flow)....

Regulators don't really "flow" air during the shot.... they only top up the space betweend the regulator and valve and inside the valve itself between (immediately after) the shot....

The belleville washer stack may measure about the same.... in fact it should.... The difference is in the spring "rate".... ie how much force it takes to compress the spring.... The disc springs are "stiffer" than the coil spring....

Bob

packrat · Senior Member

And wouldn't ya know I have several kinds of springs, but no disco..I had a 2289 spring(which is same as 2250B) in it, ...guess I hafta to wait 'til Monday, and order some more from Crosman.....shucks !! Crying or Very sad

:cry:Perhaps with only the 16" barrel, 890-920 fps is expecting too much......certainly gonna take more "pizz-zazz" to get fps that high

packrat · Senior Member

Well as usual Bob, YOU ARE THE MAN..I found one spring that was unmarked,,no idea what it's for...just for the helluva it, I gave it a pull or two, intentionally stretching it, but EVER SO slightly...tried it in the gun...fps (w/10.5 pellets) went from 640 to ~720..I have no intention to use it permanently, but it verified what you suggested was the issue Cool

Friend of mine from TAG forum sending me a disco spring, along with some others....so, that should do it...