QB79 Ninja - The $200 PCP

[Ribbonstone]

To add to the confusion, you could HPA a Crosman.  Will need to swap valves for a bulk fill valve and add secure that valve a little more solidly, but the same tank block works.

Made this one for my Nephew.

[Geoff]

one could also go HIPAC for 85$ on their crosman.  if not for having to buy a pump, i would have tried one in mine

[toine]

To add to the confusion, you could HPA a Crosman.  Will need to swap valves for a bulk fill valve and add secure that valve a little more solidly, but the same tank block works.

Made this one for my Nephew.

Hey Ribbonstone, seeing as Flying Dragon is no longer selling QBs, could you post some more details on this build? Thanks.

[Ribbonstone]

Nothing complicated.

2250 tube
bulk fill valve (believe it's an old "boss")
Qb79 tank block
tube cut/drilled for tank block mounting
13ci HPA tank (that one is an 850psi output tank)
24" barrel cut to 20" (just long enough to allow the TKO to mount without touching the tank)

Used a brass RAP4 on/off between tank and block

They make paintball stock adaptors now. When i made that one, lathed the paintball stock's metal fitting to the same size as a Crosman end cap, drilled and tapped it, and recessed  it for the rear of the hammer spring.  Way too much work, get the adaptor.

[rsterne]

If you're after lots of power, don't cut the tube too short, in fact better to start with a 2260 tube, or you will end up in the same boat as with a QB79 where you are fighting against too small a plenum volume between the regulator and valve.... For low-medium powered guns, the shortness may be worth it, however....

Bob

[rewinder]

Well I'd like to report on my efforts to duplicate your fine work Bob. I started with an older, used QB79, I just bought, that came with a new SHP ninja tank, rap4 on/off/gauge valve and  arrrowman repeater breech kit all installed. It looks to be fitted with a MM tuned valve. and an AJ muzzle beautification.

The SHP is stock, I guess, it reads about 1200 on the rap4 gauge, a better gauge would probably be in order.

As received it shot 760fps, the previous owner said it would do 760 for about 60 rounds, I found that to be right about correct, then i ripped it apart.

1st I ported the barrel to #20 drill, It already had a pointed bolt from the repeater kit. When I assembled it I used a crosman 22xx rubber TP ring.It had a plastic water line seal before.

I removed the piercing pin in the valve and shortened the aluminum tube some, made a valve spring standoff and milled wider slots on the OD. Didn't do the maxi-valve thing.

I put 2 more tank block screws ahead of the original ones, and used 8-32 cap screws.

Lastly I made up a RVA, after converting to cock on open ( drilled a new hole in the hammer, about .3" rear of the original one. put a .75 l x 3/4" OD spacer behind the cocking pin  for the RVA to adjust the preload.

Reassembled and tried it out

I started from weak preload and went up by turning the RVA in, till i got max fps, then backed it out 1/2 turn or so, max was around 835fps, i lowered it to 820. happy with that! Didn't see how long a string i could get at the setting yet, will do it soon.

Then I twisted on a full 9oz co2 tank and from the same RVA setting, walked it out till the fps started to drop. The tank and gun were 58-60* at most, since I was in my cold basement. The max on co2 was 637 average at the previous hpa setting, I lowered it by about 15 fps thinking I was on the "knee" then.  It only took a turn and a half ( 10-32 screw)  So now I can use both fuels and be somewhat  efficient on either, by slight adjustment.

next I'll mount the scope and try different pellets. I had a ball doing this, and thanks to you Bob, it was easy!!!!

I'd post a pic,but everyone knows that a qb79 looks like. The AJ muzzle thingi is 1 1/2 X 10".

[rsterne]

Glad it worked out for you.... congrats !!!

Bob

[rewinder]

Thanks Bob,I'm just a copy cat, you're the innovator!

I forgot to mention, I found the hammer spring preloaded with 2 common washers , on the cocking block pin, and I didn't put them back when i reassembled it---- should I put them back? Or wait and see , but how would I know if they are needed?

thnanks

[rsterne]

Shoot a "power curve" using the preload adjuster you made.... Set it up on the knee of the curve.... Don't use the shims unless you can't get enough preload....

Bob

[rewinder]

Ok that's what I planned to do when i get some free time and and warmer weather for plotting on co2 also.
If i could get my wife out of the house when I'm not working, I could just open up a window haha.

[rewinder]

I snuck some time at work to fool a bit with the 79, Iswapped out apoppet I had that seemed to have a harder seat, it was white (delrin maybe?) and had a tapered brass body too, i opened the brass part of the valve some on the lathe, and lubed up the hammer, & reassembled.

Since daylight savings is here, it was light enough to use the crony, the hpa velocity didn't change much ( max  848, adjusted back to 825), but the co2 did. it maxed out at 665 vs 637 the last time (still around 60 degrees) . I'm adjusting the RVA by screwing it in to find max, then dropping it back  about 15fps to get on the knee.  This time I ran out of increase adjustment, cause I couldn't cock it  (this is on co2 now, I had no problem on air finding the knee). Maybe I'm coil locking the hammer spring on co2?? I did put 2 common washers behind the spring this time.

here's a picture (I hope it gets attached!) with the huge lcd and repeater breech,

Next up is to shovel off the back deck and set up the bench,sight in the scope.

The co2 will have to wait for warmer weather,, but now i can practice in the cold with air

Any one have any suggestions to enhance this project?? I really don't mind tearing it down, using the 2240 TP rubber seal ring makes life easy, I can use it over and over it seems

[rsterne]

You say you can't find the maximum velocity on CO2.... that is VERY strange, as you should need a lot less hammer spring tension than on air, and the colder it is, the less you will require to find the max. as the pressure is lower.... It is possible you can't find the knee because you can't screw it OUT far enough?.... that would be more likely....

Bob

[rewinder]

Ya know I think you ar e right, I was in a hurry, supper was ready and wife was impatient. I just wrote down a couple of numbers and went up stairs.
 At my age ya get excited, distracted, then ya mix things up.

I need an hour or so with no interruptions and a pad of paper! Any how, I'm happy with it and won't open it up again till I do more testing.
EDIT:
sitting here thinking about is now, i adjusted with air first, swapped tanks reloaded mag and wife called down to me for supper--- distracted , i shota few on co2, all the while screwing IN the RVA lol wrote down the co2 #'s and went up stairs--- i just now remembered i forgot to shut off the chrony. It ain't pretty gettin old

2nd edit-this one is correct:

Looked at my 79 and the ninja is on it, so i tested on co2 FIRST, found the knee at fps listed above

THEN I put the ninja on and in screwing the adjuster in, I got to  around 838, wife called as i got to point of not being able to cock, backed off a bit, went upstairs. I posted thinking co2 was the last run on chrony, when it really was air.

That makes sense now haha. So maybe 838 is the top of the curve, I think it is sitting here now.

going to watch Bill O and forget my embarrassment 




thanks Bob

[rewinder]

I ran a fully charged ninja today to get a shot count.

With tinned  22 CHP's
Full ninja SHP, reg is stock, not shimmed. But the rap4 valve gauge reads 1200, and creeps to 1300 after a few min.

 adjusted RVA down to 820, got about 62 shots -- was hoping for 80!
All shots deviated only 12 fps max.
before the reg was bottomed out, I put 2 15.9 exact's thru for fun, and got 780fps.

I was hoping for more shots, the velocity is OK my me.

So I'm not near as efficient as yours Bob, maybe I need to increase tube volume by chopping the valve's aluminum off like you did.
How about boring out the drop block forward some (from tube side) to add volume?
Maybe make a solid delrin valve poppet on the old stem--(should a new delrin valve's sealing face be 90 degrees to the stem, or angled concave or convex?)

Any suggestions appreciated!

It's fun fooling with this thing.



BTW, on co2 it maxed out at 662fps, but the co2 tank and QB were about 55deg

[sr1sws]

Question... Flying Tiger is not selling QBs at this time.  Found them at ^&$@_=s.  Archer says you need their paintball tank adapter to keep the tank away from the barrel.  Have the QB79s changed dimensions to require the adapter or is the vendor just working to sell a $32 chunk of metal?

Thanks!
Steve

[nervoustrigger]

Flying Tiger is not selling QBs at this time.

Crouching Tiger...Flying Dragon? 

Found them at ^&$@_=s.  @=S+S%^$# says you need their paintball tank adapter to keep the tank away from the barrel.  Have the QB79s changed dimensions to require the adapter or is the vendor just working to sell a $32 chunk of metal?

If using a 13ci Ninja brand tank, you do not need anything special to install it on a QB79.  The standard issue tank block works fine and usually leaves 1/8" of clearance between the tank and barrel. 

Some other brands of 13ci paintball tanks are a little larger diameter and may not fit.

[sr1sws]

Flying Tiger is not selling QBs at this time.

Crouching Tiger...Flying Dragon? 

Found them at ^&$@_=s.  @=S+S%^$# says you need their paintball tank adapter to keep the tank away from the barrel.  Have the QB79s changed dimensions to require the adapter or is the vendor just working to sell a $32 chunk of metal?

If using a 13ci Ninja brand tank, you do not need anything special to install it on a QB79.  The standard issue tank block works fine and usually leaves 1/8" of clearance between the tank and barrel. 

Some other brands of 13ci paintball tanks are a little larger diameter and may not fit.

Dragons, tigers... one of those Asian motifs 

Thanks for the info, $30+ can buy a lot of pellets.

I noticed the vendor name was "blotted out"... did I unknowingly violate a forum rule?... no vendor references?  Or is there another reason?

Many thanks to all, have a happy Hump Day!

Steve

[sr1sws]

And another questions... how loud is the QB79 running on HPA?  As loud as a Disco without an LDC?

Steve

[rsterne]

At similar power levels, the report is about the same as a Disco without LDC.... but it can vary quite a bit depending on how it's tuned, just as a Disco is about twice as loud on the first shot as the last shot....

Bob

[sr1sws]

At similar power levels, the report is about the same as a Disco without LDC.... but it can vary quite a bit depending on how it's tuned, just as a Disco is about twice as loud on the first shot as the last shot....

Bob

Thanks Bob.  Just trying to figure the TCO of going this route.  Looks like the Umax compensator would be more affordable than a TKO Level V for a QB.

Thanks for publishing this route (QB79 + Ninja SHP).  If I had seen this a few weeks ago, I might have gone this route rather than my Disco... but maybe I'll do both.

Have a great day!
Steve