Talk me out of QB79 on Ninja HPA tank

[cclingma]

Couple newbie questions about this

1.  I assume you have to degas tank every time you go into the valve?

2.  If 1 is correct, how do you degas?

3.  Can I drill hammer for cock on opening with a good new bit  in drill press or does it require end mill?

4.  Can I drill end cap for RVA if desired with drill press?

[sr1sws]

Couple newbie questions about this

1.  I assume you have to degas tank every time you go into the valve?

2.  If 1 is correct, how do you degas?

3.  Can I drill hammer for cock on opening with a good new bit  in drill press or does it require end mill?

4.  Can I drill end cap for RVA if desired with drill press?

Others should weigh in too, but I'll share my understanding.

1. Yes
2. CAREFULLY, slightly unscrew the low pressure burst disk and bleed the air out.  I've done this, it works.
3. I've READ that it's almost impossible to drill due to it's hardness.
4. I don't actually know, but I would think so.

Steve

[BigTinBoat]

Couple newbie questions about this

1.  I assume you have to degas tank every time you go into the valve?

2.  If 1 is correct, how do you degas?

3.  Can I drill hammer for cock on opening with a good new bit  in drill press or does it require end mill?

4.  Can I drill end cap for RVA if desired with drill press?

1- NO, you do not have to de-gas the tank - just unscrew it - I usually unscrew 1 full turn from fully seated (this releases the pin valve allowing it to close) and then dry fire 3 or 4 times (until there is no pressure on the connection) and it is easy to unscrew. If you feel resistance on the connection when unscrewing, dry fire a couple more times and you should see the pressure drop off the connection.
2 - N/A
3 - I drilled my hammer for my 78 with a drill press - if you take a grinder and just put a small "flat" where you want to drill this should put you past the case hardening and it should drill pretty easily.
4 - I drilled my end cap with a drill press - the harder part is tapping w/o breaking the tap, go slooooooow and use tapping fluid

[cclingma]

Great responses.  Thanks!

Would you guys recomend 1200psi regulator or 1500psi?  Looks like 55fps or so difference in .22 and a few extra shots at the lower setting.

[sr1sws]

Great responses.  Thanks!

Would you guys recomend 1200psi regulator or 1500psi?  Looks like 55fps or so difference in .22 and a few extra shots at the lower setting.

I'm using the Ninja Pro V2 SHP which is factory set to 1100psi with my .177 QB79.  Works great, but I was only looking for about a 12fpe gun.

Steve

[Ribbonstone]

3 thoughts, and mostly folks reject the idea, as they are more power-hungry.


Thought #1:

I post this every so often just to remind folks that there is more than one reason to HPA a .22 QB79.

You can, with no major shop tools, convert on to run on HPA and manage +200 12 foot pound shots per tank fill.  Now that energy level is pretty easy to reach on co2, but with HPA would be pretty independent of seasonal temperature changes.

Idea is to have a short barrel and only let out a little “blip” of air per shot to keep it at 12 foot pounds.  That’s about the same speed/energy that a well pumped up Benjamin (312/342/392) MSP manages and generations of folks have used those for hunting.

But it is ugly:



Found it easier to manage that trick with 850psi out put. Even though you have to release a little more air volume per shot,  you get 2150psi with of air (in a 3K fill on a 13ci tank) for regulated shooting.


When I set up an AR2078 for 12 foot pounds, could only manage 160 shots per fill.  Might be that more could be eeked out, or it might be that getting a .177 up to 12 foot pounds just takes more air than getting a .22 up to 12 foot pounds.

(As an aside: getting a 5,, up to 12 foot pounds petty much split the difference between the .177’s 160 and the .22’s 205, by getting  180.)



Thought #2:

Had been running 4 HPA converted QB’s for about 6 years.  Have (oddly) found that the regulated bottles have all given problems at about 5-6 years use.  That’s a pretty long time., but it’s pretty predictable.   What goes  is the odd-sized o-rings on the regulator piston.  Could be use-cycles, but it appears to just be age (and age under a compressed air/oxygen environment).




Expect to rebuild the regulator about every 4-5 year.  Good news is that a rebuild kit is about $11-12.  BUY ONE when you order the bottle.  Just keep the rebuild kit in a dark drawer in your climate regulated house (so sunlight and excessive temps don’t degrade it) and it will get good-to-go when you need it.

Thought #3:


I’m lazy in summer.  With no game to hunt, am converting my AR2078 HPA back to co2. Have some 3.5oz.co2 tanks, which are a little smaller/shorter than the 13CI HPA bottles. So long as it’s warm outside and there are not game-critters (legal) to hunt, am going to just use co2 .  Might see a few out-law tweety birds fall, but so long as I’m not hunting furry things, I’d prefer co2.


So you pretty much “pays yer  money n takes yer chances”….high power for fewer shots, low power for a lot of shots.

  If there were my only air-powered rifles, I’d probably take the first (high power).  As I do have some PCP’s, am keeping them at the 2nd (lots of uniform shots).

[cclingma]

Thanks for keeping the info coming.

Funny how predictable I am.  I started reading up on these Qb conversions a few months back.  The very first thing I thought was "dang, that's some pretty impressive energy from a little budget gun."  I went all wide eyed and power crazy and wanted to go 1500psi and cut that valve down to a fraction of its original size.  I'm still kinda there to be honest.  I think I need two of these guns.  One C02 for plinking up the yard and one maxed out HPA for long range and tree rats.

My situation is a little different.  I have five vintage pumpers, one gas piston, and my Marauder pistol that in reality all make very similar power.  I'm wanting to break out to a little higher power but most of the hard hitters get so big physically that I loose interest.  Seems I could really enjoy QB on HPA.  From my point of reference, 27 or so ftlbs is a hammer.

I'm torn, keep it modest or mash the throttle to the floor and expect poor fuel economy and bald tires.

[rsterne]

I get 80 shots at 25+ FPE on 1200 psi with my QB79 with Stage 2 (shortened and hogged out) valve....



and it shoots like this at 25 yards.... Seems like the best of both worlds to me....



If you need more power, start with a QB78.... If you want less, dial down the pressure and hammer strike to suit your needs....

Bob

[SpiralGroove]

Hey cclingma,
Keep in mind, my QB79 (.22) has been on backorder for almost 2 months now .  So there maybe a substantial wait ahead once you pull the trigger.  It seems the QB79 in .22 cal. is the ideal way to go on the QB's, especially if you intend to do the work yourself and hunt.  I think the QB78 or QB78D requires considerably more work and expense.

I think the QB79 is a great looking package (with all do respect to Ribbonstone).  My Hatsan AT44-L / Galatian look fantastic, but a 9+ pound gun loses its luster when you've been carrying it in the field all day









When it arrives, my Goal with the QB79 (.22), is to best rstern's 80 shots per fill @ 850 fps using JSB 15.9 gr.
God knows I can't outshoot the Dominion Marksman

Good Luck ............ Kirk

[cclingma]

Bob, I almost can recite your $200 PCP post.  Thanks for taking the time to share all that and for posting here.  I think I read your Ninja is the one sold as 1100psi but measures 1200?  Are all the 1100s closer to 1200psi? 

SpiralGroove, I thought that other guy had Qb79 .22 available but just checked, sure enough he doesn't.
May have plenty time to stew on this.  Actually have one of my bows for sale and was going to jump in when it sells.

[rsterne]

I have no idea what "most" of the SHP Pros are, but mine was supposed to be 1100 and was just about bang on 1200.... on two gauges....

Bob