QB79 Ninja - The $200 PCP

[Buldawg76]

Bob
Very clean and secure for sure and only one set of extra threads to cut, I like it.

Always good designs for sure.

Mike

[Bryan Heimann]

Thank you

[wll2506]

I would think the warning is a just a CYA for the lawyers, because CO2 at 120*F reaches 1900 psi.... The biggest problem with the stock QB tank block is that the screws are soft, and too close to the end of the tube.... The JDS block moves them further from the end, and if you use high-tensile screws is a much safer arrangement.... One thing that concerns me slightly is when I see guys using the stock QB tank block in a QB78 (or Crosman) tube without inletting the stock for the block and using the two side stock screws as used in the QB79.... Since I am aware of one QB79 tank block that pulled out of the end of a tube (when not in a stock) by shearing the screws and nearly ripping the holes out, at only 2600 psi.... That tells you what the safety margin is at 1800 psi.... less than 1.5:1.... It must be a bit better with the stock screws in place, no?.... I would not recommend even removing a QB79 action from the stock while pressurized....

Bob

Bob,

That is exactly why I bought some high strength alloy screws and will install the as soon as my pressure in this tank runs out...I bought 4x .7 x 10mm long screws, they may be a little long but I can grind them down !

wll

[Buldawg76]

Can anyone tell me if the barrel on the QBs and the FDAR PCP 60C are the same and interchangeable between the two guns.

I have a LW 177 cal barrel for a 60C that if my new QB is not a shooter I would like to know if they could be swapped without modifications.

Mike

[nervoustrigger]

I can't answer your question in a detailed manner but I took this picture for some guys in chat a few months ago:

[Buldawg76]

I can't answer your question in a detailed manner but I took this picture for some guys in chat a few months ago:

Jason
Its a Gen 1 barrel so from the pic it looks promising as a drop in swap as the loading shelf may be a bit short but I can make a tray to take up the space.

Thanks Mike

[rsterne]

You probably don't need to extend the loading tray.... the bolt probe probably covers the gap at the back....

Bob

[Buldawg76]

Bob
I will know soon enough since my QB will be here tomorrow. But I am going to enjoy it some with CO2 first and then install my 60C fill fitting and try it on 1500 psi HPA before I start my conversion to the bottled HPA FT gun.

Mike

[pllagunos]

I believe they're both 4mm.
 - The air cylinder screws use an Allen Wrench.
- The Stock screws have a round head and take a Phillips driver.

I usually buy them longer than necessary, say 7mm/10mm in length, and grind down to fit.

Home Depot is your best bet

That's weird, mine has standard phillips screws.

So, they are 4mm x 10mm and replace the stock screws?

Thanks

[nervoustrigger]

From the factory, I'm accustomed to seeing Phillips heads on both sets of screws going into the tank block.

Both are M4-0.7 as previously stated.

8mm length works great for the ones passing through the air tube.

10-12mm length is good for the ones passing through the stock.

[Buldawg76]

I am thinking of going to 8-32 or 10-32 allen screws countersunk like the Prod and Mrods use to greatly increase the loaded area of the screws with either three screws or 4 screws with two on either side in front and between the o rings on a 2 o ring block or like Bob did with the cross pin and top screw to secure the pin.

Way over kill I know but I like to feel safe while shooting also.

Mike

[soarwitheagles]

Awesome thread here.  Thanks for all the info.

I read through most of these posts, but still am not sure if I can do the mods myself.

Will I need any machine shop tools to accomplish these mods?

Also, can someone tell me the exact items I would need to purchase  and where to purchase them to complete the mod safely?

Thank you,

Soar

PS We have tons of Big 5's near us.  So I am keeping my eyes peeled for a good deal!

[Buldawg76]

Soar
If you read this thread closely all the info you just asked about is in it and no you don't really need machine shop tools to do these mods but they do make it easier. I have only a drill press and dremel at home but do have access to a buddies machine shop at his house.

Got my new QB 78 Thursday and have been playing with it some in stock form and so far on a 50 degree day with the 2 CO2 powerlets it shoots JSB 10.34s at 600 fps and 8.44s at 625 fps for a total of 85 shots. I have removed the open sights and added a LDC and polished the trigger sear contact points and adjusted it for a nice light and crisp release and installed a 3x7x32 hawke AO scope on it for some grouping tests to see if it needs the LW target barrel put in it when I start my mods. I have the tank block and bottle on its way so after some further testing the conversion to HPA will begin. 

I am going to shoot it some with my 60C fill fitting in place of the CO2 cap so I can see just what it does at different pressures of HPA to get a better idea of just how far I need to go to achieve my goal of 900 fps with JSB 10.34s for FT matches in the hunter class.

Mike

[Buldawg76]

You probably don't need to extend the loading tray.... the bolt probe probably covers the gap at the back....

Bob

Bob

With gun in hand I believe you are correct in that the probe will cover the space behind the loading tray without issue with the LW barrel.

Mike

[SpiralGroove]

Hey Mike,
Keep us posted on your progress .
If you get a normal QB barrel, you shouldn't need the LW replacement.
However, for use in FT, maybe it would give you a little more accuracy.  Unfortunately, the LW barrel likely costs almost as much as the QB itself

[Buldawg76]

Hey Mike,
Keep us posted on your progress .
If you get a normal QB barrel, you shouldn't need the LW replacement.
However, for use in FT, maybe it would give you a little more accuracy.  Unfortunately, the LW barrel likely costs almost as much as the QB itself

Kirk

Scoped the gun last night and shot for groups today and am very pleased with its accuracy at least to 25 yards so may try the LW barrel just to see if it improves any. I already have the LW barrel and it only cost me 40 bucks from a fellow FT member so cost is not the issue. Here is a picture of the target at 25 yards and the flyers are me pulling the shots but there are 5 shots grouped within a 3/8" CTC group so its a shooter with the barrel it has now.

Mike

[SpiralGroove]

Mike ,
It will be interesting to see how much more the LW barrel can give you?

[Buldawg76]

Kirk
I agree but that will come when its apart upgrading to the bottle kit since I only want to take it apart as little as necessary. I know a barrel swap is pretty easy if I am correct in its only the barrel band and set screw on top of breech that needs loosened/removed to slide the barrel out and in.  I have never had these apart yet so if I am missing a step please let me know what is required to change out barrels.

Mike

[SpiralGroove]

Hey Mike,
That's it ............. not that hard. 
Yeah, I try NOT to take apart my guns too much as it becomes a whole day affair.  Replacing o-rings, lubing, bluing, or losing parts.

My shop bench is very messy after making my last LDC.  I don't dare do anything until the whole garage is cleaned and tools found .

[Buldawg76]

Kirk
I thought I was bad about tools and parts on my workbench but now don't feel so bad since I have good company I see, LOL.

The funny thing is being a mechanic for 45 years and even though it looks very much the same I know exactly where every tool or part is on the work table. My bulk amount of tools are in the three tool boxes I have very organized, but the ones I tend to use most everyday just never seem to make it back into the boxes for long enough to be worth the effort to put them up and get them out.

It keeps my grandkids from messing with them since they cannot put them back just how they found them so that I don't know they were playing with them so there is some method to my madness, LOL.

Mike