I'm finally going to do it, QB78 PCP mod! progress log.

[Necrosis]

Right now I'm in the stage of drawing it all!
I finally decided on a design, it still needs to be a bit fine tuned, however most of the drawing part is done!

I will post some screenshots of the CAD model when I've completed the parts.

Just wanted to get this out.

[inonickname]

Erm..Congratulations?

(confusion)

[theBOOM]

Yeah.. what are you building?? some more detail?

[inonickname]

Well the QB78 is some chinese airgun, and it looks like he wants to convert it to a PCP.

Some more information would be nice. CO2? HPA? How many shots? Average velocity and energy? Weight after mod..?

[Ragnarok]

Sounds cool.

I have these ideas about "making the Crosman Nightstalker good". It would involve lots of modification to turn it into a full-on regulated semi-auto PCP.
It would involve getting hold of a rifled barrel that would fit it though, because they're sold as smoothbore in this country.

But as always with me, more ideas than money.

Best of luck. Don't kill or injure yourself in the process. Both are quite inconvenient setbacks.

[Brian the brain]

From what I've seen from Necrosis, he is very capable of modding a PCP.
He's more of an airgun guy that a spud guy anyway...


8)

[Necrosis]

Well here's a picture!


Also, I am building a 300 bar HPA conversion for a chinese CO2 Airgun, yes.

I will get a .223 barrel for it, I expect something above 90 footpounds from that.

[jackssmirkingrevenge]

I have these ideas about "making the Crosman Nightstalker good". It would involve lots of modification to turn it into a full-on regulated semi-auto PCP.
It would involve getting hold of a rifled barrel that would fit it though, because they're sold as smoothbore in this country.

Interesting project, a paintball bottle with a regulator would supply roughly the same pressure as CO₂ so not put undue strain on the components but obviously much more shots per fill and better performance.

I would keep the smoothbore barrel, who needs pin-point accuracy when you're throwing so much lead downrange Also, you could put a spring loaded tube magazine in line with the barrel feeding into the 12 o'clock position of the magazine, so as it rotates, it's being reloaded as well.

My Baikal MP-651K uses the same system, original rotary mag is 8 rounds but it can take 23 rounds in total, almost triple the mag capacity:

[Ragnarok]

I would keep the smoothbore barrel, who needs pin-point accuracy when you're throwing so much lead downrange?

It's not so much about throwing lots of lead downrange, but making something that could prove a respectable air rifle. Odd idea to have, I know, but I never said I was a sensible person.

Anyway, if my design brief was "put obscene amounts of ammo downrange without concern for accuracy", that's what my hybrid minigun plans are for.

[jackssmirkingrevenge]

Also, wouldn't you fall foul of home office guidelines with a semi with a rifled barrel with significant power? If I remember well the quirk of the law was that you could only get rifled semis in 22LR, hence the lack of autoloading airguns like the Monsoon, even on FAC.

[Gippeto]

The nightstalker is incredibly fun to plink with (cans and ranks of dollar store toy soldiers), beyond that...even with a rifled barrel and red dot, accuracy leaves much to be desired. It is also finicky with ammo choice(feeding/jamming), and uses the 88gram air source cartridge, which is costly. ($12.50+ tax)

Yeah....I've got one.

The QB is a different animal all together. A bit of a "throw back" to when inexpensive air guns were still made from steel and wood. They've earned a solid reputation, and can be modded "out the wazoo". I've been thinking seriously about acquiring one.

@ necrosis, how is the valve mounted on the qb, and do you have any links to hpa mods that haven't become bombs?

Any data on the material used to make the pressure tube? Or are you planning to not pressurize the tube?

Thanks.

[Necrosis]

@Necrosis, how is the valve mounted on the qb, and do you have any links to hpa mods that haven't become bombs?

Any data on the material used to make the pressure tube? Or are you planning to not pressurize the tube?

Thanks.

The valve will be fitted to the pressure tube with a threaded connection, the holes in the "action" Are there to mount the whole thing to the frame.

The pressure tube will be made out of 30x3mm precision hydraulics pipe.


Also I've seen quite a few QB78 PCP mods including this very awesome one:



A guy on the local airgun forum made that.

And I doubt it will turn into a bomb, we can hydro test stuff at work, luckily.

[jackssmirkingrevenge]

Also I've seen quite a few QB78 PCP mods including this very awesome one

Very impressive, gotta love a bullpup Is the magazine an aftermarket item or a custom fabrication?

[Necrosis]

I believe that one is actually aftermarket..
In fact..
http://www.archerairguns.com/QB-RIM1X-M ... brim1x.htm

[Ragnarok]

Holy crap, that used to be a QB78?

Also, wouldn't you fall foul of home office guidelines with a semi with a rifled barrel with significant power?

The best I know is this, from the Home Office website:
The Home Office regard self-loading or pump action rifled airguns as outside the scope of the Firearms Act, unless they are sufficiently powerful to fall within the category of a "specially dangerous" air weapon.

Rifled semis probably could be imported, but no RFDs are willing to try and find out.

...also, let's be frank, even if it were a problem it would be one of the least of the potential issues amongst what I have around.

Besides, I doubt that the idea will ever go anywhere. More likely, I'll put the time, effort and money into the semi-auto gauss rifle plans...