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High velocity BB rifle

Posted: Sun Sep 09, 2007 2:22 pm
by Infernal Maveric
This is a modification of my "QB" BB gun.
Chamber has been reduced significantly, as well as the pilot volume. To do the latter some bodging had to be done, but it holds pressure perfectly, and does the job I want it to.

Specs:
Barrel: 6.4mm Audi fuel line
Chamber: 15mm copper pipe
Ammo: 5.8mm BBs (0.12grams)
Valve: Detrol 1/2" QEV
Fill valve: Scharder
Pressure used: 300-400PSI

Enough with the numbers, onto the pictures.

Main gun.
Image

The rear of the gun.
Image

Comments/suggestions welcome.

Posted: Sun Sep 09, 2007 2:23 pm
by potatoflinger
That looks pretty nice, but what is that thing under the barrel in the first picture?

Posted: Sun Sep 09, 2007 2:38 pm
by NoXi
looks like a laser to me

Posted: Sun Sep 09, 2007 3:13 pm
by hi
i think that a QEV such as that one is only rated at 150 psi. thats what mine is rated to anyway. maybe its rated at 150 because they know that people like you take it to 300. :wink:

it looks good, but why do you have such a small chamber. do you get better proformance than with a big chamber at lower pressure?

Posted: Sun Sep 09, 2007 3:20 pm
by Infernal Maveric
Potato: Yeah that's a laser and a LED under the barrel. I use it to give a rough guestimate as to where the BB will fly at long(er) ranges.

Hi: The QEV is rated to 150PSI, but it's aluminium so I guess 400PSI is safe for that, but I'm not too comfortable taking it to 400 regularly, so 300-375PSI is what I shoot with.

As for the reason for the small chamber, is because my bike pump died on me, and I'm too broke to buy a new one. Performance wise I feel that the smaller chamber at 375PSI is way more powerful than my old chamber was at 120PSI or 200PSI (Max i charged it to with old chamber).

Posted: Sun Sep 09, 2007 3:22 pm
by windshrike
Beeea-utiful.
Now add a stock.
That would significantly increase the aesthetic effect.

Posted: Sun Sep 09, 2007 3:52 pm
by f.c
i wish i was able to create a gun like this. sadly my wallet is to light.

Posted: Sun Sep 09, 2007 11:58 pm
by Mitchza89
Thanks a really nice gun. Looks like BB guns are on the list of guns to make at the moment :D .

Posted: Mon Sep 10, 2007 12:21 am
by spud yeti
Great looking gun. As someone above said, a stock would increase its aesthetics dramatically and really be awesome. What kind of speeds are you obtaining from it?

Posted: Mon Sep 10, 2007 2:14 am
by Infernal Maveric
I have no idea about the speeds, as I don't have access to a chrony, and am too poor to even consider buying one. But there is a loud crack when the gun is fired and makes my ears ring sometimes.

I might add a stock, but it would be difficult to add due to the compacted rear section. But I guess I can give it a go.

Posted: Mon Sep 10, 2007 2:20 am
by jackssmirkingrevenge
Barrel: 6.4mm Audi fuel line
Well posh aren't we :P :D

Very nicely done, it's good to see people acknowledging that for small calibres, low volume high pressure is better than high volume low pressure.
Yeah that's a laser and a LED under the barrel
ripped off a cheap airsoft pistol no doubt ;)

Posted: Mon Sep 10, 2007 2:35 am
by Infernal Maveric
Jack: Posh as in using a mitre saw to hack it off from the carcase of a car that was saw at the scrap yard then yeah!

I figured that I can get more power from this set up than with my old set-up, and the only working pump I have now is a shock-pump or an air compressor, so the SP won hands down.

My little brother's BB-gun first had the later-dot on it...Until I stole it! :twisted: