Pitbull 9, semi auto 9mm!,New pics/upgrades page 3

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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Sun Feb 07, 2010 10:30 am

jackssmirkingrevenge wrote:Wow.

Nice to see the culmination of all your efforts, I know how long you've been at this idea :) It's sexy in an AUG sort of way, I like!

Now lets see those action videos ;)
i think it has the look of a FAMAS :roll:

EDIT::
or even better, an L85
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Sun Feb 07, 2010 5:40 pm

POLAND_SPUD wrote:the point is that you don't need a spring there... remove it and check if it works
The spring was put in the QEV because everytime I hooked up the air or disconected it the gun would fire,another member sugested the small spring to stop this and it did...........
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POLAND_SPUD
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Sun Feb 07, 2010 6:49 pm

hmm I see.. putting a check valve somewhere between the pilot valve and the QC/shrader would probably fix this but I never bothered to do it

Though can't think of anything that can go worng in a QEV valve so I guess you might remove it and check if works better without it
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Mon Feb 08, 2010 4:20 am

I just cant see any problem with the QEV but the Poppet Valve feels a bit Notchy when you push the button so I went and bought a new one today. I have to test it out and spend the time fixing up all the bodywork I broke prying it apart to get at the QEV :roll: ..



EDIT: guns firing with new Poppet Valve but now another major problem!!!! the Steel BB detent wore through the aluminium barrel and fell through.I now have to go find a new barrel and start all over ARGHHHH!,going to have be stainless barrel this time= might change to 6mm barrel, cheaper ammo but wont be as much fun as firing the 9mm BB's.

I allways have trouble finding Stainless tube here in Australia, especially the correct size of the ammo= the barrel I had on this gun had a noticeable bit of blowby robbing much power.....
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POLAND_SPUD
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Mon Feb 08, 2010 10:09 am

try hydraulic tubing...
places selling spare parts for uhmm... hydraulic equipment, caterpillars and such should have them

I got 100cm length of 12 OD X 9 mm ID for a couple of $
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django
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Tue Feb 09, 2010 3:34 am

POLAND_SPUD wrote:try hydraulic tubing...
places selling spare parts for uhmm... hydraulic equipment, caterpillars and such should have them

I got 100cm length of 12 OD X 9 mm ID for a couple of $
I'll try that, I work for a company that repairs CAT Dozers etc but ANY cat parts or anything from Cat suppliers here is VERY expensive.The BB's I use are said to be 3/8" I measured them at work in mm and are 9.5mm, the bearing shop told me you cant get 9mm BB's!??,the aluminium tube I was using as barrel is (10mm ID,12mm OD) so I had 1/2 mm blowby .

Looks like my guns out for the count until I can source the correct parts?, its never easy here to try match up ammo with barrel ID without some blowby then you get the suppliers asking, what the tube is for? and you have to make up something as we cant say Oh its for a BB gun!, oh the joys of Australia.........
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Patto
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Tue Feb 09, 2010 7:47 am

The best place i've found for small cal. barrel's in aus are the hobby shops !!

Toyworld have from stupid small up to 1/2 " in brass and ally tube. Also there's H.E Supples Heres somefor everything barrels, plastic etc. :lol:

Im using 9/32 brass tube with 1/4" steel ball bb's that you can buy from the bearing shop for like 300 for $22 etc. not perfect but here thats not bad either :?

only thing is you have to set the brass tube centered in the middle of you outter barrel ~ No big'ge 8)

Nice gun man you've done a good job ! :salute:
Last edited by Patto on Wed Feb 24, 2010 7:11 pm, edited 1 time in total.
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POLAND_SPUD
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Tue Feb 09, 2010 1:24 pm

@django
hydraulic parts are quite expensive but tubing is usually quite cheap


herehere is a table with weights and dimensions of chromed steel ball bearings (size in mm, size in inches, weight in grams)

I considered using 3/8" BBs but I couldn't find 10mm ID tube - that why I used 9mm ID barrel and 8.731mm bbs


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Jack_Hogg
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Fri Feb 12, 2010 1:55 am

Where did you get that threaded pipe from?
I got mine from my education for free, but that was only one small tube :(
I guess I was very lucky to find ¾" threaded pipe that they wanted to throw away!
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Fri Feb 12, 2010 2:03 am

For this project I cast an epoxy barrel around some 3/8" O/D tubing, which was (obviously ;)) a perfect fit for the 3/8" BBs which seam to be the cheapest to obtain as they're used as slingshot ammunition etc.
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Fri Feb 12, 2010 3:59 am

Well I gave up trying to find a better size barrel for the 3/8" BBS and just reusing what I had,gun will be up and running again by tomorrow.my other option is to sleeve the barrel with hobby shop brass tube,Im going to try find some tomorrow that fits but I dont know how I'll make the Brass barrel stay in the Aluminium one without flying away when shot, glue??.

I tried to get footage of the gun in action but its useless, the wifes digital camera has no sound option when recording footage!? and footage was too dark for some reason so was useless :roll:
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rikukiakuchiki777
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Fri Feb 12, 2010 4:14 am

django wrote:I dont know how I'll make the Brass barrel stay in the Aluminium one without flying away when shot, glue??.
Slide it most of the way in, with about an inch or so still protruding out, then cover the remaining outside part of brass in epoxy. Insert the brass all the way into the aluminium while twisting it a bit to make sure the epoxy bonds to maximum surface area, then just wipe off the excess with a rag or something. Or you could do something similar with solder, but it would be harder to clean up any excess that fell into the brass barrel.
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Fri Feb 12, 2010 4:21 am

ohh BTW not to highjack this topic but since we're discussing ballz :D
I've just realized something:

I bought 8.731mm BBs from this guy clicky
(200 pcs for 12PLN, which is almost exactly 4$)

but he also sells 10.3mm BBs (170pcs but still for only 12PLN = 4$)

in case you don't get it... weight of 8.731 and 10.3mm BBs is 2.65g and 4.43g respectively... so 10.3mm should, theoretically, cost twice as much

(normally there is a direct relation weight = price)

anyway the other reason why I posted this is because people consider BBs to be terribly expensive...
there are shops here that charge ~5 $ for a pack of 10 BBs but if you spend some time looking for better offers you'll find them

it's the same with QEVs and other valves.. I've spent hours comparing prices and the difference in price can be as high as 40-50% for exactly the same product

also contacting people directly pays off... I sent an email to the guy selling BBs and I asked him ' would I get a discount if I order them in bulk ??' as it turned out the guy is trying to get rid of them as no one buys them so he promised a 30% discount
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Patto
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Fri Feb 12, 2010 9:32 am

a good way i found to center the brass tube is BOG!! cut 20mm section from your outter tube and fill them with bog , drill a hole center and then you have a couple spacers you can glue to the brass then slide in to the outter tube then grub screw the bog ..

Even better if you have a lathe then you could you plastic or something simular :)
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Fri Feb 12, 2010 10:04 am

lol, nice gun :D
and what are those cans on the floor?
Monster? :lol:
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