SpudFiles

Alrighty I'm lookin to make 2 nade launcher's outta scratch(or close to it) because its cheaper. All need to be kept under 230fps and need to be powered by Cº2

The first I'd like to be a bolt action single shot. It needs to be long to hold the groupings tight and maybe get a little better accuracy. However, it doesnt need to be a beast, I'll still be using them for moble squads. I also need a way to attach a bi pod and sling into it. I figure I'll just get some metal tape and strap on a 2x4 then drill that for whatever is necesairy. I'll prolly just get a cheap bi pod with a swivel stud and get another one and use those. It'd be managable to be powered by 12grams and tanks.

The other I'd like to be short and have a breach action similar to the M209 that would have no problem strapped to the underside of a barrel. This would/should be powereed by 12grams and a quick change adapter would be very much apreciated.

The first needs to have good and predicatable groupings at 80yards and the other needs to be close to 60, but because its so small range could easily be comprimised for practicality.

...you're talking a homemade rifle for paintball? dont try it, its too unpredictable to keep it at a reasonable FPS, indirect fire weapons are fine, like mortars and such though

huh y does yours have to be kept under 230 fps at my paintball range the regulation is 300 fps i don't think that my gun would even get below 230 fps unless if i gave it a realy crappy spring or something???

i just got my stabilizer, will that help speed consistancy??

No no no, this is a nade launcher not a paintball gun. 230fps is the 'alterative weapon' limit.

"too unpredictable"
Simply put, this is false. Pnematics (with a automatic valve of some-sort - not a manualy opened ball valve) are quite consistent... I won't go as far as to say "more so" than a comercial product, but pretty good... within 10% each time, certainly. Heck, metered propane launchers are that reliable.

If you are scared of a regulator failure filling your chamber to 200 psi, and then you putting a hole in someone's APC, install a saftey pop-off of the appropreit pressure rating.

The main problem is that you need a pretty short barrel to get legal speeds... if you bring a cannon with a 6' barrel, you will blow holes in things.
But why would you want to use a homebuilt [paintball gun]? It's ROF is abysmal, accuracy might be lower, and it's probably going to be louder.

lets see y a homemade one...
my parents wont let me have a real one, thats one of the reasons i got into spudguns, also if a semi-auto is made right, it can be really kool for show.
of course nobody really wants to use a homemade pb gun in a real game agaist ones that are designed by engineers.

i do not think propane launchers are constistant btw, also any pneumaticly actuated air gun will have the "human factor" as in the speed ur pressing a blowgun, things like that, something electronic will be better but weaker, so maybe a 1" valve fired with a tiny electric valve. also other bells and whistles are useful, like a overfill alarm when it is not going to blow but shoot too fast, can also open a switch so it wont fire(good idea). i've also been thinking about a built in chony or rof counter, but quite expensive that will be.

Fairly consistent; The data from ssb73g's tests (which are designed to maximize the shot-shot difference) indicates that you typicaly have a standard deviation of about 20 feet/sec. If I remember right, this means that 65% of his shots where within 20 feet/sec... or roughly 4.5%. Fairly good.
Incidentaly, his QEV tests had a StD of about 6... 1.5% - really good, considering his pressure is only regulated to 1%

As to combustions, lakte tests seem to have a StD of about 6 (gasket slugs - russets where like 20!)... out of 600 feet/sec - 1%! Tennis balls arn't quite as good, but still quite good.

Maybe it's time to re-think (the stereotype of) pnematics as more consistant.