200 BAR / 2900 PSI gun

[Infernal Maveric]

OK...it's with a VERY light projectile (hollow foam maybe?) but Mach 2 seems to be reachable with 1" and 1/2" pipe and a light piston.

I'm starting to get exited

[Ragnarok]

It's know that GGDT has high errors at "extreme" conditions, and I'd say this was probably one of those times.

[Infernal Maveric]

Damn I completely forgot about the bugs in the higher end of the pressure scale with this program.

Would a burst disc or piston be a best for these sorts of pressures?

[POLAND_SPUD]

Infernal Maveric u don't need 2900 psi - try with 1200 psi

You can get that speed (1500 fps) with 1200 psi - at least according to GGDT. U don't need 0.5 inch barrel at all - an airsoft barrel would be enough for such light projectile.

It shows 800 m/s with burst disc at 1200 psi.... > 2 mach

don't get me wrong really i know it's your project and you can do whatever you want to... but tell me how many spudguns operating at more than 500 psi you can find here ?? very high pressure = machined parts, finding a pump or using a tank, costs, time and effort...

ok let say that u can get 2 mach with 1200, but keep in mind that BBs would slow down considerably 10 m from the muzzle ( ggdt estimates 100 m max range and it would take 4 second before a would BB hit the ground )
think over this whole idea... Is it really worth it for you?

[Ragnarok]

Mach 2 is utterly impossible without shock heating, you couldn't get more than about 500 m/s with air even in a frictionless barrel.

In a barrel with friction, more than Mach 1 is hard but that those pressures, achievable.

I also think the GGDT range prediction is a little off, it's not much good at high velocity and low mass guesses.
Feeding the numbers into the range calc I'm writing ATM, I get a slightly higher number (110-120m), but taking 5 seconds to target.

[jackssmirkingrevenge]

If you're using high pressure, the advantages are best seen on a smaller scale so I would definitely go for either a high powered single shot "rifle" in 0.177" of 6mm calibre with a stout piston or triggered burst disc (look what I hade done with 400 psi ) or more likely a cloud BBMG like he one BTB is building.

Instead of a pump, have you considered a SCUBA tank? You can get a cheap one off eBay (make sure it's certified though) and refilling it will only set you can a few quid, it will save you hours of pumping.

[Infernal Maveric]

From what you guys have since my last post, I would probably make a BTB styled BBMG and run it at about 1000PSI inside a steel chamber. The air rifle pump I am getting isn't pricey at all (for what it is).

I may also build a single shot triggered burst disc gun at a bit of a higher pressure to get higher velocities.

[ALIHISGREAT]

From what you guys have since my last post, I would probably make a BTB styled BBMG and run it at about 1000PSI inside a steel chamber. The air rifle pump I am getting isn't pricey at all (for what it is).

I may also build a single shot triggered burst disc gun at a bit of a higher pressure to get higher velocities.

the downside of building a bbmg BTB style with a high pressure air supply such as co2 or a hpa chamber is that the suppy is not consistant, the pressure will drop constantly so to make the air last longer you should use a higher pressure chmaber and a regulator.

Personally i think the single shot will be far more awesome because of the awesome power it will have

[Infernal Maveric]

The reason I'm kinda against having it single shot is because for 1 shot i will need to pump for quite a while, where as with a regulated BTB-BBMG I can have many shots fired from one fill.

[jackssmirkingrevenge]

the pressure will drop constantly

As we know a BBMG still gives reasonable power at 100 psi - besides, if you're shooting at something with a 1000 psi BBMG, after a couple of seconds there isn't really going to be much of it left, long before you run out of air

[ALIHISGREAT]

the pressure will drop constantly

As we know a BBMG still gives reasonable power at 100 psi - besides, if you're shooting at something with a 1000 psi BBMG, after a couple of seconds there isn't really going to be much of it left, long before you run out of air

yeah i supose, but what if you want to carry on the carnage on the target next to it? you won't have much air left...

[jackssmirkingrevenge]

but what if you want to carry on the carnage on the target next to it?

Time to get pumping

[Infernal Maveric]

LOL Jack!

Anywho, I still need to get the air rifle pump, as without that, the whole project ill go under. But I know that if i get the pump, that I will build one hell of a decent BBMG with machined parts and all shinyness!

[ALIHISGREAT]

but what if you want to carry on the carnage on the target next to it?

Time to get pumping

Are you making fun of my problem? i have a bmi of 500

[jackssmirkingrevenge]

Anywho, I still need to get the air rifle pump, as without that, the whole project ill go under.

I had been contemplating getting a pump for my PCPs but in the end went for the SCUBA tank and never looked back, it's incredibly more convenient - and if you compare the price of a
new pump to a new 3 litre 300 bar SCUBA tank, it's only a few quid more expensive. Of course it's important to have a dive shop nearby, if not then go for the pump or it will get expensive, but otherwise, go for the the tank.

Are you making fun of my problem? i have a bmi of 500

In that case, Dr. JSR recommends you build a punkin chunkin size cannon and fill it with a shock pump