SpudFiles

Rifle Specifications

Building Material: Scheduled 80 PVC
Chamber Length: 16"
Chamber Diameter: 2"
Chamber Volume: 50 ci
Barrel Length: 40"
Barrel Diameter: 1"
Loading Style: Muzzle Loader
Fill Valve: Schrader Valve
Power Source: Compressed AIR
Trigger Valve: Spring Action 1" Brass Ball Valve
Opening Time: 15 miliseconds
Average Working Pressure: 200psi
Maximum Pressure 275 psi
Muzzle Velocity:
994 fps with 5 gram bolts with muzzle energy of 170 ft/lb
1034 fps with 3 gram paintballs with muzzle energy of 133 ft/lb
1100+ fps with 0.25gram bb buckshot with muzzle energy of 33ft/lb

Well basically i was obsessed with metal designs before this but after my Scheduled 80 Pvc rifle i was very impressed with the performance it had. It not only outperformed my metallic cannon but it was also easy to join, lightweight, and cheaper to build. The building material used is a 2" Sch 80 pvc pipe instead of regular Sch 40. Although it was hard to find, i managed to get some for under $70 for the entire gun. I purposely used Sch 80 instead of Sch 40 due to the pressure rating....Sch 40 is not safe above 200, while its maximum operating pressure is 280 psi for 2" but Sch80 its max pressure is 400 psi so i could use pressure to abt 200-300! I combined these pressures with a long barrel and decent volume of 50 ci and chronographed it ...the results were up to the mark...i got 942 fps with a 5 gram bolt!!! Which went right through 3/4 inch plywood and chipped the wall behind!

Its performance is way better than 90% of air rifles in the market today...and its easy to make, lightweight, inexpensive and very efficient! And I would say rather than using metal one should use Sch 80 or Sch120 Pvc as the pressures that Sch 120 can hold are 500 psi for 2" which is way high for plastic and hardly anyone these days goes upto that pressure!

scheduled 80 isn't a pressure rating but the wall thickness, just to make sure did the PVC say nsf-pw then the pressure rating in psi, or pn and the rating in bar?

anyway i still don't recommend using any PVC part at pressures above 120, they might be able to handle it but if it did explode the pvc will make lots of very high speed shrapnel. That's why there high pressure cannon made of PVC.

Other than that look very well built except for the fill valve, you should have put it on the side where it would go though two layers of PVC.

instead of 2" PVC you could have used 1" iron pipe and higher pressures - high pressure is not a problem at all for a single shot gun

The Standard Ammo: 4 g Nuts

interesting... are they stable in flight?

Crna Legija wrote:scheduled 80 isn't a pressure rating but the wall thickness, just to make sure did the PVC say nsf-pw then the pressure rating in psi, or pn and the rating in bar?

anyway i still don't recommend using any PVC part at pressures above 120, they might be able to handle it but if it did explode the pvc will make lots of very high speed shrapnel. That's why there high pressure cannon made of PVC.

Other than that look very well built except for the fill valve, you should have put it on the side where it would go though two layers of PVC.

maybe ur right but as of now none of my cannons has failed on me so i feel quite comfortable with Sch 80 Pvc! I have attempted a metal build before but the fittings and working with metal machining is a lot harder than pvc!

For an improvement or gk....is it good to have a higher pressure or higher volume?? If high pressure gives better performance then ill use metal config otherwise if low pressure high volume is better then ill use PVC config! Also if u have a good config for 4g marbles at 900+ fps plz suggest....all suggestions appreciated!

High pressure is better. Nice cannon... Don't use such high pressure.

So With a 20 cubic inch metal chamber with 200 psi would i expect better results than a 40 cubic inch metal chamber at 100 psi?




This is a reading of 0.2 gram bbs at 220 psi!

Correct.

It is impossible to get that velocity using air. It is most likely a reading of the muzzle blast. Sorry

Gun Freak wrote:Correct.

It is impossible to get that velocity using air. It is most likely a reading of the muzzle blast. Sorry

Whats muzzle blast???

The propellant gas expanding out the barrel. Move the chrony farther away from the muzzle.

oh ok.......ill update u on a new reading tomorrow probably!

I agree that the velocity figures are unrealistic, there is obviously some interference with the sensors from the muzzle blast. Still, very good effort, though it can use some polishing.

You should think about spring-loading that ball valve for better performance and consistency. Another way of improving performance would be wedging a burst disk between the barrel and the valve, looks like it would be an easy fix.

So With a 20 cubic inch metal chamber with 200 psi would i expect better results than a 40 cubic inch metal chamber at 100 psi?

What I always dig up in this case, have a look at this data for a virtual launcher modelled in GGDT - in each case, we're talking about the same quantity of air, but in a reduced volume and therefore at higher pressure.

(chamber is of constant diameter but different length, projectile size, weight and valve flow/barrel length are constant)

20 inch chamber at 50 psi - 406 feet per second

10 inch chamber at 100 psi - 537 feet per second

5 inch chamber at 200 psi - 684 feet per second

2.5 inch chamber at 400 psi - 830 feet per second

1.25 inch chamber at 800 psi - 958 feet per second

0.625 inch chamber at 1600 psi - 1006 feet per second


As a footnote crop! aaaagh!

LoL....Feet Per Second !!!!

Ok People taking suggestions from the above comments i have decided to remake another model!

It will Be Of the Following Specifications:

Construction Material: Sch 40 Galvanized Metal Pipe
Chamber Length: 6"
Chamber Diameter: 2"
Aprox Volume: 25 Cubic Inch(Half Of This Cannon)
Barrel Length: 40"
Barrel Diameter: 1"
Pressure(Working): 300+ as the full gun is of metal
Max Pressure: 500 psi as i dont want my fridge compressor to blow

SO do u think the changes in the desing will improve or hurt the performance of the rifle??

It will definitely be stronger, but I wouldn't use a ball valve...

Gun Freak wrote:It will definitely be stronger, but I wouldn't use a ball valve...

Agreed, a manually operated ball valve is inconsistent, makes it impossible to aim and isn't the best performer. Adding a simple spring and trigger will solve that.

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Ok guys i have completed my design for the metal gun ...i will upload some pics for it ......next thing to do is make a spring action for it!