Hybrid handgun with rupture disc

Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
hectmarr
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Mon Jan 15, 2024 4:06 pm

I had this project in mind for quite some time, and I have finally finished it.
This is this .22 caliber pistol that fires common pellets, associated with a rupture disc. The advantage is that the weapon can be supplied in the same way as a common, commercial compressed air gun.
It has an inverted lock, for this purpose.
It's a pump gun. With 9 pumps it has 10X which is the pre-compression pressure of the hybrid.
The small air pump has a 17 mm diameter piston, and the butane dosing system is the one I usually use for these pump weapons.
The firing barrel is ribbed, 310 mm long, which makes it shoot with very good speed.
The lighter is a piezo electric and has a motorcycle spark plug to ignite the air and butane mixture.
The challenge was to include everything necessary on board a handgun. The small butane tank is on the inside of the handle, and is a conveniently modified asthma medication spray.
The main advantage is the ease of operation, and the very low cost of the weapon.
It has a single o-ring at the exit of the combustion chamber, and nothing else...
The pellets are attached to the 11 mm diameter rupture disc, so as not to have to load the pellet and then the rupture disc. It is two layers of thin aluminum foil.
The open sight has fiber optics for better viewing.
The pumping is with little force. I was unable to obtain a 19 or 20 mm tube for the air pump to improve the volumetric capacity of the air pump, and there was no alternative but to use a 17 mm tube.
The operation is in three parts:
1- Load a pellet/rupture disc.
2- Press the gas valve for 1 second.
3- Pump 8 or 9 times and you can take the shot.
A commercial silencer can be included that greatly reduces the sound. If this suppressor, it is quite noisy.
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mobile chernobyl
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Tue Jan 16, 2024 9:29 am

Very cool - I've often considered this same concept in a 1" -1.5" bore configuration (more shoulder rifle sized than anything) but using the piston valve hybrid design so I could use generic round ammo without needing to reload a burst disc every time (golf balls or similar lol).

Any idea of the muzzle velocity? If you're exceeding 700-800 fps (200-250 m/s) then this is very interesting - it seems like most compact PCP (and some CO2?) pistols are around that range right now with nothing (new) out there that is pistol sized, multi-pump pneumatic and similar velocity (That I have found).
hectmarr
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Tue Jan 16, 2024 10:58 am

I compared it to a commercial PCP pistol of the same caliber and they shoot the same. Two meters from the target, with the same 16g pellet, they pass through the two three cans of soup. According to the stopwatch of my friends who have the same weapon, it is around 700 to 750 fps with 130 bar in the tank. The manufacturer lies, when he claims 900 fps! I imagine that the difference in barrel length, 21 cm and 31 cm of my hybrid pistol, compensates for the lower pressure of my pistol and they remain the same. Of course mine only cost 30 dollars, and the other 450.... The pellet is loaded the same in both, only in the hybrid pistol, it goes with the small associated disc. It is a valve free gun!
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jackssmirkingrevenge
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Wed Jan 17, 2024 9:40 am

Excellent work as always, as I've said privately the fact that you've made it work consistently would be admirable even if looked like a bunch of random parts thrown together, but you've also managed to make it neat and stylish, kudos! The trigger guard integrated in the pump handle is really a nice touch!
mobile chernobyl wrote:
Tue Jan 16, 2024 9:29 am
Any idea of the muzzle velocity? If you're exceeding 700-800 fps (200-250 m/s) then this is very interesting - it seems like most compact PCP (and some CO2?) pistols are around that range right now with nothing (new) out there that is pistol sized, multi-pump pneumatic and similar velocity (That I have found).
There have been some developments, for example the Huben GK1 in 0.25 cal does almost 900 fps with 25 grain pellets for around 45 ft lbs, and it's a semi-auto with a 17 shot magazine, although that performance comes with a hefty price tag.
hectmarr wrote:
Tue Jan 16, 2024 10:58 am
According to the stopwatch of my friends who have the same weapon, it is around 700 to 750 fps with 130 bar in the tank. The manufacturer lies, when he claims 900 fps!
When velocity is the selling point they will test it with a ridiculously light pellet to be able to claim these figures, but it seems the general public is becoming a bit more educated about the fact that without knowing the weight of the projectile, velocity is meaningless, so it's becoming more common to see energy ratings being advertised.

Have you experimented with different strengths of burst disk? We have seen what a difference it can make in terms of performance.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Wed Jan 17, 2024 9:44 am

This would be the design of a cartridge containing the pellet, rupture disc and sealing o-ring, to introduce the pellet into the barrel and leave the cartridge in the firing position using a bolt.
Of course, for a single-shot weapon like this pistol it is not necessary, but if you need an ammunition magazine, it is the solution.
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Wed Jan 17, 2024 9:57 am

jackssmirkingrevenge wrote:
Wed Jan 17, 2024 9:40 am
Excellent work as always, as I've said privately the fact that you've made it work consistently would be admirable even if looked like a bunch of random parts thrown together, but you've also managed to make it neat and stylish, kudos! The trigger guard integrated in the pump handle is really a nice touch!
mobile chernobyl wrote:
Tue Jan 16, 2024 9:29 am
Any idea of the muzzle velocity? If you're exceeding 700-800 fps (200-250 m/s) then this is very interesting - it seems like most compact PCP (and some CO2?) pistols are around that range right now with nothing (new) out there that is pistol sized, multi-pump pneumatic and similar velocity (That I have found).
There have been some developments, for example the Huben GK1 in 0.25 cal does almost 900 fps with 25 grain pellets for around 45 ft lbs, and it's a semi-auto with a 17 shot magazine, although that performance comes with a hefty price tag.
hectmarr wrote:
Tue Jan 16, 2024 10:58 am
According to the stopwatch of my friends who have the same weapon, it is around 700 to 750 fps with 130 bar in the tank. The manufacturer lies, when he claims 900 fps!
When velocity is the selling point they will test it with a ridiculously light pellet to be able to claim these figures, but it seems the general public is becoming a bit more educated about the fact that without knowing the weight of the projectile, velocity is meaningless, so it's becoming more common to see energy ratings being advertised.

Have you experimented with different strengths of burst disk? We have seen what a difference it can make in terms of performance.
Thank you very much for your congratulations.
It has two discs which is what seems to give more energy, in this weapon and other similar long weapons.
For 10X and a .22 caliber, with three discs the power to pierce cans decreases and with a single disc, too. As I mentioned, this is for all weapons with a bolt and a rupture disc that fires cup-shaped pellets, of the same caliber, and that are around 10X pre-compression of the mixture.
The combustion chamber attached directly to the barrel seems to significantly increase energy due to the absence of dead volume.
Regarding your assessment of this gun, it works perfectly, I did not have a single failure in any shot, I just reduced the amount of butane, because with 6 ml, it has a small delay in firing when you press the lighter. With 5.3 ml, this delay no longer exists. :)
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Wed Jan 17, 2024 9:35 pm

Whoa, thats pretty amazing work. Very nice. I love the compactness of the whole thing. It's very clean.
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Thu Jan 18, 2024 10:32 am

Moonbogg wrote:
Wed Jan 17, 2024 9:35 pm
Whoa, thats pretty amazing work. Very nice. I love the compactness of the whole thing. It's very clean.
Thank you!! I'm glad you like this work.
quinn whitsitt
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Tue Feb 20, 2024 11:04 am

nice job
and i hope you all have a great day a great week and a great year!!!!
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