Spring Piston Rifle

[CpTn_lAw]

I see what you mean. However, i'd suggest he starts by doing a less complicated design before, avoiding problems we encountered. ( i had a 2L soda bottle blow up near my brother's head, or a slug from a hot glue piston shot at my foot at 120psi. )
The designs you built BTB were maybe inspired by others, but the final rifle is yours, and that's what makes it so damn nice.
getting pressure ratings out of your a** is not à road to walk on... Just judging by the wall thickness and/or material.

[DerpWithAGun]

Hey Guys,

I'm only making one air rifle. It will be a simple hammer valve, 600 psi, 700 fps, 5 shots per re-charge. Will shoot 4.5mm BB. Will be bolt action, breach loaded.

After I built it I will be moving on from my interest in air rifles.

I'm only building an air rifle because I can shoot it in the backyard without neighbors calling the cops. But my Uncle has a farm now and I'm going to be making some magic guns and shooting them there. I'll post pictures of the finished air-gun and then I'll be moving on.

Thanks everyone for all the ideas, advice and feedback.

[Zeus]

Derp, if you want some 4.5mm ID Al, let me know, I've got about 14M here.

And don't disappear either, I play around with magic guns, but I still like pneubmatics and hybrids.

And I'd advice editing your post, it's known as magic here.

[DerpWithAGun]

Lol I edited it.

Okay, I wont disappear. Where in Australia do you live? How much for 1M of the pipe?

Ill draw up one last design now and upload it here.

It's just, magic guns are more appealing to me than air guns. I like air guns, but they don't produce that epic smell and epic feel that magic guns do. That's why I want to make them.

[Zeus]

Central Vic and whatever it costs you to get it. I've got enough around and I can get it for $1 a meter.

I understand the appeal of magic guns, and I've gone there, but it's more worthwhile to wait until you can get a license. If you like the kick, get a 12GA coach gun. Heck, spend $40 and get a junior license and go to a shooting club, there's always people happy to take a new shooter under their wing.

Just ring the club first, or ask at a gun shop.

[DerpWithAGun]

Alright, maybe you could put the barrel on E-bay? I don't have a credit card so I'll have to ask mum for hers, and if I say to her that I'm giving some guy I don't even know my address she will have a fit! So E-bay would be the best way. I'll pay for shipping as well.

My mum and dad are going to let me join a club soon. Gonna get my junior license and stuff as well. I'm also joining Cadets so I'll get to shoot an 88 Austeyr.

Anyway, enough about magic guns, this is my very simple hammer valve design!.


Black: Steel, main body, barrel, ect.
Green: Spring
Pink: O-ring
Grey: Washer
Blue: Hammer
Red: Bolt

Trigger mechanism and pressure chamber haven't been drawn up yet.

[warhead052]

It's just, magic guns are more appealing to me than air guns. I like air guns, but they don't produce that epic smell and epic feel that magic guns do. That's why I want to make them.

Well if you are looking for the recoil, fill your barrel full of water. It will blast you back easily 1 foot.

[DerpWithAGun]

Well if you are looking for the recoil, fill your barrel full of water. It will blast you back easily 1 foot.

Depends what size barrel and how much water. I would want it to be able to shoot a pellet with water in inside the barrel and that probably wont work because your adding weight by filling the barrel with water, = lower FPS.

After I make this I'll be focusing on only making air shotguns. For shooting pellets I'll make a magic gun.

[warhead052]

Well if you are looking for the recoil, fill your barrel full of water. It will blast you back easily 1 foot.

Depends what size barrel and how much water. I would want it to be able to shoot a pellet with water in inside the barrel and that probably wont work because your adding weight by filling the barrel with water, = lower FPS.

After I make this I'll be focusing on only making air shotguns. For shooting pellets I'll make a magic gun.

Well I kinda meant only water for recoil, but I suppose you could use twice as much pressure to achieve the same velocity for the pellet while pushing the water out.

[DerpWithAGun]

I made a better design!



This design will be pretty easy to make if you understand it but there is a slight problem. Where the red arrow is, I can't think of a design for the breach where you load the projectile. I was wondering if anyone could edit my picture and add a design for the breach. I would appreciate it very much if someone could do so.

Thanks!

[DerpWithAGun]

Alright I edited my design and did some changes. I also made a design for the breach so no one has to edit it for me now. Tell me what you think of it guys, this will the final design that I will use.



Green: Spring
Black: Main body / Main internal parts
Grey: Internals e.g Bolt, Breach, Hammer
Yellow: Epoxy
Blue: Valve Stem
Pink: Sealing face / rubber

[DerpWithAGun]

Sorry, tripple post but I need to ask a question.

Does anyone know the maximum pressure that epoxy can hold? In my design I'm only using low pressure, about 700 - 1000 psi and I'll be making end caps for the pressure chamber and using epoxy to put them in place, no threads.

Also, I think the picture I drew above can be made into semi-auto mode in two different ways. I could put a strong enough spring at the sealing end of the valve stem. Then would cause the the striker, when it hits the valve stem to bounce back and re-cock itself. And by placing the notch on the striker in front of the bolt will also pull the bolt back to load another projectile. This would mean I would need to make the bolt out of a lighter material e.g titanium, aluminum, plastic.

The second way for it to be semi auto would be to not seal up the hole where the valve stem meets the striker. When the striker hits the valve stem the valve opens for a very short time. In this time the air will travel up the transfer port into the barrel and the projectile will be fired. As this is happening air will also rush down the valve stem and the pressure will push the piston into cocked position. Same concept as above with the striker's notch in front of the bolt.

As I was writing this, I also thought of this design being full-auto. It would not be a very fast ROF, probably as fast as a 12v battery mod to an automatic Nerf gun. Same concept as above with the air traveling down the valve stem only I would add a catch to the piston so when the air shoots the piston back it wont cock as long as I'm holding down the trigger. When I let go of the trigger the catch will catch onto the piston in cocked position.

Tell me what you think guys.

[Crna Legija]

Does anyone know the maximum pressure that epoxy can hold? In my design I'm only using low pressure, about 700 - 1000 psi and I'll be making end caps for the pressure chamber and using epoxy to put them in place, no threads.

All depends on how well you epoxy it in but anyway you do it wont last very long so your much better off using threaded fittings and pipe.

I could put a strong enough spring at the sealing end of the valve stem. Then would cause the the striker, when it hits the valve stem to bounce back and re-cock itself

That wont work it a spring strong enough to do that will be to much for the striker to open it in the first place.

The second way for it to be semi auto would be to not seal up the hole where the valve stem meets the striker. When the striker hits the valve stem the valve opens for a very short time. In this time the air will travel up the transfer port into the barrel and the projectile will be fired. As this is happening air will also rush down the valve stem and the pressure will push the piston into cocked position. Same concept as above with the striker's notch in front of the bolt.

That could work but will need to be tuned quite well for it to work well, that will be hard especially with epoxy construction

[DerpWithAGun]

Alright thanks for the info, so epoxy isn't the way to go I see? I hope the drill bits for making threads aren't expensive, especially for connecting the pressure chamber, that chamber will have a 20mm OD and 15mm ID.

Semi and full-auto were just thoughts. I probably wont do them anyway. My 3 main issues for this project will be the threads, barrel and cost.

[evilvet]

My 3 main issues for this project will be the threads, barrel and cost

I think you may have a fourth issue, the actual capability to produce anything even approaching what you are wittering on about. Enough already:

*1000psi held in by some epoxy
*"drill bits for making threads"
* try joining the Army Cadets with a criminal record thanks to your "magic" gun
* heat treated pressure chamber

etc, etc, etc, etc

Enough already

Read the posts, make a basic QEV, understand what WILL happen when you play with pressures of 100+ atmospheres and for everyone's sake, think about it.

When you are absolutely totally convinced that you have it all worked out, stop and think about it some more, then go and play Xbox for a while and LOL while ROFLMAO.