Spring Piston Rifle

jackssmirkingrevenge · Thu Dec 22, 2011 1:54 am

Zeus wrote:Fallout 3

Booooooooooo!

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DerpWithAGun · Thu Dec 22, 2011 7:36 am

Lol enough of the Battlefield 3 and CoD hate. Halo beats both of them anyway lol!

Just wondering guys, does anyone know the diameter of the piston's chamber in a spring piston rifle?

Don't know what design to use right now either break-barrel or under-lever, don't know which will be easier.

jackssmirkingrevenge · Thu Dec 22, 2011 7:43 am

26mm on my HW97K
22mm on my HW45

In both cases the spring is quite a powerhouse, nothing you could cock without a lever action.

Don't know what design to use right now either break-barrel or under-lever, don't know which will be easier.

Break barrel puts stress on the hinge point, contributing to poorer accuracy.

DerpWithAGun · Thu Dec 22, 2011 9:19 am

Thanks JSR I'm going to make my chamber 22mm outer diameter and 20mm inner diameter.

What cocking mechanism do you recommend then if break barrel is inaccurate? I'm trying to get this as accurate and powerful as I can.

I'm also looking on the internet to find out how I can hand rifle the barrel. Found this so far, don't think it is much use though:

And also JSR, could you please measure the length of your HW45's barrel and it's piston chamber?

Thanks!

wyz2285 · Thu Dec 22, 2011 10:01 am

If you have ways to get 1000 psi, lathe and mill...
Why not a PCP

you don´t need a big chamber, I found out even with a small chamber, at 600 psi, you get more than 5 shots easily with a hammer valve. PCPs look better than a breaking barrel spring gun, and longer barrel so better accuracy and power.
And if you use a gas ram piston, why? it´s already a airgun, why still giving more job to put a piston in there?
For steel BBs, rifled barrel make no difference comparing to a smooth bore, but with lead pellets it may help.

DerpWithAGun · Thu Dec 22, 2011 9:00 pm

wyz2285 wrote:If you have ways to get 1000 psi, lathe and mill...
Why not a PCP you don´t need a big chamber, I found out even with a small chamber, at 600 psi, you get more than 5 shots easily with a hammer valve. PCPs look better than a breaking barrel spring gun, and longer barrel so better accuracy and power.
And if you use a gas ram piston, why? it´s already a airgun, why still giving more job to put a piston in there?
For steel BBs, rifled barrel make no difference comparing to a smooth bore, but with lead pellets it may help.

5 shots ain't enough, then I have to pump it up to 1000 psi again and again. Stirrup pumps that go to 1000 psi are expensive and homemade ones don't reach 1000 psi. And it depends, what fps do you get from 5 shots, small chamber and 600 psi? I also hate the look of pressure chambers. I would have made a hammer valve with a coaxial style pressure chamber but that would mean the gun would have to be muzzle loaded. My aim is to create an air gun or spring gun that looks like a real firearm, without that ugly pressure cylinder. By "small chamber" what diameter and how long was it?

jackssmirkingrevenge · Fri Dec 23, 2011 2:16 am

I posted these elswhere:

They would make an interesting starting point.

I was also amazed by the proportions on the 1337 internals, in my view it could easily be made significantly more powerful:

DerpWithAGun · Fri Dec 23, 2011 2:47 am

Very interesting JSR! Did you draw these pictures?

I might actually use this design but I'll change it a bit more. I'll add a nice wooden stock, turn it into a rifle meaning it will have a longer barrel, and a longer pressure chamber meaning more power, accuracy and shots.
With that hand pump under the barrel, it gave me an idea. I could make the wooden stock, and a portion of the stock at the front will be on hinges and fold down similar to a double barrel shotgun except the hinges will be on the front of the stock and not the back. Just imagine the orange part that folds down on the picture is the stock. Or I can just scrap that idea and buy one of these monsters: http://www.ebay.com/itm/Benjamin-Hand-P ... 3f08a2de90 Only problem is I don't know where to get a schrader valve adapter for it or the fill valve that actually fits onto that pump.

I could even have a small enough air chamber to just hide it inside the stock itself. If I make a PCP I would only make it if I make sure it takes 2500 psi +. Anything less than that is not enough shots for me. JSR, what FPS and how many shots do you think I'd get with 2500 psi, 22mm OD air chamber, 40cm long air chamber and 4.5mm steel BB or .177 caliber pellets?

I would also change the bolt part and add a revolving magazine. The square shaped bolt from the L96 is so awesome! http://airsoft.tiger111hk.com/images/pr ... OD%206.jpg

Thanks once again JSR, I'll be using this design as a starting point.

wyz2285 · Fri Dec 23, 2011 5:49 am

homemade ones don't reach 1000 psi

WRONG!!!
by small I mean smaller than the pump, 1.5 cm OD and 20 cm long
Unless you make one like that crosman, breaking barrel airguns are ugly.

jackssmirkingrevenge · Fri Dec 23, 2011 6:33 am

DerpWithAGun wrote:Very interesting JSR! Did you draw these pictures?

Nope, Chuck Testa.

Some Crosman customiser by the name of Gil Irvin.

Only problem is I don't know where to get a schrader valve adapter for it or the fill valve that actually fits onto that pump.

http://www.ebay.com/itm/New-Paintball-H ... 4157e46aef

http://www.ebay.com/itm/Air-Fill-Nipple ... 3cc0164fd1

http://www.ebay.com/itm/G7-paintball-re ... 27c1932679

Major Collins · Fri Dec 23, 2011 7:12 am

jackssmirkingrevenge wrote: Nope, Chuck Testa.

your full of memes haha

@Derp you said you didn't want to be pumping in a earlier post , why are you going with a pcp pump and stuff ? you should be working on designing a leaver cocking mechanism

and i Second Halo and Fallout 3

DerpWithAGun · Fri Dec 23, 2011 7:35 am

It depends Major Collins, I've been told they are ugly, low powered, hurts your arm after cocking the gun over and over, crap accuracy unless you shoot pellets with a rifled barrel, piston chambers that are too large and look silly, Springers have recoil problems and the slightest movement when aiming can miss your target by inches, PCP are stronger, PCP is more accurate, PCP lookes better and the list goes on.

If I can get a PCP design that shoots 4.5mm steel BB at 750 fps I'm happy. But it also has to have 20 powerful shots per re-charge. I'm thinking of a 24mm OD pressure chamber that will be 60mm - 70mm long with a ID of 21mm that will hold 2500 - 3000 psi. I choose 4.5mm steel BB because they will be most available to me and a .177 caliber pellet is 4.5mm

I'm also thinking about integrating an air pump into it. Sam Yang Big Bore Air Rifle has 3 barrels. I could do this design and make the third barrel a pumping handle. Middle barrel the pressure chamber and first barrel.... well a barrel. http://www.airhunting.eu/images/htmlare ... 4_zm_4.jpg

wyz2285 · Fri Dec 23, 2011 8:48 am

Sam Yang Big Bore Air Rifle has 3 barrels

No, one barrel and 2 chamber

Fri Dec 23, 2011 9:56 am

I've been told they are ugly, low powered, hurts your arm after cocking the gun over and over, crap accuracy unless you shoot pellets with a rifled barrel, piston chambers that are too large and look silly

Hmm...I hope you don't mean my creation...
Although the crap accuracy is probably right...

homemade ones don't reach 1000 psi

No? Mine got significantly more...
( before the crappy checkvalve blew and the handle broke my upper jaw ans stripped my gums off...)

Just imagine the orange part that folds down on the picture is the stock

I would also change the bolt part and add a revolving magazine

.
Hmm..you just spoiled the surprise on two of my 3 next planned projects...

Are you sure you're not going for a stickmagazine fed forced blowback both semi- and full automatic too?

I like your ideas!!
Can I have them back now??

If you think pressure chambers are ugly...you should really check out G.L. Barnes designs.

Btw: 22 outer diameter and 20 inside?? And you want to use 2500 Psi?
I'd recommend using something with a lot more wall thickness as you also need to secure your endcap and valve and such in there..
This means either drilling through the tube OR threading it on the inside wich ..would just eat the wallthickness completely...

Zeus · Fri Dec 23, 2011 6:03 pm

DerpWithAGun wrote: PCPs are stronger, PCP airguns are more accurate, PCP looks better and the list goes on.

All truth, a PCP is easier too. I don't recommend a springer if you don't have decent metalworking skills, if you make a break barrel hinge just slightly loose, kiss goodbye to accuracy.

With a normal rifle, the rifle has enough mass so you don't feel much recoil while the bullet's still in the barrel. But with a springer, it has to recoil while the projectile is in the barrel, you can't avoid it. And small bore PCPs have effectively no recoil. In my opinion, .22lr doesn't have any recoil, and a small bore PCP doesn't have anywhere near the muzzle energy of a .22, so they can't have perceptible recoil.

Now, listen good, I'm only saiyen this once.

Put the hammer valve in the air reservoir, have it removable, so you can precharge several cylinders and shoot all day erry day.

Spring Piston Rifle

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