Wooden stock marble rifle

[POLAND_SPUD]

hmm well it seems that JSR has a fair point - his idea could improve flow and opening time.. and on top of that you could use a longer barrel


the biggest disadvantage of JSR's design is the fact that there is a lot of force exerted on the piston and thus teh triggering mech has to be very sturdy...
but it seems to be within capabilities of a triggering mech of a springer

[jackssmirkingrevenge]

the biggest disadvantage of JSR's design is the fact that there is a lot of force exerted on the piston and thus teh triggering mech has to be very sturdy...

Not necessarily, you can make the piston only slightly bigger than the diameter of the barrel, the net force on the trigger will be minimal, at least well within what a springer normally has to take.

[Noxious]

Hmm.. 28 mm OD chamber 20 mm OD long barrel inside that = Little chamber volume = boring!

Much air + big caliber + short barrel + pretty fast valve = cool!

And my desing draws chamber towards to original parts so no bolting needed. Trigger mechanism cocks same time when projectile inserted with little extra force. And and..

[POLAND_SPUD]

chamber volume isn't really that important when you use high pressures

besides the volume would be pretty much the same (assuming that the chamber would be as long as the barrel)

but yeah... I see your point...

...though one day you would like to get MOAR power... and increasing barrel length as well as improving the main valve seem like the easiest way to achieve that

[jerome]

wow jackssmirkingrevenge,great drawing and greater idea! has anyone tried this?please add some links,id love to see how this works! also using an old air rifle trigger is brilliant! why didn't i think of that!

[Noxious]

Ok maybe it will work but i think that long thick barrel/chamber thing will be ugly Smaller caliber and metal projectiles should look better in that desing. This is builded under cost of performance for good looks and i wanted it to be that marble caliber. Maybe i should mention that in first post =) (wait.. i did that ) This was also relatively easy design to build.

But good idea still. I just like it that way

Longer barrel is possible.. i did some photosopping. Not too ugly

http://tekniikka.pommi.fi/kuvat/Kaikkee ... toshop.jpg

This morning i builded front sight. Now sights fits to style what i looking for. I post some pics after todays shooting..

[jmadden91]

wow jackssmirkingrevenge,great drawing and greater idea! has anyone tried this?please add some links,id love to see how this works! also using an old air rifle trigger is brilliant! why didn't i think of that!

He did it himself right here 8)

http://www.spudfiles.com/forums/the-bea ... t7457.html

[jerome]

thanks a lot jmadden91!

[Noxious]

That pics what i promised.

http://tekniikka.pommi.fi/kuvat/Kaikkee ... re-013.jpg
http://tekniikka.pommi.fi/kuvat/Kaikkee ... re-014.jpg
http://tekniikka.pommi.fi/kuvat/Kaikkee ... re-015.jpg
http://tekniikka.pommi.fi/kuvat/Kaikkee ... re-016.jpg

Shootings stayed to 5 shots... too cold today

[Noxious]

Hi again,

Weather is getting warmer and i buyed a chronograph so i have some real data:


Marbles, weight ~ 5.5 g

78 m/s @ 5 bar = 17 J
90 m/s @ 8 bar
102 m/s @ 10,5 bar = 28 J

Airsoft BB shotcharge 130 m/s

I did some GGDT simulations and with 26 cm barrel i lose 2,1 J because of valve rod. That's about nothing. At 50 cm barrel i lose 3,5 J that's very little too. Valve seems to be pretty effective?? Well with same diameter valve as barrel bore and 26 cm barrel GGDT giving 33 J and 110 m/s so my lose with that valve desing is 5 joules.

With 50 cm barrel i can rise energy to 42 joules and velocity to 123 m/s says GGDT. I will going to test that in real life.

Some upgrades made too. I shortened inline hose and added valve to it. So after gun is pressurized it can be disconnected and go to shoot that one shot anywhere. Copper is also colorized.

Some pic with couple of my other guns..

http://tekniikka.pommi.fi/kuvat/Kaikkee/lutkuja.jpg

[Noxious]

I did more chrono shots today with longer barrel (50 cm)

GGDT works Even with wrong type valve. Other values i can measure but with flow coef i get it right with first chrono values at different pressures.

Real results are so close.. with 5.5 g marble and 50 cm barrel = 122 - 125 m/s (400 -410 fps) max: 43 J
and i tested 2 g steel BB's too = 158 m/s (518 fps) 25 J

That BB's velocity GGDT gives wrong (170 m/s) so burst disk at valve type is not perfect simulation as this gun With marbles i can simulate where i can improve that gun. Generic valve can be closer with light projectiles if i can measure my valve opening time. Or test values what brings me closest to real results like i did for now.

Sabot and BB:
http://jks2.jynkky.fi/~noxi/BB_shot.jpg

Accuracy was very bad so sabot needs some development

[SpudFarm]

Haven't seen this before, I would just like to congratt you on a great job!

This makes me want to make a pneumatic coaxial in rifle size. Have enough to do on hybrids right now but I want to make something like this sometime

Great job!

[Noxious]

Ou.. i forget new pics...



http://jks2.jynkky.fi/~noxi/kuvat/AR100 ... re-020.jpg

New charging system
http://jks2.jynkky.fi/~noxi/kuvat/AR100 ... re-018.jpg

http://jks2.jynkky.fi/~noxi/kuvat/AR100 ... re-019.jpg

Closeup

http://jks2.jynkky.fi/~noxi/kuvat/AR100 ... re-021.jpg

and thanks SpudFarm!

[LovableAirGuns]

Im loving this gun so much hope you bring out a damage video

[Zeus]

Might I add that this thread is around eight months old and thus I must quote the rules.

Old threads may be kicked up, if you have something relevant and timely to say. Useless ("Cool!") or untimely ("you can find X here" as a reply to a two-month old thread such as "I need to find X by tomorrow") replies may be deleted.

It won't hurt to review the rules, some might flame you for kicking an old thread.