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Lethal low pressure launcher


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Old 03-19-2016, 11:54 AM   #1
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Default Lethal low pressure launcher

Air guns and air powered launchers are quite topical at the moment. There seems to be quite a few air rifle enthusiasts on the forum. With Jorge getting great results using high pressure air to power his arrow launcher I thought it would be challenging and fun to build something using relatively low pressure air. I will be restricted to sub 150 psi courtesy of my bicycle pump.
As a teenager I worked shifts in a pvc pipe factory. With access to all manner of pipes and fittings, not to mention unrestricted high pressure air, you could imagine the mischief that took place.
Last weekend I glued together a very basic pressure vessel out of 25mm pvc pipe around 500mm long. A ball valve and a tyre valve completed the job. The barrel is a 15mm pipe 1 meter long attaching via a reducing fitting. Roughed out a ply lever to work the valve and I had a working test rig.
This rig is basically a blow pipe on steroids. All my testing was done with 80 psi. Ammo was to be cheap nails with a tape cone stuck on. From the first shot the nails would bend on impact every time. I switched to 75mm and 100mm hardened concrete nails to solve the issue. Testing was done indoors at around 5 to 6 meters range. No problem penertrating 12mm ply, and speed was impressive. Next tested were 150mm nails weighing nearly 30 grams. They hit hard, too hard actually. The unbraced ply was being flung around upon impact, bending the nails as they flew off. Some 19mm pine was clamped in the vice and easily pierced from 3 meters. The final shot was a full power test with the 100mm nail into the clamped pine. Went in and bent !!!!!! the hardened nail.
Will test other ammo options then start on a build.
Envisage a breach loader fully enclosed with a quick opening valve and trigger.


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Old 03-19-2016, 01:10 PM   #2
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I will probably never get into this type of building myself but you, Jörg and BoyTonStu sure keep me entertained with the fun and excellent science of these things.


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Old 03-19-2016, 04:54 PM   #3
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I have a large divers bottle for a pcp rifle.
These threads could corrupt my innocent little mind soooo easily!
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Old 03-20-2016, 01:41 AM   #4
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Holy cow! Im interested in seeing the chrony results. Do you plan on shooting some steelballs out if it?
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Old 03-20-2016, 05:56 AM   #5
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Tried some different projectiles today shooting what I had lying around in the work shop.
Marbles work with wadding and achieve very serious velocities.
Paint balls are a perfect fit for this bore size. Using max pressure ( 140-150 psi) move with insane speed.
Who would have thought that with a bit of cloth tape you could turn 1/2 lead balls into giant air gun pellets. Worked like a charm with decent speed at 80 psi.
Field points work fine but tend to bounce of hard surfaces.
The Bodkin point projectile was plain scary. Was a bit concerned about 25 grams of steel richocheting indoors. No concerns, flew perfectly and hit damn hard even at 80 psi.
I don't think I will have any problems getting this launcher into the lethal category.
Have a few construction ideas and will post future progress.
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Old 03-21-2016, 02:17 PM   #6
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very cool ! ... another projectile I like, easy to do and cheap are steel rods, I cut them from threaded bars ... nastier
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Old 04-03-2016, 11:28 AM   #7
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Put together a working test rig after trying a couple of different configurations. Very crude and absolutely rough workmanship.
Hot glued and screwed ply and pvc. Trigger is basic rolling nut turning ball valve powered by 25-30 pounds of TBS tube.
Trigger works great, very quick action and opens valve completely. A few safe low pressure test shots with paint balls at 60 psi were going to fast to see. Must be getting 350 fps plus easily.
Shooting the duct tape darts showed just how well the trigger worked. At any pressure over 40 psi the tape cones would crumble from the shock of the of air release. The heavy Bodkin dart worked fine up to 60 psi when the breach would blow off even with reinforcing tape.
Will continue to tinker with test rig and projectiles and try to get some chrony results.
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Old 04-03-2016, 12:17 PM   #8
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Awesome but we need videos man.
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Old 04-08-2016, 11:17 AM   #9
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Had time and enough light to launch a few paint balls over the chrony this afternoon.
The results were startling and more than a little scary.
Starting with 60 psi easily cracked 440 fps.
80 psi got me to over 500 fps.
Going to 100 psi gave me over 550 fps !!!
The paint balls were going fast enough to penertrate a exercise mat set up as a splatter shield.
With a weight of around 3.5 grams these paint balls are hitting with nearly 50 joules of energy.
Am really astounded at the performance achieved with very modest air pressure so far.
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Old 04-08-2016, 12:40 PM   #10
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Crazy!!!! Please find some more time! And hit the record button on the cam accidently!


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