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Most accurate/predictable 6~15mm airgun ammo?

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Unread postAuthor: Labtecpower » Sat Jul 14, 2012 2:34 pm

mm.. beetje ver weg :D
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Unread postAuthor: jackssmirkingrevenge » Sat Jul 14, 2012 6:36 pm

Tsukiten wrote:What matters to me is that the projectile doesn't come to a dead stop (zero horizontal velocity) before reaching 50 meters. If the projectile would impact the target at an 45-degree angle, that really is good enough for me. As long as there's a chance that the numbers produced by equations and there real-world results match up a bit.

This doesn't really make sense.

Let's say you have a series of targets - let's say beer cans :D - at 5, 15, 25, 35, 45 and 50 metres.

You can hit all them with a $3 airsoft pistol, or an M16 assault rifle.

This is a ballistic chart for the round fired by the M16:


At 50 metres it's shooting practically in a straight line, with almost no bullet drop and no time for environmental factors like wind to significantly affect the bullet. At all the distances mentioned above you can aim at exactly the same spot without caring about wind or gravity, and always hit the beer can.

Have a look at some data for airsoft BBs (fromthis epic study! This section in particular.)


To hit the target at 50 metres with the BB gun, you'll be shooting up in the air like you're holding a starting pistol and will need one of these to sight:


You'll also need one of these to know precisely what wind direction and speed was, air temperature, pressure humidity...


You also need a laser rangefinder to know the EXACT distance to the target:


In a nutshell, if you want to avoid all these ancillary items, you want to be firing as fast as possible in order to have as flat a trajectory as possible.

About power: currently I'm trying to measure the spring rate of the spring I have, after which I can calculate what its maximum performance would roughly be like. If that doesn't look very optimistic, I can go pneumatic or try out that crazy idea of mine with rubber bands.

I made this when I was young. First and last springer I ever made.

A pneumatic is a much, much, much better idea ;)

Note that the rubber bands will not directly drive the piston. The rubber bands could for example drive something along 5 times the length of the piston, after which a system of pulleys or gears or whatever transforms the length of displacement into the length of the piston and thus multiplying the excerted force on the piston by 5.

Won't help you I'm afraid, don't forget that pulleys or gears involve energy losses.

But secretly, I'm hoping to prove everyone wrong

You're welcome to try, and I don't mean to sound discouraging, but I'm 100% sure you'll be wasting your time ;)
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