Design an air rifle for the military

[mercury]

check this site out.....

http://shop.pneudart.com/type-p/

maybe one can replace with appropriate toxins.....

http://www.pneudart.com/projectors.php

seems to be a restricted subject...not much info on the net. but weird hints of Israeli special forces using some modified versions of their rubber bullet guns.

[bennedose]

c
http://www.pneudart.com/projectors.php

seems to be a restricted subject...not much info on the net. but weird hints of Israeli special forces using some modified versions of their rubber bullet guns.

There is one rifle there called "dan inject" that has an effective range of 130 meters. That is interesting.

[target shooter]

Yeah good idea . Design one n give to a soldier. AND also provide him a shoebox compressor , hose, 5kv generator, enough fuel and 4 more soldiers to carry all these.
Well mungeri lal was from this country only.
Some suggestion that may come handy during
R & D .
1. Air rifle pellets don't like a velocity beyond 950 fps. And they express their dislike in accuracy.
2. Tank size and maximum fill psi are limited.
3. As the bore / calib increases the shot counts decreases. if you intend to arm a soldier with 90 rounds , he will have to carry 2 scuba tanks or a shoebox and a generator.
A cunning enemy then will not aim the soldier but the bomb he carries. Yes scuba is air bomb.
Now design copy paste from sam yang.

Honestly guys this thread may have negative impact on the legal tangle of air gun and license.
I think the matter is still hanging like a democle sword.


Regards,

[timmy]

If bore friction is an issue and a large one is needed for efficiency, demanding a sabot, I wonder: Might not a sabot be made out of some super-slick material similar to teflon, and perhaps even molded with the rifling engraved somehow? This would even eliminate the energy needed to engrave the sabot. In this way, the projectile could be shaped to the best ballistic shape.

[bennedose]

If bore friction is an issue and a large one is needed for efficiency, demanding a sabot, I wonder: Might not a sabot be made out of some super-slick material similar to teflon, and perhaps even molded with the rifling engraved somehow? This would even eliminate the energy needed to engrave the sabot. In this way, the projectile could be shaped to the best ballistic shape.

Interesting idea. In fact with modern manufacturing techniques and materials this may be less of a problem than the traditional soft lead which was expected to conveniently mould itself to the grooves. And in the absence of hot gases I wonder if the rifling itself would be less prone to damage. Using a suitable sabot a 0.3 inch round (or smaller or bigger) could be shot through a single standard bore of some larger size.

For me there are some unknowns - stuff which I have no idea about. One thing is how much more are lighter projectiles affected by wind? Another issue is something that has been intriguing me. It's like this - let me simply post what I can recall off the top of my head. For example an AK 47 fires rounds at about 700 meters per sec and its effective range is said to be about 400 to 500 meters. That means that the AK 47's round will have a flight time of nearly one second - OK maybe 3/4 second as a guesstimate. Similar things hold true for sniper rifles where he round is actually in the air for a second or more - a huge huuuge length of time, during which it remains accurate AND true AND effective.

Does this mean that if one designed an air powered sniper rifle and had a suitably heavy round, then one could reasonably expect that the effective range would be about 1/2 to 3/4ths of its muzzle velocity? That means that if one could squeeze out say 450 meters per second one could design for accuracy and effective range up to say 200 or 300 meters? I say "heavy round" simply because I believe heavier ones are less affected by wind and retain energy (and velocity in fact) for far longer than lighter rounds.

[timmy]

I only have a short time to write tonight, but at a very basic level, things that causes a bullet to be affected by wind are the bullet's ballistic coefficient and the bullets velocity. The higher these figures are, the less affected by wind the projectile will be.

Velocity is somewhat straightforward.

Ballistic coefficient is the measure of how the bullet is affected by drag. The more quickly a bullet slows down over a distance, the more it will also be affected by crosswinds. One thing that affects the ballistic coefficient is the bullet shape. A round ball has a horrible ballistic coefficient, slows quickly, and is greatly affected by crosswind. A round nose bullet is better. A spire point or spritzer bullet is better yet, and a boat tail bullet is even better still.

Another thing that affects ballistic coefficient is sectional density. Sectional density is the ratio of the bullet's weight (actually, its mass) to the bore area. A long skinny bullet has better sectional density and thus, a better ballistic coefficient than a short, fat one.

The shape and ballistic coefficient can also affect penetration of the target, but that's a whole 'nother subject.

[bennedose]

For the time being I am going to set aside the question of what shape and type the projectile ought to take - except that it should be 0. 3 inch (7.62 mm) and weigh about 20 grams.

Some more rough calculations show that a cylinder of air with a volume of 5 liters should be just about the size of a shoebox. At 3000 psi this tank will hold 1000 liters of air. If 10 liters are used per shot and the minimum working pressure has to be above 1500 psi then at least 50 shots can be fired with one shoebox sized tank filled with 3000 psi air.

[bennedose]

For the time being I am going to set aside the question of what shape and type the projectile ought to take - except that it should be 0. 3 inch (7.62 mm) and weigh about 20 grams.

Some more rough calculations show that a cylinder of air with a volume of 5 liters should be just about the size of a shoebox. At 3000 psi this tank will hold 1000 liters of air. If 10 liters are used per shot and the minimum working pressure has to be above 1500 psi then at least 50 shots can be fired with one shoebox sized tank filled with 3000 psi air.

Hmm here's a 303 air rifle with a 50 grain - 3.2 gram pellet 100 plus yard range. 250 bar pressure (3600 psi)

[youtube][/youtube]

[brihacharan]

Hi Bennedose,
Hmm... The Wolverine 303 air rifle with a 50 grain - 3.2 gram pellet 100 plus yard range. 250 bar pressure (3600 psi)

A well documented video - enjoyed watching it...
In my considered opinion it may not suit the military ... Carrying a scuba tank etc... & God forbid if the valves start giving trouble during field action /combat / assault etc.....
Nevertheless a very impressive AR, aesthetically designed, functional & accurate...
Briha

[kshitij]

Happened to go through this old thread.

@bennedose, any progress with the designs?
you might find these interesting:
http://www.extremebigboreairrifles.com/
http://www.extremebigboreairrifles.com/product.html
http://mrhollowpoint.com/

not sure about the military applications, but it sure would be fun smashing watermelons with a 300gr .50cal hollow point pellet