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14mm Automatic Air Rifle

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: jackssmirkingrevenge » Sun Sep 27, 2009 1:41 am

Your link should have looked like this:

(url=http://members.shaw.ca/cronhelm/SubsonicBullet.html)backwards!(/url)

replacing the round brackets with square ones.

It would be interesting to see how effective rifling is in this case.
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Unread postAuthor: al-xg » Sun Sep 27, 2009 4:26 am

I'd have throught they require more stabilisation flying forward than backwards, or is that what you meant ?
I've come accros this site before :)
Tear drop shaped bullets (point backwards) could also be interessting.

I did try that aluminium bullet, erm but like for 2 shots and from quite close up (I didn't want to lose it in case I needed it again for another mold) and it did hit the target point forward, but it could just be luck at that range.

The diabolo pellets I made worked really well, but then they would as they're pretty much stable out of a smooth bore. (I have a few pics of that somewhere Ill try uploading)
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Unread postAuthor: Pookydarts » Sun Sep 27, 2009 11:19 pm

Thanks JSR, i'll get it eventually!...:roll: :lol:

Ummm, as far as flying forwards/backwards,
Yes, I was trying to say, flat bit towards target (heavy end towards target) should be easier to stabilise than pointy bit towards target.

Like trying to throw a javelin with the heavy bit at the back, doesn't make sense really! :P
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Unread postAuthor: jackssmirkingrevenge » Sun Sep 27, 2009 11:43 pm

Pookydarts wrote:Ummm, as far as flying forwards/backwards,
Yes, I was trying to say, flat bit towards target (heavy end towards target) should be easier to stabilise than pointy bit towards target.


Not only that, you can take out a tank too:D

Military users of reversed bullets were Germans during the 1st World War! Soon after the arrival of British tanks in Cambrai, France, 15th September 1916, they were found an Armor Piercing projectiles available for each rifleman in the trenches. (The real AP bullets were issued to the snipers only). Quotation from the booklet "KNOW YOUR ANTITANK RIFLES" by E.J. Hoffschmidt, published by Blacksmith Corporation:

"Like most secret weapons, the tank had its bugs. They were mechanically unreliable and several were soon captured by the Germans. After some hurried testing, they found that by simply reversing the direction of the standard infantry rifle bullet in the cartridge case, it would penetrate thru the British tank armor".

This German "standard infantry rifle bullet" was a flat-based, pointed FMJ projectile for 8 x 57 mm Mauser rifles and machine guns with mild steel (I prefer the term "iron") jacket, weighing ten grams/ 154 grains. Nominal muzzle velocity of it was ca. 2920 feet per second (890 m/s), but when reversed, it might be 900+ meters per second, because the powder charge was not reduced. Nominal maximum chamber pressure was 3100 atmospheres, but because of the compressed powder charge, it was presumably about 4000 atm, when those improvized "anti-tank loads" with reversed bullets (seated almost the base flush with case mouth) were shot. Fortunately to Germans, action of Mauser Model 1898 kurz rifle is able to stand occasionally 5000 atmospheres of chamber pressure if the cartridge case is able to seal it without split of it's head.

It was rather a rule than an exception that the rifle bolt was stuck tightly. It was needed to beat open with a boot sole or fire-wood. Germans cursed the actions of Mauser rifles when they fed the blunt-pointed cartridges into chamber (essentially from the magazine), but they blessed the sturdy and broad extractors which enabled removal of stuck case without extractor-hook breakages or case rim broke-offs.

Use of reversed bullet to perforate 8.2 mm thick armor plate of earliest tanks was based on an elementary fact: You need considerably less energy to punch/ "die cut" the hole through a plate than to puncture it with a pointed drift, especially that of rather soft material like German Spitzer bullet, which must make a hole with diameter 17 to 20 mm through armor plate when struck point-on, demanding 1000+ m/s STRIKING velocity, but mere 8.5 to 9.0 mm when struck base-on and therefore acted as a wadcutter. Plates were of face-hardened mild steel, riveted on the angle iron skeleton frame. There were 2 - 3 millimeters wide slits between the plates, and each rivet was an "Achillean heel" of the first tanks. British tankers learned very soon to wear wire-mesh "tanker's mask" with goggles, when some colleagues of them were lost their eyesight by the spray of molten lead droplets and fragments of hot iron.
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Unread postAuthor: Pookydarts » Sun Sep 27, 2009 11:56 pm

If only I had some old tanks laying around to help with load development... :(
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Unread postAuthor: POLAND_SPUD » Mon Sep 28, 2009 12:24 am

@JSR
you don't need flat nosed ammo to do that... clicky
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Unread postAuthor: jackssmirkingrevenge » Mon Sep 28, 2009 12:55 am

POLAND_SPUD wrote:clicky


Ah, but reversed bullets were tried in the First World War, the first time that tanks had been encountered on the battlefield. The Germans eventually developed the "K Bullet" specifically made for this purpose and removing the need for improvisation. They also made the Maroszek's grandfather, the Mauser M1918 that relied on a bigger calibre as opposed to a small fast bullet.
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Unread postAuthor: poppamies » Fri Oct 16, 2009 4:39 am

just thinking where did you buy the qev?
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Unread postAuthor: al-xg » Fri Oct 16, 2009 8:11 am

Its an English QEV, bought it off CT from the UKSGC before he started up the shop.
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Unread postAuthor: POLAND_SPUD » Fri Oct 16, 2009 2:23 pm

I know they are not english though they became popular there.... AFAIK they are produced by camozzi in Italy (and probably several other companies)
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Unread postAuthor: poppamies » Fri Oct 16, 2009 3:02 pm

buuyaa! it arent mamerican! im from finland so i dont have to pay customs if i buy it from uk

what is the outer diameter of the air reservoir?

how many shots can you fire with one fill?
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Unread postAuthor: POLAND_SPUD » Fri Oct 16, 2009 3:45 pm

I can buy them in Poland... probably there are some shops selling pneumatic stuff in Finland that have them
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Unread postAuthor: poppamies » Thu Oct 22, 2009 3:07 pm

what is the outer diameter of the air reservoir?
how many shots can you get from one fill?
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Unread postAuthor: Asian~creation96 » Tue Jan 10, 2012 11:17 pm

how is your QEV piloted?
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Unread postAuthor: Crna Legija » Wed Jan 11, 2012 1:13 am

Asian~creation96 wrote:how is your QEV piloted?


looks like a solenoid valve.
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