How movie guns work

[Gryphon]

Originally Posted by ancorp

Woops! Yes, you are absolutely right.

As for the blanks with plastic bullets. Yes they are more dangerous than standard crimped blanks, but for military training, I think they are the optimal solution. Proper cycling, and a nice big flame... its all there with much less recoil and no bullet holes I doubt they are used in movies much, if at all, but they are the only way that I can think of to have a live automatic firearm operate properly with blanks with no modifications.

Oh, plastic training rounds! Yes, those DO exist you're certainly correct about that. However I would fire any armorer that would see them used in a theatrical production!

[PTE. Pyle]

Originally Posted by Drake

I'd also add that there's something called "Blank-fire Non-Guns" which are built-as-prop "guns". As someone above mentioned, blank-firing guns aren't "safe", and that not only because of the examples cited; a blank generates enough power to cycle the gun, and while no projectile is launched there's still a very powerful muzzle blast. (There was an incident (and probably others) were an actor from a TV show was messing around with a blank-firing gun and shot himself in the head with it as a "joke"; the muzzle blast caused brain death.)

That was the actor from the movie the crow if im not mistaken.

[yanhchan]

http://www.redwolfairsoft.com/redwol...egory?menu1=16

Fancy lookin...

[Penguin]

I believe the machine guns in Saving Private Ryan were propane powered, it just vented a small bit of propane and then ignited it.

It was much cheaper than using blanks.

[Barf]

Originally Posted by PTE. Pyle

That was the actor from the movie the crow if im not mistaken.

Actually that was John Eric Hexum. He was playing Russian Roulette with a snub nose revolver when he "got lucky". The wad from the cartridge and a piece of his skull was sent into his brain. That is why movies use wadless cartidges now. But the guns are still not safe for point blank firing. With the absence of the wad, more than one actor has gotten powder burns from being shot at close range.

[Gryphon]

Originally Posted by Penguin

I believe the machine guns in Saving Private Ryan were propane powered, it just vented a small bit of propane and then ignited it.

It was much cheaper than using blanks.

How do you propose shoulder fired weapons were powered by propane? I didn't see any propane/oxygen hoses and tanks strapped to Tom Hanks and his boys.

[Penguin]

Originally Posted by Gryphon

How do you propose shoulder fired weapons were powered by propane? I didn't see any propane/oxygen hoses and tanks strapped to Tom Hanks and his boys.

Machine gunes man, machine guns.

Im talking the mounted ones. Not sub machine guns or, rifles.

[Mighty Mouse]

Feeding an MG that fires like 1200rpm (MG42) I imagine would put you in a tight spot so propane seems like a smart idea.

[Luckyorwhat]

Originally Posted by Barf

Actually that was John Eric Hexum. He was playing Russian Roulette with a snub nose revolver when he "got lucky". The wad from the cartridge and a piece of his skull was sent into his brain. That is why movies use wadless cartidges now. But the guns are still not safe for point blank firing. With the absence of the wad, more than one actor has gotten powder burns from being shot at close range.

Hexum, being and enlightened Liberal, was ignorant of guns and happy that way. During a delay on set he jokingly put the gun to his head and pulled the trigger, blowing a chunk of skull the size of a quarter into his brain.

Lee was killed because the armourer had been sent home as un-necessary that night. A revolver that had been used earlier had cartridges with bullets but no powder so that the bullets could be seen for the camera. Either A)a cartridge had a live primer and when the trigger was pulled that was enough to propel the bullet part-way into the barrel, a squib. Or B) a bullet came loose from a cartridge and just got pushed into the barrel. Later when the same gun was used with blanks the bullet was propelled out of the barrel.

IF proper gun safety rules were followed, either negligent discharge couldn't have happened. Even if you break a rule, the rest will cover your ass. It's damned negligent that firearm handling isn't taught mandatory in schools.

[Deftonius]

Originally Posted by SolidifiedPenguin

Yah, stargate started out using MP5s, then when TM released the P90, the used P90s, now the MP7 is released, guess what theyre using

A hero cookie goes to you if you can guess who supplies them with their guns.

[MadMax]

Propane doesn't provide a flare of the right properties. Powder makes sharp short flares with burning particles. Rich propane flares (low oxygen) make the typical bright orange lazy flare. Balenced or lean propane flares (premixed oxygen) are blue or even purple.

Automaticly loaded rifles are typically gas operated. At some point late in a bullet's flight down a barrel, the bullet passes a side tap in the barrel. In Armalites the side tap is about 2/3 of the way down where the triangle sight begins. As the bullet passes the side tap, some gas from propellant combustion (30+kpsi!!!) shunts upwards into the gas tube (in armalites) or directly acts on a cocking rod (e.g. FAL or AK47) which pushes on the top of the bolt to power the recoil cycle.

Blanks do not properly cycle a gas operated automatic firearm because there is no obstruction in the barrel to generate a high enough pressure to work a rifle action. Gryphon is correct in applying Newton's 3rd law of balenced forces. However, I am not sure if Gryph is asserting that the reaction force of the bullet directly actuates the recoil mechanisms. Applying force to the bullet has no effect on the recoil mechanism until the bullet passes the side tap. Before this stage, the bolt in an auto rifle is locked against the breech by the bolt carrier or some similar arrangement.

The accelleration of the bullet exerts a reaction against the propelling gas which results in a high breech/barrel pressure. With no bullet, only light gas and air is accellerated so a low pressure develops which is insufficient to cycle the loading mechanism.

A BFA partially obstructs the barrel to generate a higher pressure to actuate various mechanisms in a rifle. A funny loading results though. Because the BFA is mounted to the flashhider or welded into the barrel, a net tension results which pulls on the barrel when the gun is fired. This does not occur with a bullet except for the frictional force in smushing a bullet down the rifling.

[Penguin]

[MadMax]

Pretty cool Peng. I've heard of propane firing guns, but never seen one firing. Perhaps most movie goers wouldn't notice the difference between a powder flare and a propane one. I just can't see a propane flare looking quite right without particles. Perhaps they're comp'd in in post.

[Penguin]

Originally Posted by MadMax

Pretty cool Peng. I've heard of propane firing guns, but never seen one firing. Perhaps most movie goers wouldn't notice the difference between a powder flare and a propane one. I just can't see a propane flare looking quite right without particles. Perhaps they're comp'd in in post.

heres a generic propane gun firing



I wouldn't mind one, it's another toy for the shelf hehe.

[MadMax]

looks fun, but the colour certainly looks funny.

You should have seen the flare from my potato cannon. 6' angry purple flare which flashed out. Hmm... Maybe it was bright blue and it leaves a purple blotch in your overexposed retina. Hard to say.

Does that gun cycle the bolt?