How movie guns work

[Mighty Mouse]

A question arose in my head today about how semi-automatic and automatic guns in the movies work, in particular where you can see expent shell casings. In order for them to be using blanks, they have to have the BFA (blank firing attatchment) to cycle the gas backwards to the bolt, and you never see those in the movies. If it's not blanks they are shooting what could it be? I don't think they would be firing real rounds on a movie set but that is all I can think of that makes sense. :???:

[Luckyorwhat]

Weld a plug in the barrel, leave enough open to keep pressure high enough for cycling but low enough to avoid KB.

[Bearbait 37]

Use Caliber particular blanks and spray WD40 down the front barrel ( extremly short spray) wear gloves and eye protection have buddy standing next to you with fire extinguisher

[firemachine69]

CGI



Very, very few recent movies use actual live (or converted) FA firearms... Just too much liability...

[ancorp]

Im pretty sure real firearms are mostly used still. All fire blanks, blowback operated dont need a BFA, gas operated either have the BFA and overlayed effects, or (if available) use blanks with plastic bullets that burn up in the air almost instantly, travel just enough to allow the gun to cycle properly (such as 5.45x39 blanks). Im sure a a BFA with a small hole on it to allow the flame to escape, combined with a lighter bolt/recoil spring may allow enough pressure for cycling...

Edit: here are the blanks with the plastic bullets I speak of:
http://www.sportsmansguide.com/cb/cb.asp?a=158925
Very reasonable prices IMO!

Cheers!
Alex

[shagmaster]

In some movies there is a special BFA that can be 'hidden' in the barrel of the gun, only visible when looking straight down it. These are different to the normal HUGE BFAs that go over the flashhider when blanks are used for military training. I realized this while watching 'Clear and Present Danger' when the soldiers are in the jungle and one points his rifle more or less right at the camera and the BFA is visible inside.

[Luckyorwhat]

Ancorp, I know there's lots of safety nazis here saying things like, "don't transport your airsoft gun unless it's disassembled into at least 3 pieces in a a locked container and you hide the key in your rectum".

But those 'blanks' are, imo, a serious safety hazard. Brandon Lee and Jon Hexum prove the point (though Jon Hexum shows idiots should not touch firearms).

4 rules:
1)every firearm is loaded
2)keep your finger off the trigger until you want to fire
3)don't point the gun at anything you don't want to destroy
4)beware of your target and what's behind it


There is NO safe way to point a firearm at another person. Especially if you have a magazine in the chamber, loaded with cartridges.

For the record they also make/made wooden bullets, the Germans used them with training in WW2.



(or if you like, the Canadian safety rules:
Assume the firearm is loaded
Control muzzle direction at all times
Trigger finger must be kept off trigger and outside trigger guard
See the firearm is unloaded, prove it's safe

Point the firearm in the safest available direction
Remove all cartridges
Observe the chamber is empty
Verify the feedpath is empty
Examine the bore

Cooper's 4 rules are more simple and robust, while the Canadian ones are technical and bureaucratic, but they all work excellently. Unlike those blank cartridges!!!

[Gryphon]

Geez. Lots of misinformation here.

Use Caliber particular blanks and spray WD40 down the front barrel ( extremly short spray) wear gloves and eye protection have buddy standing next to you with fire extinguisher

Um, no.

All fire blanks, blowback operated dont need a BFA....use blanks with plastic bullets that burn up in the air almost instantly

Um, no.

In some movies there is a special BFA that can be 'hidden' in the barrel of the gun, only visible when looking straight down it. These are different to the normal HUGE BFAs that go over the flashhider when blanks are used for military training. I realized this while watching 'Clear and Present Danger' when the soldiers are in the jungle and one points his rifle more or less right at the camera and the BFA is visible inside.

Correct. Most movie guns are plugged this way.

Guns that actually do fire blanks have to have the barrel plugged unless they're manually operated firearms. A blowback automatic weapon will not cycle if there is no inertia from moving a bullet since it is that which provides the force necessary to blow back the bolt (remember Newton's 3rd Law?). A gas operated firearm needs a barrel plug in front of the gas tap to create enough back pressure to cycle the bolt. Revolvers, bolt actions, pump actions, and lever actions don't need barrel plugs to function with blanks.

A blank load is a standard brass cartridge case sans bullet, typically rose crimped to resemble the bullet it would normally be loaded with so that it will feed properly in a magazine. This sometimes necessitates using brass other than the chambered caliber so the neck of the casing can be crimped into a bullet shape. Provided the head is the same diameter and thickness you can trim the length as needed and fire form the shoulder as required.

The powder used is a special blend formulated especially for firing blanks and is extremely quick burning. Using it to reload any commercial cartridge with a bullet would be disasterous. This, coupled with the specialty of manufacturing blanks in some esoteric calibers for oddball guns you might find in a war movie for instance, results in them costing a good $1.00 to $3.00 a piece. In Saving Private Ryan the beach sequence apparently used something like $100,000 worth of blank cartridges.

CGI

Very, very few recent movies use actual live (or converted) FA firearms... Just too much liability...

Also correct. Anyone find it interesting how Stargate SG1 always gets the latest and greatest firearms that just so happen to coincide with Tokyo Marui's release dates? Their current weapon of choice I'm told is the MP7. You can bet they're not using real ones.

[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

[Mighty Mouse]

Thanks for the info.

[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.)

Point in case, in scenes were people are getting shot point blank (suicides, execution -style shot to the back of the head, etc) you can't use a blank firing gun. So they use these so-called blank-firing non-guns, which actually have a mag (and special blank rounds similar to the 22LR blanks they use in nailguns), moving slide, etc. however the barrel doesn't have a bore by design (except for the muzzle, for looks). The entire contraption is designed to vent the gas upwards through the ejection port (if you look for it you can sometimes catch it, specially in older movies or when there's no budget for CG cleanup of a detail like that).

Combined with a squib and the right camera angle, you get a functional looking pistol (or whatever gun), cycling action, a flash of unidentifyable flying brass and blood and brain matter splashed against the wall. Yay!

[ancorp]

Yep, theres also another way for point blank shots, not firing anything at all like when Samuel Jackson gets shot in the back of the head with a silenced 1911 in Goodfellas, all that happens is the hammer drops... bah!

Cheers,
Alex

[ancorp]

Originally Posted by Gryphon

...A blowback automatic weapon will not cycle if there is no inertia from moving a bullet since it is that which provides the force necessary to blow back the bolt (remember Newton's 3rd Law?)....

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.

Cheers,
Alex

[walks]

the use of "blank fireing disk" is the most common way to turn a real gun into a movie gun, with AR and AK rifles you simply take off the flash suppressor/muzzlenut/brake and put in the disk then put the disc back on the gun, for instance a few years ago I was attacking a platoon position at night and when the C-6 started barking it was amazing, what they had done is they got a dime drilled a hole the same size as the one in the BFA and dropped it in talk about FLASH.....same thing applies to movie guns only different blank companies have different charges in their stuff so finding the right disk for the right blank is important (dont want to blow the thing up in your face now do you)

[Jake]

Originally Posted by Mighty Mouse

A question arose in my head today about how semi-automatic and automatic guns in the movies work, in particular where you can see expent shell casings. In order for them to be using blanks, they have to have the BFA (blank firing attatchment) to cycle the gas backwards to the bolt, and you never see those in the movies. If it's not blanks they are shooting what could it be? I don't think they would be firing real rounds on a movie set but that is all I can think of that makes sense. :???:

Here's a page that goes into some detail about movie guns if you're interested:
http://www.moviegunservices.com/mgs_weapontypes.htm