Blanks fired in pistols

July 8, 2009 8:55 AM

Do blanks provide enough backward motion on the casing when fired to cycle the action of an automatic pistol?

Thinking in particular of two different German military pistols, P-08 Luger which has a knuckle action, and P-38 which has a slide action similar to modern pistolas.

posted by ackptui to sports, hobbies, & recreation (12 comments total)

No, they don't. Movie props designed to use blanks have to have barrel constrictors installed in order to make enough chamber gas pressure to make the autoloader work properly.
posted by Chocolate Pickle at 8:57 AM on July 8 [1 favorite]

Generally, to fire blanks from a rifle, you need to attach a Blank Firing Attachment, which closes the gas circuit that pushes the bolt back to load the next round.

Both pistols you mention use 'short recoil' actions. Blanks provide little to no recoil as there is nothing being pushed against by the gases escaping from the cartridge. Most blank-firing pistols are normal pistols with a closed barrel swapped in, or specially made blank-firers with permanently closed barrels.

So, you could fire one round from either of these, but it wouldn't cycle the action.
posted by Happy Dave at 9:01 AM on July 8

Dave, they don't want the barrel closed off completely, because barrel flashes look cool on film.
posted by Chocolate Pickle at 9:02 AM on July 8

Well, yeah, of course. Teeny tiny holes for the muzzle flash, but it's effectively a really constricted space so the gases mostly push on the gas parts.

Makes your weapon incredibly dirty, in my experience.
posted by Happy Dave at 9:04 AM on July 8

Generally no. Depending on the action of the gun in question, you have to make some modifications to get the action to cycle.

If the gun is gas operated, you use a "blank firing adapter" that basically plugs the barrel somewhat, in order to generate sufficient gas pressure. The most common one I've seen like this is for the M-16; it's used by the military and actually screws right to the muzzle.

For blowback/recoil operated guns, it's a somewhat more complex operation. This thread discusses some techniques. Some are reversible, like replacing the recoil spring with a lighter one, others aren't, e.g. "shaving" the locking lugs, plugging the barrel, or boring a bleed port for the gas.

The issue is that blanks generate gas, but since they don't actually propel anything out of the gun, there's not much recoil force to work with.
posted by Kadin2048 at 9:10 AM on July 8

The obvious next question is, "What happens if you try to fire a live round with a barrel constrictor in place?"

It depends on the specific case, of course, but usually the barrel constrictor gets blown out and then the gun fires normally. That was certainly the case in France last year. The soldier in question ran through an entire magazine of live ammo before he noticed all the people bleeding.
posted by Chocolate Pickle at 10:06 AM on July 8

What is the mechanism where blanks kill people? I know Brandon Lee was killed by a hung bullet, is that how it always happens?
posted by Mitheral at 1:03 PM on July 8

What is the mechanism where blanks kill people? I know Brandon Lee was killed by a hung bullet, is that how it always happens?

The gases produced by the blank are hundreds to thousands of degrees hot, and going very fast. They can do significant damage on their own.

Likewise, some blanks (particularly in revolver cartridges) have a small bit of wadding in them. Even a quarter-inch square of cotton can hurt if it's going fast and right next to your head.

Pieces can break off the blank casing as it's fired. Small but, again, fast.

The blank firing device (barrel constrictor or adapter) can become dislodged.

And as you mentioned, there can be some other random bit of debris.
posted by Netzapper at 1:56 PM on July 8

Jon-Erik Hexum was joking around between takes, and put a pistol loaded with blanks up to his temple and pulled the trigger. He fell down, dead.

What happened was that the shockwave from the blank broke a piece of his skull loose and drove it through his brain. It might as well have been loaded, for all the difference it made.

If he'd had the pistol 3 inches away from his head, it probably wouldn't have hurt him.
posted by Chocolate Pickle at 2:19 PM on July 8 [1 favorite]

Supposedly, the Brandon Lee death was caused by a chain of events. They wanted a close-up of the gun firing, but because it was a revolver, you could easily see the bullets were blanks. So for the close-up, they filmed the gun with bullets where the wadding had been removed, so the actor could pull the trigger, the rounds would cycle, but the bullets wouldn't fire. From what I understand, the firing cap on the back of the shell was actually strong enough to dislodge the bullet, forcing it into, but not out of the barrel. They switched over to the blanks, and someone forgot to check the barrel. The shockwave from the blank was strong enough to launch the bullet, just as if it had been fired normally.
posted by Ghidorah at 4:11 PM on July 8

Chocolate Pickle: "Jon-Erik Hexum was joking around between takes, and put a pistol loaded with blanks up to his temple and pulled the trigger. He fell down, dead."

I want to thank you for this post, because it led me to the page on Cover Up, which is, of course, the answer to a question that's been plaguing my memory for years : What is the name of the series that had Bonnie Tyler's Holding Out For A Hero as the title music? Finally!
posted by benzo8 at 3:21 AM on July 9

If you want to practice by dry-firing, what you want to buy are some snap caps (or a different brand). You'll have to cycle the action manually after each dry-fire, but it lets you do it pretty much to your heart's content without worrying about damaging the firing group parts.

I have a set of 4 or 5 for every cartridge that I own a gun in, and when I get a new gun I'll generally sit around for a while with a snap cap in the chamber and do some dry firing to get a feel for the trigger. Saves a lot of time and ammo on the range.

I have the nice bright orange ones, just because they're more visible in the action.
posted by Kadin2048 at 7:01 PM on August 4