Archive for April, 2015

Looking Through The Keyhole

Monday, April 27th, 2015

Yet more reader questions are answered.  This time around, it concerns yet again my past post on derringers.

I heard that derringers will usually keyhole.  Is that bad?”

Is keyholing bad?  Yeah, pretty much.  But to understand why we must first discuss what is meant by keyholing.

The way to make bullets stable in flight is to give them a spin.  If they are revolving around their long axis while flying downrange, they will be much more accurate.

bullet spin

This spin is imparted to the bullet by the rifling cut inside of the barrel.  But what happens if the barrel is so short that the bullet pops out before it has time to start to spin around the long axis?  If that happens, the bullet most usually starts to tumble around any old way.

tumbling bullet trajectory

This significantly reduces the range and accuracy of the shot.  The bullet tends to drift around wherever it likes, wandering about like a dog sniffing trees.  Not only that, but it also tends to strike the target in some way other than nose first.

KeyHole-Tear-1

KeyHole-Tear-2

(Picture source.)

Those might not look much like keyhole, but the name comes from the wounds that are made by such tumbling bullets.

keyhol bullet wound in skull

old keyhole

Not a perfect match, it is true, but descriptive nonetheless.

So tumbling bullets can produce oddly shaped wounds, and those wounds resembled a keyhole shape.  Why are all tumbling bullets referred to as keyholing, since all of them do not produce such shapes when they strike the target?  Pretty much because people think it sounds cool.  (“My gun is keyholing!“)

Getting back to derringers, their short barrels increase the chance that the bullet will not pick up enough spin before it leaves the barrel.  This doesn’t mean that every shot from a derringer will keyhole, but it does seem to be a fairly prevalent situation.

engraved derringer

Okay, so bullets that tumble are not as accurate, nor do they have as great a range, as bullets that behave themselves and spin in the proper manner.  This problem is relatively common with derringers.

But is it really a problem?  Derringers are not known for their long range accuracy, and are intended to be used against violent criminals that are right on top of the defender.

angry man pointing finger

Who cares if the bullets tumble?  They will still hit as hard, won’t they?

Tumbling bullets do tend to slow down much faster than those which spin due to air resistance, and derringers are intended to be used against targets that are close enough that this wouldn’t be much of a factor.  But keep in kind that tumbling bullets also tend to strike the target at an odd angle.  This means any defensive ammunition used, such as hollow points, won’t work as advertised.  They have to hit nose first in order to expand.

expanded hollowpoint bullets

Obviously, this isn’t going to happen if the bullet strikes the criminal any old way.

If one favors boring old ball ammunition, then one should be pretty confident that their derringer will work about as well whether or not the bullets tumble.  But if one pays for defensive ammo, then bullets which tumble can mean that the extra cash was wasted.

It Isn’t Really A Jet Of Flame

Saturday, April 18th, 2015

Time to answer some reader mail.

I enjoyed your post on derringer’s, but had heard that shorter barrels increased barrel flame.  Is this going to be a problem if they are shot indoors?

Do guns emit vast jets of flame when fired?  Certainly seems so if you go to the movies!

james bond muzzle flash

val kilmer in heat

expendables 2 muzzle flash

(Picture source.)

My goodness!  It is a wonder that they don’t catch the entire neighborhood on fire!

Muzzle flash is exciting in the movies, which rely on visual cues to indicate drama and conflict.  Many times the flash is added in post production as a computer image laid on the film.  Average guns loaded with normal ammunition don’t look like that under normal lighting conditions.

Okay smart guy, so what does it look like?

Machine gun

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Derringers – Not A Fan

Monday, April 6th, 2015

Henry Deringer was an American gunsmith who came up with a pocket pistol for self defense in 1825.  It was an amazing collection of innovations, a clear example of a flash of brilliance.

flintlock derringer

I know what you, modern reader, is thinking.  “Yeah, so it is a derringer.  So what?

Mr. Deringer’s sole act of brilliance was to take an extremely short barrel chambered for a large bore, man-killing bullet and mate it with teensy tiny furniture.  This created a gun which might be doll sized, but which still packed a devastating punch.

The time for the idea had clearly come, as the public bought these guns as fast as Henry could churn them out.  This brought Mr. Deringer considerable economic success, but counterfeit versions of his gun started to be produced at an amazing pace.  Henry sued some of the gunsmiths who would build copycat versions of his invention right down to his proof marks, arguing that they were just cashing in on his fame.  He won enough court cases that the copycats started to call their works “derringers”, with an extra R.  Since the copies outnumbered the authentic by several orders of magnitude, and so made a much greater impact on the public, we now refer to Henry’s invention by the mangled version of his name.

But don’t cry for Henry.  As I mentioned before, he made out pretty good and died with cash in his pockets.

This basic idea of tiny guns made for ultra-concealment has proven to be amazingly durable, and the basic design has been constantly upgraded.  It only took a few years before Henry dropped the original flintlock mechanism for a percussion cap ignition system, placing derringers at the cutting edge of firearm technology at the time.

percussion cap derringer

The demand for such guns has continued into the present day, with double-barreled versions chambered for the .38 Special cartridge being particularly popular.

38 caliber derringer

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