Blowguns - Is Bigger Better?

[alaskanativeson]

I have been a fan of blowguns ever since I was a kid and I read those ads in the back of Boy's Life and Soldier of Fortune magazines for "House of Weapons" in Provo, Utah that had a picture of a guy holding up an anteater supposedly killed by the blowgun. I eventually bought one, and I had a lot of fun shooting at squirrels and starlings in our backyard. I remember the one I had was .40 caliber made of aluminum with a black rubber mouthpiece.

Today the only blowguns I can think of being sold commercially are the ones from Cold Steel. I'll admit, I've really been impressed with Tim Wells and the things he kills with the blowgun (like a big male baboon.) I notice they have two sizes: One is .357 diameter, and the big one they brag about is .625 caliber. The bigger one is the one that has all of the broadhead darts available, along with several other kinds. That is, I think, the one Tim Wells uses.

Correct me if I'm wrong, but shouldn't the smaller one be more powerful? It's not like a gun, where you want a bigger diameter bullet to make a bigger hole, even the biggest broadhead dart they make would fit inside the .357 tube. Since the velocity of my breath is what makes it go, it seems like the .357 one would develop more velocity, because my breath fills the larger blowgun with the same amount but the smaller tube would push the dart out faster.

Am I missing something?

 

[JShirley]

No, I think you're correct. The air "charge" doesn't change.

I've used various blowguns over the years. The factory ones usually had plastic beads that a clipped piece of drawn steel was fitted into. The beads' hole was slightly smaller than the steel diameter, so one end of the steel would be heated, then the heated end pushed into the bead. The plastic would melt enough to allow the steel to be seated, then cool, holding the steel.

I've seen home-made darts made from needles, matchsticks, tape, and cotton balls (these are lightweight, and lose velocity quickly). I've made my own blowpipes using conduit, and made darts from triangular paper cups and screws.

 

[Jim Bowie]

The right size wire nuts work good for ammo.

 

[KevininPa]

The right size wire nuts work good for ammo.

You sound like an electrician. Or at least a guy who's been around them on job sites.

 

[glistam]

I have several blowguns I use, both 0.40 and 0.625 caliber, mostly target practice and occasional pest control when the neighbors aren't looking. I recall people debating fiercely if you produce greater velocity for the larger or smaller, but haven't done any definitive objective testing. If I remember right, it's not so simple to answer. While a smaller caliber means less breath is needed to produce the pressure, the manner in which you breath into it changes slightly. I noticed this with playing musical instruments, it takes difference muscles and more effort to force air though a smaller mouthpiece, and so you introduce inefficiency into the system. That could just be me though. Larger calibers also mean you can generally use heavier projectiles, which may be slower but deliver greater impact energy.
I have a set of these 0.625 "plumbata" darts which have better range than most due to their design (most darts use drag as a stabilizer), though I've never tested the velocity or impact force with instruments.
http://www.alcheminc.com/traddarts.jpg

 

[kBob]

A friend had a .40 that had darts with cones for drouges that also had bead type darts. Both of us seemed more accurate with the cones.

when the folks at work offered friend a little teddy bear wearing a company logged vest he was excited. He took the bear home that very evening. He took a couple of pine boards and set them at right angles in a corner above a book case and enthroned the bear there. When his word of the day was said on TV or the radio he would take an airgun shot at the little bear from across the room. Soon got to where he only made head shots..... then a lady from work visited and noticed poor teddy with three darts in his head and one through the heart. It was all over the office in a day or two...

another friend that had a number of electronics patents that was working on a Night Vision System in the 1980’s mounted a common laser pointer on his blow gun, sighted the laser to his blow gun with wedges and more duct tape, put his NVS on a head seat and hunted barn rats in the dark. I’d there was not enough ambient light he used the IR light from a Video camera for invisible to rats illumination

years ago one of the survival or back to the woods type magazines had an article about making cone drouge-darts for an electrical conduit blowgun using a pointed chisel heated in a fire to form the cones from old plastic milk jugs and the like. Fortunately for the local ER staff I never got around to actually trying to do that.

-kBob

 

[WestKentucky]

Beer and guns don’t mix, but in college beer and blowguns definitely did. The fan in my buddies apartment wasn’t perfectly balanced and caused the dangling chains to swing. We both got good enough to hit the moving wooden ball at the end of the chain. I have always wanted to buy a blowgun since then but haven’t stumbled across one at a flea market or some such place. More recently I have stumbled across a video of a small bow with what resembles a syringe on it that effectively necks down the air charge to fire a small caliber projectile. Could be really neat to use something like that to fire pellets... kinda a combination of archery, and blowgun.

 

[JohnKSa]

At the same pressure, the larger surface area of the larger diameter dart will mean more force applied and higher velocities--at least right when the two darts start moving as long as they're about the same weight and have about the same friction with the sides of the tube.

But even if the pressure is the same initially, as soon as the two darts start moving, the volume of the area behind the dart will grow a lot faster in the one with the larger bore and therefore the pressure (and force) on the back of the larger diameter dart will fall off a lot faster than with the smaller dart.

That means that at some point--if the barrel is long enough, the smaller dart will probably overtake the larger dart. The question is does that happen before you run out of barrel length. I would think that for very short barrels, the larger dart (assuming about the same weight for both darts) will be faster, but that once you get to much longer barrel lengths, the smaller dart will be faster. The exact break-even point is going to depend on the amount of air the shooter can generate and get into the blowgun in a hurry.

I'm not sure that it's really a very practical question. Just kind of interesting to think about.