Performance Comparison of Full Caliber Cone-Stabilized Spearhead Dart to Subcaliber Shaft-Stabilized Spearhead Dart

In recent posts I've shown photos of examples of my prototypes of a type of subcaliber blowgun dart that uses a lightweight shaft as a stabilizer, rather than the molded full caliber "cone" stabilizer that most conventional commercial blowgun darts use. To the side and further below are pictures of another example of this type of shaft-stabilized dart. The particular dart shown uses a foreshaft that is made from a sharp-pointed metal rod/shaft taken from a commercially manufactured "spearhead" dart that originally had a full caliber molded plastic cone stabilizer attached at the rear. I replaced the original full caliber cone stabilizer with one of my prototype stabilizer-shafts, made from a section of plastic sipper-stirrer straw. In many of the pictures the shaft-stabilezed prototype dart appears for comparison alongside a full caliber cone-stabilized dart; I shot both darts into plywood for a comparison of performance in accuracy and penetration.

The orange item in the top picture is a type of full caliber sabot with a forward-facing socket for the subcaliber dart to seat within. When launched, the sabot separates and the dart continues alone-- very streamlined with the narrow stabilizer shaft. When the dart and sabot are loaded in the barrel together, pending launch, sometimes I use a magnet to keep the dart from sliding or moving prematurely down the barrel. However, this combination of dart and sabot can also be used without a magnet, as long as I'm careful not to tilt the barrel too far downward. I have loaded the dart and sabot both by breech loading and by muzzle loading. During loading, if not using the magnet, I hold the barrel with the muzzle slightly elevated, so that gravity can help keep the back end of the dart seated within the sabot's socket. If I'm careful, when I'm ready to shoot I can orient the barrel at somewhat of an angle below the horizontal without dislodging the dart from the sabot's socket... friction helps hold the dart in place as long as I don't jolt the barrel or move or swing it too suddenly. Of course, if using a magnet, I can handle the blowgun more freely, and point the barrel straight down if I want without dislodging the dart. Anyhow, even without the magnet I haven't had any difficulty in being able to angle the barrel downward sufficiently to shoot at a target that was about knee high, from 10 yards' distance. So even without a magnet, a target shooter can easily use this kind of set-up to shoot subcaliber darts.

I shot an unmodified, full caliber cone-stabilized "spearhead" dart into quarter-inch plywood from a little over 10 yards, then shot the straw-stabilized "spearhead" dart into the plywood from the same distance. They both exhibited penetration through the plywood, with a small portion of the "spearhead" tip protruding from the far side of the plywood. Accuracy was good with the straw-stabilized "spearhead" dart; I was able to hit my intended point of aim near and to the side of the cone-stabilized dart that was already embedded in the plywood. I've shown pictures of the full caliber spearhead dart and subcaliber spearhead dart stuck in the plywood side by side, with views from the front, back, and side of the plywood to make it easier to compare penetration performance of the darts.

One other note: in some of the pictures you can probably see the "scotch" tape peeling up a bit from where I used it to help hold the straw stabilizer-shaft in place on the metal spearhead rod/shaft. I actually conducted this test a few weeks ago, so the tape is starting to relax its grip.

Some assembled subcaliber blowgun darts with stabilizer shafts made from plastic straws

In the previous post I showed some examples of heads/foreshafts used to make types of shaft-stabilized subcaliber darts for blowguns.

Here I'm posting a few photos showing finished darts, with the plastic straw stabilizer shafts attached at the rear of the head/foreshaft section. The pics include views of a dart made with a finish nail, a couple of darts made with tungsten worm weights, and a dart made with a heavy field arrow point, the last in "seated position" in the projectile engagement socket of a type of full caliber sabot.

Some examples of foreshafts (or dart heads) suitable for use in subcaliber blowgun darts with stabilizer shafts

Seven examples are shown in the above photo of types of foreshafts or heads I have used in prototype subcaliber blowgun darts. The particular subcaliber darts made with these foreshafts/heads were stabilized by a lightweight, hollow shaft extending rearwardly from the foreshaft/head. I will show the shafts and assembled darts, and sabots used to launch them from a blowgun, in other posts. For now, let's take a closer look at each of the dart heads/foreshafts in the above picture.

Starting from top left, and working my way down the diagonal towards bottom right:

1. I modified a Muzzy brand broadhead assembly for a bowhunting arrow to make this blowgun dart component. The modification was simply to leave out the broadhead blades. This particular broadhead, if fully assembled with the broadhead blades, would have a 75 grain mass. With the blades left out, it's quite a bit more light-weight. To make a dart with the modified Muzzy assembly, I shim the threaded screw-in portion at the rear and then slide a section of plastic soda straw, about quarter-inch diameter on. The slight swell in the broadhead assembly right before the rear threaded rod is a bit wider than the cutting diameter of the three cutting edges of the trocar tip. When shot through a tin can, the trocar tip plus the slightly wider rearward portion opened some big holes!

2. This is simply a replacement trocar tip that can be screwed on to the front of a Muzzy broadhead assembly such as shown in (1). This trocar tip, though, is for the 90 to 100 grain Muzzy broadhead assemblies. It has a hollow portion in the back, which is threaded to allow it to screw on to the front of the broadhead assembly. A somewhat narrow soda straw can be inserted into the hollow portion to make a quick-and-easy, lightweight subcaliber trocar dart. Or, to make a more heavy weight dart, a shaft such as a wooden dowel rod, fiber glass rod, or rod of metal can be inserted into the hollow and glued or otherwise fixed in place. With a full caliber fixed-cone dart with a 12 inch wooden shaft, this tip just barely stopped short of passing completely through both sides of a tin can, so further testing with heavier darts is indicated. Fun!

3. This is an example of a screw-in field point for an archery arrow. I believe this is a 75 grain point. A lot of variety of sizes shapes and weights of this general type of field point are available. A straw stabilizer can easily be attached by sliding onto the threaded portion at the rear, with some tape or shrink tubing for shimming if needed. Quite a bit heavier than the modified Muzzy assembly at top, it take a little getting used to, but can be very stable and accurate, not to mention hard hitting, once you've gotten accustomed to it.

4. An example of a different weight/size/shape of the general type of arrow field point shown in (3). This one has more of a bullet-shaped point.

5. A very simple to make foreshaft made from a finishing nail. I often use such foreshafts/heads with the blunt nailhead facing forward in the finished dart. Here, instead of the approximately quarter-inch diameter plastic straws that I use in the darts with the repurposed arrowheads shown above, I use the kind of narrow, approximately one-eighth or one-tenth inch diameter sipper-stirrer plastic straws that are used for coffee drinks. The blunt head performs something like a wadcutter pellet used in airguns, and punches nice holes in a shoot-through target face. Darts made with the narrow sipper-straw shafts are an interesting example of a type of shaft-stabilized low-drag blowgun darts. Even the darts made with wider soda straws have lower drag than might be apparent at first glance, since they are still narrower than the wide stabilizer cones typically used on full caliber blowgun darts.

6 and 7. These two dart heads/foreshafts, like (5), has been designed to accept a narrow sipper-stirrer straw shaft as a stabilizer. These heads/foreshafts have been made by supergluing a small steel brad through the hole in a small tungsten "worm weight" which is repurposed fishing tackle. The tungsten head is heavy and compact, so the weight of the finished dart, with the lightweight straw stabilizer attached, is concentrated very much towards the front of the dart. It's almost like a streamlined pellet with an aerodynamic stabilizer/rudder attached to it on a (relatively) almost weightless lever arm. Custom-made tungsten foreshafts/heads for blowgun darts could be tailor made to the shape, size and weight required for various types of shooting, including target, hunting and flight shooting. Even in fishing worm weights, there's a wide variety of weights/masses available, even lightweight 1/32 and 1/64 oz sizes. So far, I've used 1/8 and 1/16 and have been very pleased with the results. You do have to get used to judging how heavy the dart is, so that you know how strong a breath to use when shooting it... the tungsten heads are very compact for their mass. A variation that I have worked with, and plan to develop more for flight shooting, is an ultra-low drag blowgun dart based on a heavy, compact head like these tungsten heads. In a prototype of an ultra-low drag dart, I took a small tungsten worm weight and glued a section of thin, stiff, light-weight music wire into the narrow hole through the worm weight. When in use (being launched from blowgun), the tungsten head is at the front of the dart, with the music wire shaft protruding backwards to serve as a stabilizer. Although in my tests so far this music wire-stabilized dart did not shoot nearly as accurately as the darts made with plastic straw shafts, the music wire was a sufficiently good stabilizer to keep the dart flying head-first. That degree of stabilization would likely be sufficient for long distance flight-shooting, in which accuracy is not important, but rather how far the dart travels before falling to earth. Meanwhile, the slender music wire should be well adapted to shed drag in flight. By the way, for the dart heads/foreshafts shown in (1) through (7), the straw stabilizers used with them are usually a bit narrower than the widest portion of the head. This helps protect the straw shaft on impact with a target, and makes it easy to seat the shaft securely. The transition from the wider portion of the head/foreshaft down to the somewhat narrower shaft stabilizer may also in certain darts create some drag which contributes to the overall aerodynamic stabilization of the dart.