Nail Dart Experiments

[Forum Admin]

Stu sent me some 10 gauge wads and corks to experiment with. I need to build a new barrel before I can experiment with the corks (cant breech load with current setup). The 10 gauge wads are a close fit, just slightly loose, so they drop right down the muzzle. The barrel I used for the experiment is a 29.5" length of 3/4" type L copper. The chamber is a 13.5" length of the same pipe. The valve is a 1/2" qev piloted by a modified blowgun valve. All shots were done at 400 psi.
I used 16d nails that weighed 142 grains apiece. Two of the wads weighed 40 grains, the other was 42 grains. I used hot glue to attach the wad to the head of the nails. The final nail dart weights were 194, 194, and 196 grains. Fairly consistent for something put together with hot glue. 
The first dart went 363.0 fps. The second was 340.4 fps. The last was 498.6 fps, which is a bad reading due to the fact that the chrony was not fully opened. 
I think the problem with low velocity is due to a lot of blowby. Still, 57 fpe is nothing to sneeze at. I accidentally nailed the backstop board solidly to my back deck rail.    lol
Later, I will get another adapter (or just unsolder my current one) that will allow me to friction fit the barrel so I can breech load. I am confident that the corks will produce better velocities inspite of weighing in around 210 grains. They have a near perfect seal, which leads me to think they would make a good piston material for a homemade piston valve.

[Forum Admin]

All right, I finally got a chance to try 4 types of nail darts: cork, 10, 12, and 20 gauge tails. I attached a screenshot of the results at the bottom. So far, it looks like the corks and 12 gauge wads are the best performers. I believe if we can find a easy way to consistently make cork tails and make them aerodynamic that they will be the best performers by a wide margin.

[BoyntonStu]

All right, I finally got a chance to try 4 types of nail darts: cork, 10, 12, and 20 gauge tails. I attached a screenshot of the results at the bottom. So far, it looks like the corks and 12 gauge wads are the best performers. I believe if we can find a easy way to consistently make cork tails and make them aerodynamic that they will be the best performers by a wide margin.

The 10 Gauge results are disappointing.  Shucks!

What was the pressure?

Full ‘quiver’ of nail darts.  10 Gauge wads and corks.

The cork cutting and shaping is getting better each time.



My shooting range behind my friend’s farm.


I shot 3 holes through the plywood in a 6” circle without sights.

Next project:  Sights

[Forum Admin]

The pressure was 400 psi for all shots. I was disappointed in the 10 gauge results as well. They fit too loose in the barrel. The 12 gauge wads are muzzleloaded as well, but I have to blow them down the barrel to get them down. The 10 gauge simply drops right down on its own. 

[FighterAce]

Cool  Good data. Whats the diameter of those 12 gauge wads? And are there any wads that would fit a 12mm or 15mm bore?

[BoyntonStu]

The pressure was 400 psi for all shots. I was disappointed in the 10 gauge results as well. They fit too loose in the barrel. The 12 gauge wads are muzzleloaded as well, but I have to blow them down the barrel to get them down. The 10 gauge simply drops right down on its own. 

I tried separating the 10 Gauge tail sections and flaring them out a bit.

However, until I receive my  Prochrono, I won't be able to tell if it helps.

[Forum Admin]

@Stu - Nice range, BTW, talk about sunny weather. The ground here is covered with about 5" of snow. I havent separated the 10 gauge tail sections, that might make a difference as well.

@FighterAce - 12 gauge wads are ~18 mm. 20 gauge wads are a closer fit to 15 mm, they measure around 15.2 mm. Their ability to fit would depend on the tolerance of the pipe. If you know any trap or skeet shooters that reload, they might have a few they wouldnt mind sharing so you could see what will fit your pipes.

[Forum Admin]

I added a tapered faucet washer to the front of a 12 gauge wad to allow it to be used with a 3/4" type L barrel. It also makes it a tad more aero as well. At 400 psi with a 29.5" type L 3/4" barrel, the 226 grain dart flew at 437.3 fps, which is 96 fpe. I like the fact that they are easy to make, no shaping involved. Just glue on the tail, slip on the washer, and let the glue cool. Does the head make any difference on long term velocity? That experiment remains for another day. Here is what it looks like:

[Forum Admin]

The above dart can pass right through a 2x6 like nothing at 5 yards.   I also have made another dart that works quite well in smaller caliber barrels and requires nothing more than an old t shirt, hot glue, and a nail. I havent been able to chrono it since it is dark, but I took a 20 yard shot and it almost passed completely through a 3/4" piece of particle board. To make, I just cut a square of t shirt material and pressed the nail through the center of it. I then put a dab of hot glue right below the head of the nail and when it is almost cooled, I shape it to be aerodynamic. I then pull the t shirt patch over it and put another dab of hot glue on the head of the nail. Then the t shirt material is pulled and twisted over the glue, keeping it from flaring out too much. Then you just cut any stubborn parts that stick out and your dart is finished. Sounds harder than it really is.   Here's what it looks like:

[Forum Admin]

The small caliber dart (.40 cal) offers pretty impressive performance, especially considering the small bore diameter. The dart weighs 160 grains and travels 449.8 fps (72 fpe) on a 400 psi fill. This is out of a 32" long barrel with a .40" inner diameter. Here's a interesting shot from the 12 gauge with the type L adaptor:

[boar]

the t shirt dart was intresting to me its down side would be the less that perfect seal but it looks like it would stabilize the nail with less drag than a wad or a cork plugso what im thinkin is makin some of these cloth tail darts with the tail just big ehough to stay in the barrel or just big enough to stabilize which ever but as small as i can make it and still work then follow it with a foam plug for a seal ive been playin with blue home foam foe wads for shot loads and seems like it would work for darts i made some darts this evening hmm i think ill go see if it shoots

bbiam
Boar

[boar]

ok i tried it it seems to work shooting 2 darts made the same both at 300 psi from about 10 ft 1 chased with a foam plug 1 just the cloth tail the 1 with the plug went deeper in the plywood than the other i also shot 1 at 50 yds to a lit target i heard it hit somewhere but couldnt find it time of flight seemed too long and i couldnt see how it flew so while it was fun to get out and shoot a bit i was unable to gather any real data

Boar

[Forum Admin]

That is definitely their downside, t shirt material makes a lousy seal. They do stabilize well, so a discarding sabot like a foam disk would probably be the ideal way to maximize power, while the small tail minimizes drag. I hot glued a shotgun primer to the nose of one.  Made a bit bigger hole in my target board than normal and made for an impressive night shot. lol

[Forum Admin]

I had to develop new darts for my coaxial airgun. T-shirt tail darts do not seal well enough in the .545 ID barrel and I dont have any shotgun wads that fit, so I had to come up with something else. I took a short piece of the 1/2" type L copper pipe I used for the barrel and greased it. I centered a nail in it and filled it with 1/4" of hot glue. After it hardened, I popped out the nail. The hot glue makes a near perfect seal, so this should give me optimum power. A tail will stabilize it. I then hot glued a t-shirt tail to it and chronographed it. I got 493.2 fps out of the 174 grain nail dart, which makes 94 fpe. Turns out it has perfect stabilization, even out to 40 yards. It sunk deeper at that range than any of my other dart designs. Here's some pictures including a 40 yard shot into a tree:

[BoyntonStu]

Nice dart.


How does it compare to a cork tail?

Perhaps a mini cork ~ 1/2" for the seal + the T shirt?