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Nail-Dart-Sabot
Posted: Mon Nov 02, 2009 10:08 pm
by dewey-1
Here is a concept drawing I made for BoytonStu.
It is a 2.5 inch serrated nail with a bullet sinker and a discarding sabot for a copper 3/4 inch barrel type M with ID of .811 inches nominal.
The sinker is used to insure a front heavy attitude for flight stability.
Click to enlarge.
Posted: Tue Nov 03, 2009 12:28 am
by Technician1002
Very nice. Should the tail of the round (nail head) be supported to reduce forces on the lead? I could see the sabot and lead launching and leaving the nail behind if the lead slips.
I had a water bottle sabot pass a AA battery in my barrel on a high pressure test shot. The battery has enough mass so the forces were enough for the battery to punch a hole through the sabot. The sabot launched around the battery and left it behind for a low velocity shot.
Posted: Tue Nov 03, 2009 12:49 am
by jackssmirkingrevenge
If you're using a nail made of relatively soft metal, it would help if you hammered the head flat to form a fin.
If you had a heavy duty
chuck and the nail was made of soft enough metal it would be possible to squash the head into three fins in the manner of a "beehive" type flechette:

Posted: Tue Nov 03, 2009 12:49 am
by dewey-1
Tech;
Yes the sinker needs to have a wire soldered in the front and epoxied from the rear once the ideal stability point is found.
I chose a bullet sinker so the center of gravity can be fine tuned by sliding
it forward of center of pressure for the optimum stability.
It is just drawn for some body to build and try.
Posted: Tue Nov 03, 2009 12:50 am
by jackssmirkingrevenge
If you finned the nail in the manner suggested above the sinker would not be necessary and you could make the darts much more quickly.
Posted: Tue Nov 03, 2009 1:17 am
by dewey-1
Forming the fins will be more difficult than you think.
I believe the nails are hardened, I did this as concept for Stu.
I would like to have a hydraulic actuated "heavy duty chuck" for that purpose.
I personally would just buy some fletchettes rather than make them.
Posted: Tue Nov 03, 2009 2:04 am
by Technician1002
dewey-1 wrote:Forming the fins will be more difficult than you think.
I believe the nails are hardened, I did this as concept for Stu.
I would like to have a hydraulic actuated "heavy duty chuck" for that purpose.
I personally would just buy some fletchettes rather than make them.
I've had some exposure to blacksmithing. A cherry hot nail won't take too many hammer strikes to do the job.

Posted: Tue Nov 03, 2009 2:24 am
by jackssmirkingrevenge
dewey-1 wrote:I personally would just buy some fletchettes rather than make them.
Fair point, they're quite cheap and
sold by the pound 
Posted: Tue Nov 03, 2009 6:39 am
by psycix
I'd put the sinker more on the front. And +1 on the fins. However, a piece of duct-tape or rope will also work.
Posted: Tue Nov 03, 2009 6:45 am
by jackssmirkingrevenge
psycix wrote:However, a piece of duct-tape or rope will also work.
... in the same way that a warm wet towel strategically folded would also "work", but hardly as satisfying as a real woman

Posted: Tue Nov 03, 2009 7:25 am
by psycix
What the heck do you use your towels for!?
Actually, I do not want you to answer that question. Go play with your towels or epoxy or something.
I've successfully stabilized a drill bit with a simple piece of rope. Stabilizing is easier then most people think.
Posted: Tue Nov 03, 2009 8:00 am
by boyntonstu
2 issues:
1> Seal round in barrel to receive energy.
2> Characteristics of flight.
For example: Rope stabilize , or fletchette stabilized rounds fly straight but how do you seal them?
Posted: Tue Nov 03, 2009 9:24 am
by dewey-1
The rear seal could be either an o-ring or a flexible flat disk attached near the back of the sabot. I initially considered drawing that it but decided to leave out. I will update the model to show a seal.
A 16 ga shotgun shell cartridge is about the right size for 3/4 in Type M copper barrel. With a rim OD of .815 inch, trim the rim to fit your barrel.
http://www.dave-cushman.net/shot/shotshellloads.html
Go with a pound of flechettes and 16 ga used shot gun shells.
Posted: Tue Nov 03, 2009 9:29 am
by jeepkahn
Ahem.... Read made Nail Flechettes.... Push the orange collar to the back of the nail and if you want to fire out of anything larger than a .40" barrel, make a sabot... However, out of a .40" barrel and 750psi co2, they penetrate to the hilt in 3/16" steel at 50yds, and to the hilt in solid wood at 100+ yds.... How much more do you need??? I do use a 9mm shell casing as a wad...
Posted: Tue Nov 03, 2009 9:49 am
by dewey-1
I was looking for those in the forum discussion but could not find.
Jeep;
Could you get accurate dimensions for me when you have time.
I would like to create a 3D model of it.
Also a closeup pictures of the plastic piece side and front view.