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Expanding Stefans

Or how to eek some extra range and power out of your gun.

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#1 ToxicWaffles

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Posted 07 May 2009 - 01:09 PM

Well, after several months of browsing the site, my account finally validated, so I figured I'd try to make my first post both comprehensible and useful. I also haven't seen this idea posted anywhere, so, while I'm hesitant to call it "original," it's something that I feel could prove useful to someone. Anyway, there's going to be a short introduction, and then I'll get into the (rather simple) process of making my expanding stefans, which I've found add considerable range and accuracy to my guns...

The first modification I did after exploring this site was to modify a Nitefinder I had lying around. I did the typical things: removing the Air Restrictors, replacing the springs with two stronger ones, and giving it a brass barrel (with a breech, but that's a different tale for another day). But I didn't see that much of a range improvement, and I was disheartened.

I later realized the reason was that I was trying to use a 2-BB stefan in a Nitefinder, which was probably a little to much weight for the thing to take. But, at the time, I had no idea. So I looked into other options.

One thing that occurred to me was that, if I could get more of an air build-up behind the dart, I'd get more power and distance. But my darts were already very tight in the barrel, and I couldn't think of anything else to do...until I remembered expanding slugs in firearms, and how the back of the bullet expands to fill the grooves in a rifled barrel.

So I decided to do something similiar. Here's the process I used:

*****

Materials Needed (these should seem familiar <_<):

-Foam Backer Rod (because it fit my barrel perfectly, I used 3/8" FBR)
-BBs (I don't have the exact weight here, as the box was discarded. They are standard steel BBs, as far as I know)
-Hot Glue
-A Sharp Knife
-A Belt Sander (optional)

Process:

-Make your stefans as you usually would. Mine were approximately 1.25" in length, and each had two BBs in the weighted end.

Now comes the new part

-(Optional Step) Get your Belt Sander, and sand down the tip of the glue and the top portion of the dart, rotating the dart as necessary to get an equal removal of material from every side. The end result (sorry for the lack of pictures, but my computer is a piece of garbage and doesn't recognize my camera software) should look something like a traditional bullet: wider at the base, narrower at the tip. Use either the sander or a knife to remove the frayed edges. This isn't mandatory, but I've found it helps darts fit into breeched brass barrels: where the dart would normally require some twisting to fit, it now slides right in. I've also noticed a slight accuracy increase on the darts I do this to.

-Take the finished dart and, using your knife or other cutting implement, cut a single line directly in the middle of the unweighted end. The depth of this cut should be approximately half of the length of your dart. Then do the same on the other axis, resulting in an cross-shaped cut on the bottom of the dart. I've also had luck with a three-cut pattern, with each spoke of the cut at a 60 degree angle.

*****


Now, I suppose you're all wondering (unless you already can predict) what this will do. When the gun is fired, the air strikes the back of the dart, forcing the cuts open, and thus flattening the divided sections of the dart against the sides of the barrel. This makes the dart's grasp tighter, but not tight enough to impede it's progress. Which, of course, means a greater air build-up before the gun fires, translating to increased power and range.

My Nitefinder was firing about 30'-35' with the original 2-BB stefans, but when loaded with the exact same stefans (now with the Expanding Cuts), it was reliably hitting 65'-75' with alarming accuracy. The same happened with my Big Bad Bow, and a second Nitefinder. The increase in power is also staggering: before it felt (at 15') like getting hit with a normal dart. Now it leaves a sizable red mark and stings a bit.

Admittedly, this might be a fluke, or it might be compensating for my rather average stefan-making skills, but I felt that it might at least prove useful to someone, somewhere.

Edited by ToxicWaffles, 07 May 2009 - 01:11 PM.

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#2 lambchop

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Posted 07 May 2009 - 01:40 PM

Wow this is very interesting but doesn't it bring down the durability of the dart? Either way if it works it works. Nice first post.
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#3 minsc

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Posted 07 May 2009 - 01:41 PM

How much affect does sanding the tip versus not sanding it have? It seems like it would take a really long time to make each dart. As long as you don't have a pointed tip, you should be okay in a war. No one is going to be cool with being hit with pointy darts though.

Making a cross shaped cut in the back is something I have done before as well. It helped my stefans stay in slightly looser barrels, but I simply got lazy and switched to cpvc. I have also heard of people melting a hole in the back of the dart with a glue gun, probably to achieve the same intended effect.
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QUOTE(Zorn's Lemma @ Jul 25 2010, 12:18 AM) View Post

You'll do a lot better if you spread the lips with the front. Trying to wriggle the back in there first seems a bit counterintuitive.

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#4 PointBlank

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Posted 07 May 2009 - 01:53 PM

It sounds like something I will want to try.
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#5 ToxicWaffles

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Posted 07 May 2009 - 02:45 PM

Wow this is very interesting but doesn't it bring down the durability of the dart? Either way if it works it works. Nice first post.


The durability suffers slightly, especially with the three cut version. Not enough for it to make a huge difference though.


How much affect does sanding the tip versus not sanding it have? It seems like it would take a really long time to make each dart. As long as you don't have a pointed tip, you should be okay in a war. No one is going to be cool with being hit with pointy darts though.

Making a cross shaped cut in the back is something I have done before as well. It helped my stefans stay in slightly looser barrels, but I simply got lazy and switched to cpvc. I have also heard of people melting a hole in the back of the dart with a glue gun, probably to achieve the same intended effect.


Sanding the tip make my darts slightly more accurate, and it makes them fit easier into the brass I use. It takes a while, and I'm still not sure it's worth it. I don't think skipping that step would make a truly major difference though. And they're not pointed, just thinner at the top.

As for melting a hole in the back, I tried that, and it didn't have the same effect for me. I'm not sure why, but it may be because melting doesn't allow the dart to expand in the same manner.

Edited by ToxicWaffles, 07 May 2009 - 02:46 PM.

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#6 bobafan

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Posted 07 May 2009 - 03:26 PM

The hollow back works for me, this is how mine are.
Posted Image

This is HC foam which is rather spongy, so it easily expands when the air hits it.
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#7 Ice Nine

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Posted 07 May 2009 - 03:49 PM

I would like to dispute your claims, with the extreme amount of scientific evidence I have gathered out in the hall.

Posted Image

I tested your theory with two types of foam, in two different barrels, with two different guns. I used some Log Home gray washer darts I made (two no cuts, two two cuts, two three cuts); I used some Mile High copper BB darts (two no cuts, two two cuts, two three cuts); I used my aluminum Uruk-Hai Crossbow (air output like an airgun, pictured); and I used my PETG (Cx's, not OMC's) G1 Nite Finder.

With both guns, the cut ones performed notably worse. The Uruk-Hai Crossbow hits seventy-five feet with no external bungees and my Log Home washer darts. Tested out over a few shots, this was consistent. The two cut Log Home darts, however, ranged from sixty-eight to seventy, and never reached even the shortest uncut ones. The three cut ones did the worst, one of them barely breaking sixty and the rest struggling to break sixty-six. The results were the same with the Nite Finder, although scaled down to ranges (fifty-five unbanded with Log Home gray uncut, forty-five to fifty with two cuts, and topping out at a whopping forty-seven were the three cuts).

The Mile High was more disappointment. One of the three cut ones veered wildly off to side, which was annoying since my UH Crossbow is usually a very consistent and usable weapon when I use even moderately acceptable darts. Mile High does not work as well in the aluminum, topping out at about sixty-five unbanded for the 'Bow. The ones with two cuts again suffered a five to ten foot decrease, and the three cuts were poor by all data points. The Nite Finder with the Mile High foam was slightly less disappointing, with the two cuts only landing about five to two feet behind the normal darts, and three cuts landing up to seven feet away.

All in all? I'm going to continue with not putting any sort of hole or cut in the back of my darts.
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#8 ToxicWaffles

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Posted 07 May 2009 - 04:57 PM

--Comprehensive Testing--


All I can say is that I'm surprised. For what it's worth, I'm using Home Depot quality Frost King 3/8" Foam Backer Rod, and a brass barrel that is very tight on the darts. I also notice that, from your picture, you appear to be using washer darts (which you said you were) as well as cut darts with holes melted in them as well. I tried a combination of both...it failed miserably. But perhaps your results are different. I don't have enough of an arsenal to do the sort of extensive testing that many of the members of this forum are no doubt able to do.

I'm sorry to hear it didn't work for you, though.
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#9 AJAQ

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Posted 07 May 2009 - 05:17 PM

--Comprehensive Testing--


All I can say is that I'm surprised. For what it's worth, I'm using Home Depot quality Frost King 3/8" Foam Backer Rod, and a brass barrel that is very tight on the darts. I also notice that, from your picture, you appear to be using washer darts (which you said you were) as well as cut darts with holes melted in them as well. I tried a combination of both...it failed miserably. But perhaps your results are different. I don't have enough of an arsenal to do the sort of extensive testing that many of the members of this forum are no doubt able to do.

I'm sorry to hear it didn't work for you, though.



I have noticed a benefit to expanded back darts used with my PETG longshots. Roughly a 10%-15% difference in my experience.

Edited by AJAQ, 07 May 2009 - 05:19 PM.

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#10 lambchop

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Posted 07 May 2009 - 05:27 PM

--Comprehensive Testing--


All I can say is that I'm surprised. For what it's worth, I'm using Home Depot quality Frost King 3/8" Foam Backer Rod, and a brass barrel that is very tight on the darts. I also notice that, from your picture, you appear to be using washer darts (which you said you were) as well as cut darts with holes melted in them as well. I tried a combination of both...it failed miserably. But perhaps your results are different. I don't have enough of an arsenal to do the sort of extensive testing that many of the members of this forum are no doubt able to do.

I'm sorry to hear it didn't work for you, though.



He is using 3/8 foam whitch results in less drag. So because of this it is harder to compare.
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#11 yahman1254

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Posted 04 July 2009 - 12:08 AM

hey guys, i am very new and i was thinking, because i suck at making stefans balanced or non curly-fry the cuts could be better. what i mean is that melting a hole in the back could add to imbalance and the cuts would remove one variable to screw up as far as bad balance. also, i am currently using a crayola barrel which is very snug for 3/8 stefans.
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#12 yahman1254

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Posted 04 July 2009 - 12:09 AM

hey guys, i am very new and i was thinking, because i suck at making stefans balanced or non curly-fry the cuts could be better. what i mean is that melting a hole in the back could add to imbalance and the cuts would remove one variable to screw up as far as bad balance. also, i am currently using a crayola barrel which is very snug for 3/8 stefans.
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#13 white moonlight

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Posted 04 July 2009 - 09:53 PM

Very nice first post.

It seems this could greatly increase range in your guns.

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Edited by white moonlight, 04 July 2009 - 09:54 PM.

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#14 Lucian

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Posted 04 July 2009 - 10:28 PM

Yet again, no one noticed this thread is from May?...
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#15 TantumBull

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Posted 04 July 2009 - 10:44 PM

hey guys, i am very new and i was thinking, because i suck at making stefans balanced or non curly-fry the cuts could be better. what i mean is that melting a hole in the back could add to imbalance and the cuts would remove one variable to screw up as far as bad balance. also, i am currently using a crayola barrel which is very snug for 3/8 stefans.

The hole in the back is so the air hits it and balloons the stefan in the back so it has a better seal with the barrel. It would be a good idea, for example, if your darts fit too loosely in a barrel you had on a springer.

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