9 replies to this topic

[Buffdaddy]

In stock form, the Double Down is lucky to reach 50' when angled. The right dart chamber (which fires first if both are loaded) always shoots farther than the left, due to the smart AR design. In fact, the smart AR hinders performance due to the extra dead space introduced. There's simply too much space between the end of the plunger stroke and the darts. So how on earth can we make it competitive for an NIC event?

We double down on this blaster, of course. It just needs more time invested into it.

Before getting to the dissection and modification section, I'll post basic performance numbers here. All test shots were done with Elite streamlines, with at least 30 shots out of each barrel.

-Avg. dart speed - 54 fps (right barrel), 45 fps (left barrel)

Out of the box, with a few screws loose, you can see how simple the blaster is in operation. You prime the blaster like a Nitefinder or Firestrike, and then you pull the trigger.



The plunger follows the style of the Jolt, Triad, Cycloneshock, and other previous blasters. The ridge at the back of the plunger head is what engages the catch mechanism. If it ain't broke, don't fix it, right?


^This was after modification, where I used larger hardware to secure the plunger head.

To start our mod, slice up the plunger tube after removing all the innards. We're going to be replacing most of it. If you wish, you can keep the dart chambers for slapping onto other projects. I chose just to discard them.


I kept the front "rail"/ammo storage piece, and sanded down the top surface until flat. I then added a new plunger tube - a 5" piece of thinwall 1" PVC pipe. I plugged the end with a 1" x 1/2" CPVC bushing, wrapped a couple times with vinyl electrical tape, and super glued into place. Using screws is also a viable option. Hold off on using any adhesives or screws until you know everything fits together!


You also need to drill a 1/4" hole near the rear, for the catch piece to slide through.



I traded the stock spring for one measuring 5/8" OD, 1/2" ID, cut to 5" in length. I believe it came from Menards, but I'll have to check again. The (former) rear of the plunger tube should slide into the new one with a nice friction fit.


You'll be replacing the stock o-ring with a #213 O-ring (1 3/16" OD, 15/16" ID).It may appear loose on the plunger head, but once it goes into the plunger tube, it will compress enough to stay in its slot. I also recommend drilling out the existing screw holes in the plunger and plunger head to allow the use of a 1/4 screw.

Throw everything back together. The original orange pieces of plastic will fit back into their original slots, and the plunger tube should sit on top of everything, in a flat position. If not, then sand down/cut off plastic as necessary to make things fit, Then you can apply your adhesives and plastic epoxies.



How does our newly modded blaster hold up? Very well. Using a 6" length of 1/2" CPVC for my barrel (a well worn barrel that really is .50" ID), I was shooting 100'+ with Elite streamlines. FLAT. On my homemade chronograph, my Double Down averaged 168 fps.


One of the shots from the chronograph, displayed in Audacity.
1.125 ft / (285 samples/44100 Hz) = 174 fps.

I'm sure I could eke out more power if I tested different barrels. But I'm content with a threefold increase in dart velocity.

[Birch]

How much draw are you achieving?

Those fps readings are impressive...not sure I can trust them though. Amazing mod if those numbers are accurate. Could definitely rival some homemade blasters.

[Thorn]

100' Flat consistently? I am not disputing your claims, but a rainbow pistol with a perfect seal and a [k26] can only shoot around 80' flat, so what sets yours apart?

[Buffdaddy]

'Birch', on 18 May 2015 - 01:39 AM, said:

How much draw are you achieving?

Those fps readings are impressive...not sure I can trust them though. Amazing mod if those numbers are accurate. Could definitely rival some homemade blasters.

They're accurate. I have been thorough with testing, though if you like, I can post the raw data after work today. I also will be posting a reworked writeup for my homemade chronograph to help in making things replicable.

'Thorn', on 18 May 2015 - 04:05 AM, said:

I am not a racist, but...

You do know the 'but' pretty much says otherwise about the previous statement, right?

[MAV13]

I may have to pick one of these up, do you think it would fit a length of [k26]?

Also for the future, I'd just not post ranges taken with elites, they honestly mean next to nothing. Stefan ranges aren't particularly useful either tbh. You do have FPS readings though, just make sure when you give those readings you also say what darts were used, I assume elites in this case.

[Daniel Beaver]

The FPS readings sound right to me. Nitefinders with extended draw and spring replacements can achieve similar performance.

[Thorn]

'Buffdaddy', on 18 May 2015 - 1:41 PM, said:

They're accurate. I have been thorough with testing, though if you like, I can post the raw data after work today. I also will be posting a reworked writeup for my homemade chronograph to help in making things replicable.



You do know the 'but' pretty much says otherwise about the previous statement, right?

Haha thanks for changing what I said. I'm just not sure what sets yours apart from other blasters in the same genre that shoot 20' less. Maybe it's the use of elite darts?

Edited by Thorn, 18 May 2015 - 02:50 PM.

[Buffdaddy]

'Thorn', on 18 May 2015 - 7:50 PM, said:

Haha thanks for changing what I said. I'm just not sure what sets yours apart from other blasters in the same genre that shoot 20' less. Maybe it's the use of elite darts?

Haha, I figured I'd have fun with that comment. That's just the first "Not x, but" phrase that came to mind.

I'm not sure what sets it apart. it's a 1" thinwall plunger tube, 2.5" of draw, and a really strong spring. I can't find a spring constant for it, so I may just have to devise an apparatus for measuring that.

EDIT: I fired 12 darts through the chronograph real quick, as I got home late from work. Ran the peaks through Audacity, with a sample rate of 44100 Hz and a sensor gap of 1.125'.

Sample lengths:
284
294
283
333
343
315
291
307
324
295
305
290
Avg: 305.3 samples

1.125' / (305.3 / 44100 Hz) = 162.5 fps

So, well within reasonable deviation of my testing prior to the posting of this thread.

Edited by Buffdaddy, 18 May 2015 - 08:23 PM.

[Birch]

'Daniel Beaver', on 18 May 2015 - 2:38 PM, said:

The FPS readings sound right to me. Nitefinders with extended draw and spring replacements can achieve similar performance.

Good point, I also forgot that he is using elite darts, those are little lighter and more air efficient in terms of initial fps. I guess that is pretty much what this is anyways.

[tomorrowsDarkness]

I warred with Buffdaddy last week and I can vouch for the distance and accuracy. I run a Crossbow with a stock PT and Arrowstorm spring and hit about 80-90 feet with it, and he was outranging me easily. I think my PT needs a little more grease, but he definitely has the range.

It looks super nice in person, too.

Edited by tomorrowsDarkness, 30 May 2015 - 12:46 PM.