6 replies to this topic

[sodizzle3113]

First of all I have to say that you should not do this mod unless you are willing to waste a roughcut.
Chief Keener and I worked on this together and we have not gotten very successful ranges out of it, but I will explain that later.

What you will need:
- Rough Cut 2x4
- enough Cpvc to make 8 barrels
- small sticks (we used bamboo kabob sticks)
- 8" of 15/32 brass
- pipe cutters
- Dremel or other way of cutting plastic
- glue
- tape

The Main Blaster:
Take apart the rough cut and do the normal seal improvements, locks removed, whatever.

Then remove the barrels from the front. They are glued on and a little bit of effort will be needed to pry them apart.

The Barrels
First, cut the barrels off at the nub at the base.

like so.
Next take your 15/32 brass

and cut it into 8 one inch sections


Then choose a desired barrel length, and remember what length you chose for later on.
We chose 3" barrels.
Cut up your 8 barrels and get your 8 brass stubs.


Dont put your brass in like this, but this is how the brass is going to sit when the barrel is on it.

Mark off how much of the brass sits in the orange piece. We will be putting the barrel all the way to that line.
Then put the barrel on that line and glue it in like this:

*Protip* put the part that is slightly curled in facing into the barrel so it acts as a dart stop.
Then glue in the barrels, we used hot glue but Goop would probably work better.


The Air Restrictors
This is a very crucial step in the mod. This is what makes the top dart on each side shoot one by one. Or should I say 2 by 2.
Anyways, take your rods and cut them to your barrel length minus the dart length plus an 1/8" to 1/4".
So we used a 3" barrel with 1" darts so the rods were 2 1/4" long.
This insures the darts push back the air restrictors.
So get 8 of those

Next we will cut the nubs off of the AR's.

Then wrap some tape at the end of the stick to make it thick enough to fit in the indented hole on the AR.
Glue them in straight up.


Finishing steps
We had to sand out the orange parts behind the barrels to let the AR's travel smoothly.


Chief Keener also doubled up on the glue for the seal.

Put her back together and it will look something like this:


Final Comments
So the ranges we are getting currently are terrible. 10' to 30'.
But it is using stefans. The stefans have to be a very perfect fit because if it is too loose the AR will push it out and if it is too tight it will not shoot farther than 15"

That is why I labeled it as a proof of concept more than a mod.

Hope you enjoyed, and I look forward to see what you think.

[azrael]

Have you considered using a dremel to cut the brass stubs rather than a pipe cutter? I've always hated the bevel pipe cutters leave.

I had similar results when I rebarreled a Strongarm with polyester tubing, in an attempt to make it rear loading. I only did one, and my range reduction was not as huge, but the stock barrel still performed better.

EDIT: NM, I see you're using the brass as a dart stopper. Is the flaw in this setup, then, a large amount of deadspace?

Edited by azrael, 13 July 2013 - 02:55 PM.

[sodizzle3113]

EDIT: NM, I see you're using the brass as a dart stopper. Is the flaw in this setup, then, a large amount of deadspace?

We believe it is a combination of dead space and low spring power. The plunger rods are odd and only let a very small tolerance for the width of the spring. So we are experimenting with that.

[azrael]

We believe it is a combination of dead space and low spring power. The plunger rods are odd and only let a very small tolerance for the width of the spring. So we are experimenting with that.

I think I've using a 5-6kg Swarmfire spring. Anymore is too much for the gearing system, IMO.

[Ezio Nerf]

I'd suggest using PETG for the barrel material. Looser fit which means it doesn't have as much friction as it would have in cpvc, therefore it might go farther. That's my opinion.

[ShaNayNay]

I think I just figured out why it isn't working.

So, when a dart is loaded, it pushes back the AR and makes a path for the air. When fired, the dart accelerated forward through the barrel, and the AR travels forward with it until it completely seals off the air path. Once this air path is sealed, the dart can no longer accelerate in the barrel as there is no air pushing it anymore. So, all the barrel directly in front of dart once the AR re-seals should actually be decreaing the acceleration of the dart, causing a loss in range.

This makes sense, and if it is correct, one will only be able to make barrels slightly larger than the AR pegs, which is probably why the faux barrels on the Triad and Roughcut work and why rebarrels do not. PETG barrels could possibly work if the dart accelerates faster than the AR closes.

I know none of this as a fact and do not know how to test my theory, but does make sense and could explain why rebarrels aren't working. Perhaps you could make a barrel slightly larger than the AR pegs out of 17/32 brass, then place 9/16" brass around it to create higher quality "faux" barrels, but I don't know if that could get much more than stock ranges.

[sodizzle3113]

I think I just figured out why it isn't working.

So, when a dart is loaded, it pushes back the AR and makes a path for the air. When fired, the dart accelerated forward through the barrel, and the AR travels forward with it until it completely seals off the air path. Once this air path is sealed, the dart can no longer accelerate in the barrel as there is no air pushing it anymore. So, all the barrel directly in front of dart once the AR re-seals should actually be decreaing the acceleration of the dart, causing a loss in range.

This makes sense, and if it is correct, one will only be able to make barrels slightly larger than the AR pegs, which is probably why the faux barrels on the Triad and Roughcut work and why rebarrels do not. PETG barrels could possibly work if the dart accelerates faster than the AR closes.

I know none of this as a fact and do not know how to test my theory, but does make sense and could explain why rebarrels aren't working. Perhaps you could make a barrel slightly larger than the AR pegs out of 17/32 brass, then place 9/16" brass around it to create higher quality "faux" barrels, but I don't know if that could get much more than stock ranges.

That makes an incredible amount of sense. Because there basically isn't a barrel in the stock Rough cut, just the little bit at the end that hold the dart.. so if we were to nest a small amount of brass to make a "dart holder" and then a loose barrel that would make it shoot stefans stock ranges... well hopefully. Basically the only point of this mod was to make a rough cut shoot stefans to be useful in war scenarios.