Follow along with me and my simple step-by-step instructions. I make learning FUN!!!
First of all, open up the gun and remove the stupid bipod. Done? Good.
Next, dremel off these annoying parts.

They're just going to get in the way of the sliding action.
Next, get some wood that is 1/2" thick. REMEMBER THIS WIDTH! IT'S IMPORTANT! It also must be 3 1/2" wide.

Remember, 1/2" inch! That's the winning thickness. 1/4" is too thin, and 3/4" is too thick. 1/2" is JUUUUUUUST right!

This is the wood i used. The beveled edge at the bottom is nice for the gripping edge. Straight edge would work fine, you'd just need to take the time to really round it and make it comfortable.

To measure, line up the edge of the wood with the little edge that is on the bottom of the word "Longshot CS-6" on the gun, and the straight edge of the wood flush with the end of the gun. Hold it tight there. Next take a marker and mark the bottom of the orange bolt slide enough so there's some clear residue on it.

With the wood properly lined up, stab the bolt through so that it leaves a mark on the wood to mark where the hole will be drilled.
Note: The slide should be in the FORWARD position. FORWARD!
from there, you should be able to make a stencil of the foregrip's shape.

Ignore the marks on the wood. They're from long ago and won't hinder the performance of the grip. Just focus on the stencil shape. The main arm of the grip is 1 1/2" on my gun, and the bottom of the grip is 5" long.
Cut it out, and you should have a shape like this.

Take that piece and use it as a stencil for the other half. You should now have two mirrored pieces.

Drill out a hole where you made a mark with the marker before. Mirror this on the other piece.

The size of the hole should be fairly small. We'll make it bigger later.

Next, find a nail that fits really well through the hole for the sliding mechanism. It should be around 3 1/2" long or longer.
CONTINUED ON NEXT POST
~TCIND
Now, drill the hole larger so that it fits the nail TIGHTLY. Now slide all the pieces together.
It should look like this.

Now’s going to be the hard part. You need to drill a hole in the plastic case. It doesn’t need to be real big, but you need to be able to poke something like an awl through it.
Line up the hole with the gray part of the grip. Have it be about a little less than 1/2â€, but MAKE SURE THEY ARE IN THE SAME PLACE ON BOTH SIDES if you want it to slide smoothly. Now stick the awl through the hole, and mark the place on the wood. Slide the grip into the back position, and mark there. You should have two marks that are on both ends of where the grip will slide. Drill holes at the two points.

Do the same for the other piece.
Now if you have a fancy-pants saw (I think it’s a scroll saw) connecting these two dots should be a piece of cake. Everyone else will have to do it the messy way. Play connect the dots with your drill until you get most of the line.

Now dremel between the dots and smooth it out as best as you can.

Now get a second nail. Widen the hole you made before so that the nail can fit through. Attach the wood pieces and give it a try. It likely won’t be very smooth at first. Dremel the rough parts out until it slides back and forth well.

Now cut a two pieces of wood out of standard 1†wood (actual thickness 3/4â€. Calling it 1†is v ery silly.) One should be 5†by 2 1/4â€, and the other 1†by 2 1/4â€.
For the larger 5†piece, you need to cut a notch in it so it will be able to slide back and forth easily. I found that around 1/2†on both sides, and a little more than 1†on the front works well. I rounded it also, but it’s not necessary.

Next, take the 1†piece you cut, and screw it on top. Pre-drill your holes and countersink the screws for best results.

Now, using clamps to firmly keep it in place, nail the side pieces to the grip part you just made. 2†finishing nails worked well for me.

I also put 2 1/2†brads (really small finish nails) in at the back for extra support.
Do that to both sides, and you’re done!
For extra credit, make pencil marks like this, and make a diagonal cut along that line. It’s just for aesthetics, do it if you want.

Sand it smooth, give it a nice paint job, and show it to your friends. You’ll be the bell of the ball. Or something.
Any questions/ comments?
~TCIND