
Start by removing these pieces. To get the boltsled off stick a paper clip in the connection point until the pin pops out. Throw away the two lock pieces, save the springs for spares if you want.

Use pipe cutters to cut the breech along the seam. You don't have to cut it at that particular point if you find another easier.

Sand out the back end until the 17/32 brass can fit through; then cut the front part and use 17/32 brass wrapped in some sandpaper to sand it out until the brass fits snugly in the half piece without warping it. Be sure to mark where the barrel part ends on the front part so you know where to cut the brass later.

Sand your piece of brass so the glue can adhere better and superglue it in the back piece. It doesn't matter how big your piece of brass is as long as it's at least long enough to clear the entire breech.

Then glue the top piece to the brass. Make sure it is pressed as far back as possible, as the original dimensions must be followed.

Bust out your cutting disc and get to work on shaping the brass. Make sure to SAND... lots of sanding. Use the dremel sanding stones on the rough parts then clean it all up with a file. It is especially important to get the pointy part of the brass very smooth and level as to not stab the darts as they come out of the clip. Also important is to get the barrel part of the brass the right length and smooth; if it is too long or if it's too rough on the darts you will have feeding problems. Be sure to test it out thoroughly.

And you're done.
I've done this mod on Raiders, Deploys, Longstrikes, and Recons so far with excellent results. I'd guess the range doubled, maybe more. I've sold a few of these to non NIC people and they liked them a lot.
Anyways, hopefully this will help anyone out who wants to have more fun with their reverse plunger blasters. Still safe to shoot indoors and they don't hurt at all, but with the increase in range/velocity it makes things more fun. Questions or comments?