6 replies to this topic

[mystefansdontflystraight]

Disclaimer: Deaddumpster did this before me, but never posted a write-up or explictly told anyone how to do it. I got the idea from him, but the write-up is original as far as I know.

This modification will make your ERTL Rapid Fire Shotgun (often referred to as the Doomsayer) shoot harder and further than before.

Materials needed:
-LS plunger tube
-Stock RFDG plunger tube
-Hacksaw/Dremel
-Sandpaper
-Measuring tape
-BBB arrow
-PVC/ABS transition cement

Take the plunger tube out of your RFDG and cut it down like so. Ignore the green thing at the end, that is my plunger tube/turret sealer.


Now, take your stock LS plunger tube and sand off those ridges and that nub that keep it in the LS. Cut it down to 4 7/8 inches.


Now, take your sandpaper and sand out your desired front end of the LS plunger tube. The bit you cut off your RFDG plunger tube needs to fit in there. It won't without a bit of sanding.
PIC

The parts should fit nicely together like this:


Next, take your piece of BBB arrow (thin piece) and glue it into the front of your RFDG plunger tube bit like so. Make a hole for the air to get through. That serves as plunger padding, and it's much easier to add it now.


Next, cement the two together using this stuff:

Your RFDG should fit together with minimal sanding of the ridges keeping the PT in place. I wrapped a shitton of electrical tape around my RFDG plunger head to get it to fit, but if you have tapping bits, I would tap a hole in the end of the RFDG plunger rod and use a LS plunger head replacement. Your RFDG should be shooting considerably farther now. Mine with a stock/BBB spring gets similar ranges to FA_24's that had the stock PT and an extra spring in there. This is easier to prime, and gets similar ranges.

Edited by mystefansdontflystraight, 30 January 2010 - 05:20 PM.

[HOTH]

thats pretty cool. Never thought of anything like that. Do you have pictures of the new PT in the shell? I would be interested to see how well it fits.

[mystefansdontflystraight]

thats pretty cool. Never thought of anything like that. Do you have pictures of the new PT in the shell? I would be interested to see how well it fits.

It's a tad tight, but all the moving parts work well. I'll try to get you a picture. If you cut it down to precisely 4 7/8, there should be no problem. It is a little tight in the shell, so I sanded down the ridges that hold the stock one in place a little. Everything works fine.

[HOTH]

thats pretty cool. Never thought of anything like that. Do you have pictures of the new PT in the shell? I would be interested to see how well it fits.

It's a tad tight, but all the moving parts work well. I'll try to get you a picture. If you cut it down to precisely 4 7/8, there should be no problem. It is a little tight in the shell, so I sanded down the ridges that hold the stock one in place a little. Everything works fine.

Cool. I happen to have mine open, so I have already started

[mystefansdontflystraight]

Well, I made a mistake. You need to sand down those ridges holding the PT in place a ton. My screw ports got stripped from the stress of holding the shell together, so definitely do that if anyone is attempting this.

EDIT: Priming is smoother if you sand down the ridges on the top of the hooded rotation piece, the one that will be touching the PT. This isn't necsessary, but it makes putting the gun back together a lot easier.

Edited by mystefansdontflystraight, 30 January 2010 - 04:54 PM.

[Mr BadWrench]

the usual crossbow internals replacement will also work

[mystefansdontflystraight]

I found a way to get around this whole etape dilemma. The E-tape kept slipping and ruining the seal.
I decided to get rid of the need for etape.
I cut down my plunger head like this

(I removed all the etape first)

I then took a small drill bit and made a hole in the end of the big plastic nub in the middle of the plunger head that keeps it on.

I then made a washer sandwich out of two 1 1/4 inch metal washers and a 1 1/2 rubber one. This makes a perfect seal with the LS plunger tube. Goop your sandwich together. Make sure the rubber washer is centered with the metal ones.

I then took the screw pictured and screwed the whole assembly together so it looks like this.


No ranges as of yet, but I would assume they are very good.

Note that no stress from the spring is being put on the washer sandwich. If you wanted to eliminate some deadspace and elongate the plunger stroke, you probably could, but use legit tapping bits. This screw in the drilled hole will only work if there is no stress on it.