Tuesday, April 21, 2015

Tacmod 3.1 Progress

Here is what has happened:

Cut up and flattened a whole lot of PVC

Built up the receiver for the flat top. You will see why I laminated 2 sheets shortly.

Seen from inside.

Mocked up rail install.

Flywheel clearance. In the stock RS, the cage is strategically positioned right under the front support for the carry handle. This allows the cage to stick up into the support, without messing up the clean lines of the top of the receiver. Of course, I want to lose the carry handle here, so that is a problem.

I could have left part of the carry handle support intact, but I decided this route with exposing the cage and cutting out clearance in the buildup would be cleanest. I hate those telltale bulges ruining the lines of flat top jobs on these things.

Marking ejection port on the left panel.

Port area cut out on the left panel.

You will see how the rest of everything comes together. I need to be able to topload, since I do scavenge on occasion. Thus the decision to put the port on the left.

Right panel underside with a nice smooth chamfer cut into it to match. You can also see hardware clearance holes for the rail install.

Rail installed with all fasteners. The rail is bolted with 10-24 button allen screws, washers and nylock nuts to a single non-clamshell PVC plate. This is then screwed to the receiver (into the PVC laminates) with 8 6-32 allen flatheads, countersunk. All black hardware.

The underbarrel rail follows a similar pattern. Single layer PVC buildup on the shroud, then a PVC plate with the Magpul rail segment bolted on with its stock hardware.

Mocked up with flashlight mounted:

This thing is SOLID. It already feels great and it isn't even structurally finished. It is also heavy. Heavy is good, nerf guns are too light. I am going to continue on the theme of reinforcing and filling things, especially the stock.

I gave my 552 a try on it. Awesome, as expected.

Not shown, the modified jam door. I fabbed in a charging handle on the side which will allow operating it easily without access to the top, with bonus tacticoolness. I am working on extending the stroke of it as well to make toploading easier.

To do:
Fence magwell
Magwell front
Cage underside bodywork
Fill and finish top rail install
Motor endbell covers
Install arming plug connector
Gut a stock for battery, reinforce and devcon together
Carefully straighten rail installs, adjust the mounting holes and glue the nuts down
Make flash hider
Order switches for FCG
Obtain a Stryfe cage and fly set
Mod cage for Tacmod use
Look into Demolisher Flywheels
Build battery pack
Build FCG
Mod pusher box for 180 motor
Figure out the sling situation (Later?)
Install charging connector
Shorten a Stampede inner barrel to fit
Add magnetic jam door latch
Tag people.

This project has taken on a bit of a SCAR vibe:

It is about time I realized where that cheek rest on the RS comes from. And it is strange that the Tacmod project has gone this direction. I wasn't trying. I was just going for a better superstock rig.

Even before I saw this I was considering adding side rails in their rightful place (up front near the muzzle) too. I think that will definitely happen in the future.


  1. Out of curiosity what are the Stryfe cage and flywheel set for and why are you interested in Demo flywheels?

    1. I do not run Rapidstrike flywheels. Most of the sets I get are shit (mold flash, out of round, unbalanced and noisy) and do not seem to shoot accurately. Neither of my other primaries have them. My Vulture has them and it sprays all over the place compared to either of my others equipped with Stryfe flies.

      I have a set of Demo flywheels because I got a Demo on trade. I am going to try them out. The only other option is Rayven flies and those have too loose shaft fits for 180 service.

      The Stryfe cage is generally easier to install 180 motors, requires no mods to install 180 motors (which should make for a factory precise motor install, thus potentially better accuracy) and has the spring loaded feed guides which theoretically should improve accuracy by centering feeding darts, thus I want to test them.

      Do you see the common theme?

    2. I see the theme. Can't wait to see if there is a gain in Accuracy. I also didn't know that RS flys were that bad off.

      The RS cage sucks trying to get motors out and in. How simply will the Stryfe cage fit in the RS?

  2. That is looking super slick. Really looking forward to the finished product. Detail how you wire the pusher control switch for us?

    1. Of course. I might do a post right now with the Vulture since this unit is a long way from that point.

  3. Great build as always. I'm curious though, why an offset tac light as opposed to an inline one?

    1. The mount was $4.50 and placed the light as close to the rail vertically as possible. I may snag a non-offset mount in the future, but this will do for now.

  4. How did you flatten the PVC?

    1. With a heat gun, some flat objects, and clamps.