Quick, dirty and simple way to modify a 4B to shoot streamlines or stefans with a breech.
Tools and supplies:
- File
- Hacksaw or pipe cutter
- E-Tape
- Packing tape (the 2" wide variety)
- PETG barrel
- Recon barrel
- Wire tie (such as from a LongShot box)
- Weak spring (like from a Maverick dart peg)
I started with a Lego Atlantis Harpoon Blaster, which is a fancy way of saying 4B.
To keep the pump from rattling, I wrapped some packing tape around the end. The trick here is to wrap it sloppily, so it crushes into the space.
To keep the trigger from rattling, I tied one end with a stray piece of wire (it used to hold a Longshot to the box) and slipped a weak spring between the trigger and forward air reservoir.
I chopped the end off the barrel with the pipe cutter (a hacksaw will do fine.) Then I took my time filing away a breech for it. No dimensions here - just file until the dart can be pushed in.
I'm still working my way through OMC's PETG. Good stuff. This is a 10" length. I have some 12" lengths, but they're not here and I wanted to get something out of this puppy. The guts of the 4B are black, and I don't believe "black guns automatically shoot 20' further." While this is an office toy, I still want it to be obviously a toy. That said, I took a hacksaw to a Recon barrel extension piece and wrapped the PETG with sloppy packing tape. Again, sloppy is the key - this way, the barrel will force the crumpled tape to conform and hold.
The breech is made by cutting a length of PETG lengthwise, snapping it over the 4B's muzzle, wrapping the ends with e-tape to get a good seal and then the whole length of it with packing tape to keep the air from sneaking out the middle.
Here's the completed shot.
Breech open. Note the Recon barrel keeps the breech from sliding forward too far. Also, the PETG need some cramming to fit into the 4B's bore. This does the equivalent of a 'tightening ring' in an Angel Breech - it will seat the dart nice and snug.
The breech doesn't need to open that far to load a dart. Opening it an inch will be enough to angle the dart in, be it Streamline or Stefan.
Breech closed.
Firing grip. The trigger is on the top.
Conclusions:
- It's quick. From start to finish, it took two hours, most of it filing the breech out. With a Dremel, it would probably take minutes.
- It's flimsy. The PETG barrel is just crammed into the 4B muzzle. If I were to take this out to a war, I'd reinforce the joint with some thing. Probably plumbers' goop.
- It's not waterproof. The packing tape turns soggy and sickly-sticky when it gets wet. If this were going to a war, I'd use somethin different. Probably hot glue to round out the cross-section, then e-tape.
- It's ugly. That's a feature. No enclosure, no PJ. It's just done.
- Ranges? We don't say no steenkin' ranges. I don't have a 100' tape measure, but it shot n paces (not specifying what 'n' is, because we all know paces are not a legitimate means to measure.)
Edited by taerKitty, 07 January 2010 - 05:22 PM.
