Find contentWhen I first did this mod, I had the problem of the entire barrel shooting off the gun when I pulled the trigger (I wanted a breach-loader, not a muzzle-loader, so I didn't glue it to the gun). To fix this, I added male and female threaded adaptors to the barrel and wrapped them to the other bits with e-tape. However, having to screw and unscrew the barrel to load a dart really cut down on my rate of fire, especially since the threaded adaptors didn't always line up on the first try. I looked at lots of breach systems made by others here, but none that I found locked closed, and I feared that on this gun they would open upon firing, just as my first barrel had flown off.
This design allows the barrel to be unscrewed from the gun and pulled forward, opening the breach. After a dart is loaded, the barrel is pushed back down and secured with a few twists. The breach keeps the barrel in line with the gun, thus eliminating a few seconds of fumbling around. Now I'm sure something slightly faster could be done similar to a bolt-action rifle, but I like the simplicity of this design.
Here is the front of my Big Blast without the barrel or breach:
Since my Home Depot didn't have PVC 1-1/4" to 1/2" socket weld reducing hex bushing, I had to go with a 1-1/4" to 1" plus a 1" to a 1/2". To that I added a short piece of 1/2" SCH 40 PVC and a 1/2" female threaded adaptor which I sanded down about an eighth of an inch (less twisting). These were all glued together using hot glue (after I took the picture).
Here's the barrel:
It's just a 1/2" male threaded adaptor on a length of 1/2" SCH 40 PVC wrapped together with e-tape.Finally, the breach:
The PVC in the middle is 2" SCH 40, with a 2" to 1-1/2" reducing bushing on each end, and a 1-1/2" to 1/2" socket weld reducing bushing at one end. The slots were cut using a 1-1/2" hole saw bit on a drill press to make two sets of holes which were then connected using a hand saw. I also used a spindle sander to smooth the edges somewhat. The 1-1/2" to 1/2" socket weld reducing bushing has the 1/2" end bored out so that the barrel can slide through it easily. I did this with a metal lathe, but I'm sure it could also be done with a large drill bit or a dremel.The final product:
After the barrel is screwed onto the gun, the breach is slid over the barrel and then hot-glued to the body of the gun (not glued in picture). Because the pieces of the breach aren't glued together, they can be pulled off the bushing glued to the gun, thus allowing the attachment of other barrels (I made a quad-barrel attachment that can fit on here. If anyone's interested, I can post a write-up for that later).
So, what do you think? Any comments, questions, critiques, and suggestions would be more than welcome.
