When I first shot my Big Blast with its PETG breech, the barrel shot halfway out of the PVC. I thought "That can't be good." The I remembered seeing CS's locking breech a while back and made my own locking mechanism. It went great. Until I lent the gun out at a war. When I got it back, the tab used to lock it was gone. I tried multiple tabs, but the all ended up breaking. So last week, I finally came up with a solution to the problem of locking breeches. I present to you: The Couplered Locking Breech. Or CLB for short.
This breech does not require difficult machining processes like CS's slide breech. It just doesn't look as cool. Anyone who has made a simple breech can make this.
-Dremel with cutting wheel
-Your preferred method of cutting PVC (needs to be precise). I use a miter saw.
Completely Unnecessary tools that I used because I wanted to mess around:
-Barrel Material of choice
-1/2" PVC Coupler
-5/8" O.D. O-ring. I think it's #9 at HD. Im not positive. (It just has to fit well in 1/2" PVC
This is what you will be making:
On to the writeup.
Take your PVC Coupler and measure the depth from the end to he ridge in the middle. Mine is about 3/4".
Cut that amount off. Now push any piece of PVC into the coupler with enough force to make it tight; don't push it in all the way. Mark the spot where it stops.
Subtract that from the depth of the coupler and that is the amount of open space the barrel has. For now it will be x. Now we have to do some calculations.
Find the length of the barrel material. Subtract the length of the little piece of PVC we cut earlier, and subtract 1/16" from the ridge in the middle. subtract "x," and now add 1/8," for the o-ring that will go in the back. Once you have that length, cut it from the PVC.
Push the little PVC nub into one end of the coupler. Glue it in place.
Now wrap one end of your barrel in E-tape so it will fit snugly in the PVC.
Also put some other E-tape wrappings on the barrel like you normally would on a breech, except make these a little looser than the one on the end (because they have to slide).
Push the barrel through the coupler and into the PVC, where it should be flush with the end of the little pipe section.
Now glue it.
Now take your O-ring, and put it in the end of the long piece of PVC so it's flush with the end, and glue it.
While that's drying, go ahead and cut the breech opening. Mine's so far up because it's for a BBBB. I'm not going to do this step-by-step because you probably know how to do it.
What I like to do is take the scroll saw and make the vertical cuts so the are perfectly perpendicular, unlike with the dremel, where I'd have to angle it a little because the body gets in the way. Now use the dremel and go to town, and take your files/sandpaper and make it all nice and pretty.
Now that the glue is dry, you can go ahead and assemble your breech. Make sure the back of the barrel is sealing with the O-ring, and you're good to go!
This is what I used it for:
I gotta say I really like the way this looks.
Here it is open:
The whole point of this is to use the front part o the PVC sheath to lock in the coupler, therefore not being able to be pushed out by the air. SO twist the coupler out, insert your dart, and twist it in! It works great so far. I've had no issues. And the O-ring makes for a great seal between barrel and air-output. And it also acts as a dart stop.
Questions or Comments?
If enough people ask, I may decide to sell them, especially because they require some pretty even accurate cuts. I've already been asked via pm by a few people...
Edited by Lt. Stefan, 10 July 2009 - 09:39 AM.