SpudFiles

I have scoured the internet and haven't managed to find any breech loading designs similar to this one. Anyways, I was just wondering if this is a viable design, or will leaking be cause for concern?

P.S. I understand O-rings would improve the design, but I don't have access to the proper machinery.

That would work fine. As for access to machinery, you can make O-ring grooves for that purpose with a hacksaw. If not, use electrical tape. If the O-rings don't need to hold pressure, you don't need a lathe.

I made a breech loading gun without O-rings. Works perfectly. There is only a short sec of pressure in there. Not much air will escape, but some will though.

So is this a viable design?

Yea, it looks like it will work, But probly easier to just use one sleeve of pipe. Getting the inner sleeve to slide without the outer moveing mite be hard to do.