How well should a breech loader seal?

[boyntonstu]

I am interested in designing a breech loader and I wonder about the seal.

Obviously, the pilot valve dumps some pressure.

But what about the breech seal?

I built a 1/4" copper barrel gun with a 1/4" pneumatic quick connect as a breech.

Disconnect, and separate the barrel with the attached male connector to load.

The quick disconnect made a tight breech but there was a lot of dead volume.

A break barrel with a union is similar.

Thoughts?

BoyntonStu

[Crna Legija]

Ideally one would want a prefect seal. the quick connect will restrict the flow lots so it will hurt performance. The best is to put a o-ring on the outside of you barrel and have it slid in to a fitting. You could also use a cam-lock

http://www.austrahose.com.au/products/c ... index.html

the break barrel i found its hard make a good seal. Just finished my new canon with break barrel breach, ill post it tomorrow

[boyntonstu]

Ideally one would want a prefect seal. the quick connect will restrict the flow lots so it will hurt performance. The best is to put a o-ring on the outside of you barrel and have it slid in to a fitting. You could also use a cam-lock

http://www.austrahose.com.au/products/c ... index.html

the break barrel i found its hard make a good seal. Just finished my new canon with break barrel breach, ill post it tomorrow

Here is an unusual break barrel with PVC union.


[youtube][/youtube]

BoyntonStu

[Ragnarok]

A breech loader should seal as well as it can - and restrict flow as little as possible.

For your convenience, two early* pictures of what HEAL uses (Sorry, second photo is somewhat blurred):
http://i210.photobucket.com/albums/bb12 ... P01126.jpg
http://i210.photobucket.com/albums/bb12 ... P01127.jpg

*It has been redone more neatly since.

I designed this variant on the popular design for use at higher pressures, and to disrupt flow as little as possible - while keeping dead volume down.
The seal is a pipe into an appropriate fitting, complete with a thick grease - fine for the job, but I suppose it could be improved by cutting a slot into the walls of the "fitting" the pipe fits into so that it seals through an O-ring. Not entirely necessary though.

Ideally one would want a prefect seal

Is that like a Prefect's badge? :tongue3:

[Crna Legija]

that would seal it good, but the point of brech loading is to make it fast.The union takes it away could of just put a sliding barrle and clean up all the junk around the pilot.