Breech Seal-An easy solution

[Basu]

The local made Air Rifles at times suffer from poor breech sealing thus causing shot to shot inconsistency and poor power.
The traditional leather seals are very good in terms of withstanding abuse for years yet not remain effective after a period.
In order to solve the issue of sealing , I bought Welding Hose 8.0 from the market and used its inner rubber to fit in perfectly
at breech slot.
I cut 3.5-4 mm of the hose by knife.
I used flat file to knock off the outer layer of the Hose and then put a little grease at the seal slot and pushed the hose seal
into the slot.Then softly cocked the gun so that the seal got into the slot easily.
Using flat file I allowed 1/2 mm part to remain protruded .
Further I use a bit grease again on the surface of the seal and left the gun normally so that the seal takes its own position.
When I checked the sealing by sucking air from muzzle , the vacuum continued for several minutes.
This is a very successful DIY.

Basu
Cost of Welding Hose 12 inches- Rs 18/-

[brihacharan]

> Great job Basu
> My personal experience too...
> However I bunged in a 0.5mm thin metal washer into the breech & then put in the seal...
> This way the seal is ensured of a "level" seating in the breech....
> Since then have put in over 1500 pellets without any loss in fps
Briha

[Basu]

Thanks Briha,
Surely metal sim could be a better option.
I had used this seal in National-25 and fired
5000 shots but yet the sealing is absolute.
Previously I tried to use Suraksha domestic
gas tube.I found that too hazadous to cut and
remove the steel net from the tube.
A word of caution-A continuous lubrication is
required till the rubber takes its position otherwise
the lateral pressure may cut the rubber and
destroy the whole effort.
This seal offers an optimum solution for compression.

Basu

[bennedose]

What is welding hose?

[skeetshot]

Great idea.

Well done !!

[Basu]

Welding hose is the rubber tube made of two layers of rubbers separated by nylon threaded net .
This is used by welders to transfer compressed oxygen and carbide gas upto the welding torch.

Basu

[prudhviraju]

very good idea, thank you for sharing

[Basu]

Dear prudhvirju,
There was another thread where Suraksha domestic gas tube was used.
I tried first to make seal out of that tube only.
Cutting the tube was a nightmare as the steel net was made of high temper wire.
This welding tube has nylon net only and can be cut by any knife.
Another thing which I noticed that this rubber does not react with oil/grease or depreciate easily.
To find it, just go to a near by welder and ask him where to get this stuff.He will surely guide you.
I got it from Chandni Chowk at Kolkata.

Basu

[prudhviraju]

you are true, thank you very much basu

[targetpoint]

Respected Basu sir,
I tried your procedure with the very same stuff.Initially there was some barrel droop may be due to excess protuberance.I then filed it slowly with flat file after that I carried out the talcum test.And yes my air rifle has again regained its power.Your procedure is not only easy but dependable too.
thanks

[Basu]

Dear Targetpoint,
A little bit of grease or oil to be used till it takes the position.
This is best ever home made seal , I have gone accross.

Basu