Page 1 of 1

Barrel O-rings & hammer spring.

Posted: Tue Dec 13, 2016 9:58 pm
by Rocketsuit jim
Hi All,
I've stripped my 410 and found that the O-ring on the brass breech fitting us chewed up & there appears to be one missing in the gap between the brass part & shoulder of the barrel.

So I'm after a couple of these o-rings if available.

Also - my hammer spring is approx 64mm long & 1.65mm dia wire...is this a standard one?

Just tried to upload a photo...do I need to put it on photo bucket or similar first?

Thanks, Jim, Lincoln

Re: Barrel O-rings & hammer spring.

Posted: Tue Dec 13, 2016 10:57 pm
by eboswan
Rocketsuit jim wrote:Hi All,
I've stripped my 410 and found that the O-ring on the brass breech fitting us chewed up & there appears to be one missing in the gap between the brass part & shoulder of the barrel.

So I'm after a couple of these o-rings if available.

Also - my hammer spring is approx 64mm long & 1.65mm dia wire...is this a standard one?

Just tried to upload a photo...do I need to put it on photo bucket or similar first?yep

Thanks, Jim, Lincoln

Re: Barrel O-rings & hammer spring.

Posted: Wed Dec 14, 2016 5:14 pm
by Rocketsuit jim
These o-ring grooves are on the outside of the brass breech tube, that the pellet goes into.
I've had a look online & found lots of O-ring kits for an s410 that seem to go everywhere else but haven't found any that go over the brass tube or barrel to stop air leaking out between the barrel & breech block.

Do AA fit O rings here of should the barrel be glued in to stop air leaking out during the shot?

Thanks, Jim, Lincoln,UK

Re: Barrel O-rings & hammer spring.

Posted: Wed Dec 14, 2016 5:30 pm
by TenMetrePeter
there is no such seal. Just the breech one where the bolt probe goes in and the horizontal one at the transfer port. If the barrel is drastically undersize someone reported using PTFE tape but it should not be necessary. The thing that looks like a groove is possibly the joint between the two brass halves that are loctited together.

ps The transfer port in the brass bit should be at 6 o'clock when the grub screw marks on the barrel are at 12 o'clock . Dont know if folk agree but I might Loctite the brass to the barrel??

EDIT: I stand corrected, O rings (part S650A) are sometimes used where the barrel fit is considered "loose" by Air Arms. You live and learn!

Re: Barrel O-rings & hammer spring.

Posted: Wed Dec 14, 2016 7:31 pm
by Rocketsuit jim
Thanks for the reply tenmeterpeter. I've been scratching my head wondering why I can't see these seals on the parts diagrams. The brass 'barrel shim' as it's confusingly called on a few sites seems to be glued on the barrel I have. There's a groove which has an o ring on it on the other makes of PCP's that I've stripped, and one was fitted to this one but it had been chewed up as a couple of threaded holes go through to this bore.

I'll assemble without seals & do a talcum powder test when it's rebuilt to check for any leaks.

Thanks, Jim

Re: Barrel O-rings & hammer spring.

Posted: Wed Dec 14, 2016 9:56 pm
by Blackbaronfish
The early transfer ports were two piece with the o'ring sandwiched between them. The later one are one piece and the o'ring sits in a groove. Both sort are usually lock tightened to the barrel.

BBF

Re: Barrel O-rings & hammer spring.

Posted: Sat Dec 17, 2016 10:17 am
by Rocketsuit jim
Thanks BBF,
My outer O-ring at the breech end of the transfer port was fairly chewed up & there was no o-ring in the space about 12mm forward of that where there's a gap between the barrel & brass.

I used a tapered reamer & put a very shallow taper over 0.5mm on the breech where the barrel goes in to allow it a small bit of lead in for the O-ring. I've assembled it with a load of thick silicone grease & fired about 30 shots through it to chrono check.

Seems fine... But would still like a couple of O rings to put each side of the transfer port if anyone knows their price or size.

Regards,
Jim

Re: Barrel O-rings & hammer spring.

Posted: Fri Jan 27, 2017 10:20 am
by what barn door
Why not PM Julian, he will quickly advise of the best way forward for this, well he did for me anyway.

Re: Barrel O-rings & hammer spring.

Posted: Fri Jan 27, 2017 10:24 am
by what barn door
In fact read this thread, it will give you the part number and everything else needed.

http://www.airarmsownersclub.com/viewtopic.php?f=8&t=55&start=230