Reply With QuoteI recently bought a test length of nitrile hose and made a new breech seal for my mercury. Works a treat! Only cost a quid off yhe bay and 8ve enough left for another dozen maybe!
Registered User
Advice needed please.
I have a BSA Mercury Challenger & a Mercury S
The Mercury S is like new and probably not been fired in over 30 years.
Both are in .22" and look like they share the same breech seal.
My question is what is the best seal to use from the following:
1, Standard BSA
2, T.R.Robb heavy duty
3, Weihrauch (I'm sure I read somwhere that these can be used & that Venom used to use them but not sure)
4, any other recommended?
Your thoughts please..
Thank you,
Pete.
Last edited by kennp; 16-11-2014 at 07:09 PM.
Where's his User name?
I recently bought a test length of nitrile hose and made a new breech seal for my mercury. Works a treat! Only cost a quid off yhe bay and 8ve enough left for another dozen maybe!
Donald
Muddled
Personally, I would stick with the BSA original. They only coat a few ponds and will last you years. Saying that - Ive got a BSA breech seal in a Venomized HW80.
Ive also replaced the poxy leather breech seals in some of my BSF with one and a half 'O' rings' A half because it has a sloping face.
HTH
Ian
Founder & ex secretary of Rivington Riflemen.
www.rivington-riflemen.uk
Registered User
On my meteor, the HW (77) seal gives a clear power advantage over the BSA.
HTH - JB
Administrator
I find the Weihrauch breach seal gives a better seal than the grooved BSA seal.
In the early editions of Airgun Shooter where Steve Pope wrote the workshop section he found that the Weihrauch seal gave 1/2 ftlb more power than the BSA seal.
All the best Mick
Muddled
Originally Posted by T 20
I find the Weihrauch breach seal gives a better seal than the grooved BSA seal.
In the early editions of Airgun Shooter where Steve Pope wrote the workshop section he found that the Weihrauch seal gave 1/2 ftlb more power than the BSA seal.
All the best Mick
Why has the standard BSA seal got a nick/groove in it?
The HW77 breech seal has a grooves all the way round its circumference. I use a '80/35/85/95 ...... non grooved seal and have had no problems.
ATB
Ian
Last edited by I. J.; 16-11-2014 at 10:50 PM.
Founder & ex secretary of Rivington Riflemen.
www.rivington-riflemen.uk
Even better looking than a HW35
As already said above, I have HW seals on my Merc and challenger, seem to seal a lot better and all the BSA seals I've had to dig out after they've gone brown, hard and crumbly.
Pete
Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in
Administrator
I've no idea why BSA put the groove in Ian --- it could be something to do with how they're formed.That explains why there is a BSA breech seal in my Venon HW.
Why has the standard BSA seal got a nick/groove in it?
The HW77 breech seal has a grooves all the way round its circumference. I use a '80/35/85/95 ...... non grooved seal and have had no problems.
ATB
Ian
The 77/97 seal has the groove round the middle so that it can deform when compressed, the break barrel seal doesn't need this groove.
I find the break barrel seal works well in 77s and 97s if there is a bit of play in the cocking linkage and makes up for the wear.
All the best Mick
Registered User
Looks like the Weihrauch Breach seal may be the way to go but has anyone had any experiance of the T.R.Robb breach seal?
Thank you for your replies.
Pete.
Administrator
Hi Ken
I have a feeling the red seals that John Knibbs sells are made by T.R Robb --- if so the breach seals are very good but I'm not too keen on the red piston seals.
All the best Mick
Registered User
I reckon the nick in the BSA seal is to allow air to escape when inserting it into the recess on the barrel.I've no idea why BSA put the groove in Ian --- it could be something to do with how they're formed.
The 77/97 seal has the groove round the middle so that it can deform when compressed, the break barrel seal doesn't need this groove.
I find the break barrel seal works well in 77s and 97s if there is a bit of play in the cocking linkage and makes up for the wear.
All the best Mick
atb
Max
Plinkerer and Tinkerer
Muddled
Could be - but why then doesn't the HW ones have that 'air release' nick?
Founder & ex secretary of Rivington Riflemen.
www.rivington-riflemen.uk
Registered User
Ahh well, them Germans dont think of everything y'know! British Engineering!Could be - but why then doesn't the HW ones have that 'air release' nick?
Also, Theoben breech seals are just an o ring but have a small nick in for what I believe to be the same purpose.
I think the std seal is fine for the BSA. I take with a pinch of salt the 1/2 ft lb increases. My recently refurbed mercury challenger gives single figure consistency over the chrono, many
readings being the same or within a couple of fps of one another so the new BSA seal cant be that bad!
Plinkerer and Tinkerer
Registered User
on my lightning se i fitted a hw seal as id been advised it could help cure the slightly wobbly breech,it did and its now spot on with no play,
Registered User
The nick in the BSA seal is supposed to allow it to expand hard against the side of it's recess under the influence of the HPA when it's fired, & thus provide a better seal - at least that's the theory.
I tried an HW seal once, it's a bit deep & needs trimming so I cunningly put about a mm shim in the recess, put the seal in backwards & sliced it off nice & square - then found it was in so tight I damaged it trying to take it out, so they are a bit deep & maybe a touch wide, they are noticeably good quality though.
Posting Permissions
