Replacing that awful BSA breech pin with a bolt?

[Hsing-ee]

The above is spot on. The HW system is far superior. Bowkett used to copy it on his BSA Meteor, Mercury, W&S conversions in the 1980's.
The other advantage of the HW system is that the bolt cannot rotate when the rifle is cocked. This results in a "cam" action when the bolt/pin rotates and causes additional problems.

What he said.

I think the conversation between management and the engineers at BSA went something like this -

Management

"Lads, the customers and those picky pricks at the Airgun World are complaining about the jaws spreading on the Mercury"

Engineers "They can buy an Airsporter, mebbe an Airsporter S, if that's the upgrade they're after"

Management "Now lads were're losing out to these German fellows, no-one remembers the War any more, they're buying from them"

Engineers "Send the Peaky Blinders round to that airgun comic, teach them who won."

Management "Fix the jaws spreading on the Mercury, no more out of you or we'll move the operation to Spain"

Engineers "Grumble grumble where's the calipers?"

So instead of designing a good, precise, efficient breech they went with a solution that just 'stopped the jaws spreading'. It's odd because I think the breech lock up on BSA Mercurys and Meteors is really solid while being easy to unlatch, so theres the verticle, but laterally they just couldn't be bothered, twice. Strange British approach to things, so many things like the barrel and overall design were great on the Mercury.

[greenwayjames]

What he said.

I think the conversation between management and the engineers at BSA went something like this -

Management

"Lads, the customers and those picky pricks at the Airgun World are complaining about the jaws spreading on the Mercury"

Engineers "They can buy an Airsporter, mebbe an Airsporter S, if that's the upgrade they're after"

Management "Now lads were're losing out to these German fellows, no-one remembers the War any more, they're buying from them"

Engineers "Send the Peaky Blinders round to that airgun comic, teach them who won."

Management "Fix the jaws spreading on the Mercury, no more out of you or we'll move the operation to Spain"

Engineers "Grumble grumble where's the calipers?"

So instead of designing a good, precise, efficient breech they went with a solution that just 'stopped the jaws spreading'. It's odd because I think the breech lock up on BSA Mercurys and Meteors is really solid while being easy to unlatch, so theres the verticle, but laterally they just couldn't be bothered, twice. Strange British approach to things, so many things like the barrel and overall design were great on the Mercury.

I was told by someone that knows the thinking at the time, pre- El Gamo Anglo/Spanish buyout, was that the vertical lock up due to its design centred the barrel in the jaws when the rifle was cocked so unless it was actively pulled to one side or the other when firing it would not make any significant difference to accuracy.
The barrel vertical lock up design is one of the best of any breakbarrel air rifle. One of many brilliant designs by the late Mr Roger Wacrow.

[Dornfelderliebe]

I am no longer confident to attempt anything engineering related and went to a local engineer with both BSA and HW hinge bolts for a Meteor.
He was unhappy with the amount of metal he would remove for the Weihrauch nut & bolt heads so has gone with the Mercury bolt. It will have to bear against the inside of the folded jaws which I hope will be strong enough for the task.
The bolt and nut heads should sit within the outer curved part of the jaws to prevent crushing when being tightened.

Once the gap between the jaws has been exposed I intend to fill it with liquid metal filler.

In this case the jaws have begun to splay open.

I was confused by the pros and cons of this in earlier posts, would those of you in the know care to comment on this wrt to cam or tightening problems.

I have a couple of shim washers from A bey on standby.I might need an extra washer beneath the bolt end in case the Mercury bolt is too long for the Meteor cylinder, am about to order a new barrel latch pin from Knibbs and to cap it all an extra strong latch spring from Protek all in the hope that barrel lock up will be solid. What can go wrong?.
ATB DFL

P.S He's a shot gunner so isn't phased with being left with air gun parts.

[greenwayjames]

I am no longer confident to attempt anything engineering related and went to a local engineer with both BSA and HW hinge bolts for a Meteor.
He was unhappy with the amount of metal he would remove for the Weihrauch nut & bolt heads so has gone with the Mercury bolt. It will have to bear against the inside of the folded jaws which I hope will be strong enough for the task.
The bolt and nut heads should sit within the outer curved part of the jaws to prevent crushing when being tightened.

Once the gap between the jaws has been exposed I intend to fill it with liquid metal filler.

In this case the jaws have begun to splay open.

I was confused by the pros and cons of this in earlier posts, would those of you in the know care to comment on this wrt to cam or tightening problems.

I have a couple of shim washers from A bey on standby.I might need an extra washer beneath the bolt end in case the Mercury bolt is too long for the Meteor cylinder, am about to order a new barrel latch pin from Knibbs and to cap it all an extra strong latch spring from Protek all in the hope that barrel lock up will be solid. What can go wrong?.
ATB DFL

P.S He's a shot gunner so isn't phased with being left with air gun parts.

Bowkett used the HW system of barrel bolt/locking but didnt use HW componenents. He made an oversize bolt with a flat head instead of a dome and case hardened it. The end of the bolt had a fine thread which screwed into the opposite breech jaws and was locked in position with a flat head screw. The shank of the bolt was slightly shorter than the breech jaw width and the flat head locking screw when screwed into the purpose made case hardened bolt tightened against the jaws.
All included in a 12 ft/lbs conversion including trigger workover and scope stop for £23.50.Those were the days

[Hsing-ee]

Bowkett used the HW system of barrel bolt/locking but didnt use HW componenents. He made an oversize bolt with a flat head instead of a dome and case hardened it. The end of the bolt had a fine thread which screwed into the opposite breech jaws and was locked in position with a flat head screw. The shank of the bolt was slightly shorter than the breech jaw width and the flat head locking screw when screwed into the purpose made case hardened bolt tightened against the jaws.
All included in a 12 ft/lbs conversion including trigger workover and scope stop for £23.50.Those were the days

That said I think a new Meteor Super of the era was about £37. It did give a very lightweight full-power springer for those who could not afford a BSF B55. And made and modified in Birmingham England, which meant something in those patriotic times. Only 'traitors' and the wealthy who are loyal to no-one drove BMWs in those days.

The breech bolt thing for BSA was just embarassing when cheap Commie guns like the Haenal, Slavia and Chinese Arrow and most of the Spanish El Gamo and Norica rifles managed to make ends meet while providing an adjustable breech bolt on their break barrels.

[greenwayjames]

That said I think a new Meteor Super of the era was about £37. It did give a very lightweight full-power springer for those who could not afford a BSF B55.

The Meteor and Meteor Super of the era was the folded sheet steel and brazed cylinder variety pre-Gamo. The lightweight full power seamless tube version came later post Gamo buyout.

[Hsing-ee]

The Meteor and Meteor Super of the era was the folded sheet steel and brazed cylinder variety pre-Gamo. The lightweight full power seamless tube version came later post Gamo buyout.

I meant the Bowkett conversion gave a full-power lightweight. Everyone making 12fpe for by the time Gamo made its first Mock-Meteor ..

[greenwayjames]

I meant the Bowkett conversion gave a full-power lightweight. Everyone making 12fpe for by the time Gamo made its first Mock-Meteor ..

Sorry. My bad

[evert]

I have a couple of shim washers from A bey on standby.I might need an extra washer beneath the bolt end in case the Mercury bolt is too long for the Meteor cylinder, am about to order a new barrel latch pin from Knibbs and to cap it all an extra strong latch spring from Protek all in the hope that barrel lock up will be solid. What can go wrong?.
ATB DFL

The Mercury bolt will probably need shortening and re-threading, I doubt washers will be enough.
If you can get by with washers, you'll have the heads of the bolt and nut protruding from the tube.

[TonyL]

In most peoples' experience, if the bolt wasn't employed and you stuck with the pin, if nipped up in the (padded, of course) vice and, perhaps shimmed, how long until the sloppiness crept back in? Guessing it may come back quicker in the Meteor with the hollow jaws as compared to the Supersport / Mercury? The Supersport jaws do seem somewhat more beefy. Are they slightly less prone?

The only one I had to do many years ago was my ageing, heavily used slabby, blonde Mercury. My current Supersport, which does not appear to have enjoyed an easy like, exhibits no slop at present.

[Dornfelderliebe]

The Mercury bolt will probably need shortening and re-threading, I doubt washers will be enough.
If you can get by with washers, you'll have the heads of the bolt and nut protruding from the tube.

There's only one way to find out, but if they only stick out by a couple of mm I shall be happy. Of course our HW bolts stick out so far you could almost hang your coat off them and it does not cause concern.

When complete I shall bring this to the Bash for peer review.

[Hsing-ee]

In most peoples' experience, if the bolt wasn't employed and you stuck with the pin, if nipped up in the (padded, of course) vice and, perhaps shimmed, how long until the sloppiness crept back in? Guessing it may come back quicker in the Meteor with the hollow jaws as compared to the Supersport / Mercury? The Supersport jaws do seem somewhat more beefy. Are they slightly less prone?

The only one I had to do many years ago was my ageing, heavily used slabby, blonde Mercury. My current Supersport, which does not appear to have enjoyed an easy like, exhibits no slop at present.

Sorry Tony that’s not the point. It’s just the IDEA. It’s like those bloody expensive Brompton folding bicycles where the rear subframe is held under the front subframe just by flipping gravity. Do you have to check your breech jaws every time you go hunting or shoot a match? I don’t know if you’ve ever read ‘Zen and the Art of Motorcycle Maintenance’ but there’s stuff in there that relates to this. Maybe you could get away with this pin if the jaws were massive the pin massive and made to jet-turbine tolerances. But they’re not. ALL of the Mercurys and ALL of the Mk I and Mk II Webley Vulcans and all Webley Hawk rifles I ever came across in the 70s and 80s had wobbly breeches and grouped poorly. I think the difference with your SuperSport is you. In the 70s and early 80s it was the norm to have one rifle and you shot it a lot. You might trade it in for something better but it was usually just one and you’d shoot the shit out of it. I’d sometimes shoot a whole tin of 500 pellets on a Saturday. I’m sure you did too, but I bet now you’ve got more guns than fingers and toes that pin-breech BSA only has the lightest of light duties .. hence the breech stays tight (for now..)

BSA didn’t fit a bolt because it reckoned users would just use open sights, and aside from the Buccaneer and Meteor Cadet with their aperture sights, that worked fine. When scopes came in they just didn’t want to make the guns more expensive at a time they were only able to compete on price, not performance or quality …

[TonyL]

Fully agree, Al.

[evert]

I'll throw in an unpopular experience now:

My rescue Mercury has a quite large fork to barrel block gap, and when squeezed by the bolt,
the forks only contacts the breech block at the front.

Several of my Supersports have very good breech block to fork fit, and have less play than the mentioned Mercury.
And they have been tight for many shots (three of them have seen a lot of use) with proper lubrication and sensible use.

Of course the Meteor is not as durable, but I have one that sees a lot of use and has stayed good for a long time.
But with the number of airguns I have there's a limit to how much use a single rifle sees

[TonyL]

Yes, I'd always wondered about the possibility of the scenario you describe on your rescue Mercury, evert. I guess the solution would be to employ shims as well as the bolt to keep those jaws parallel?