Page 1 of 6 123 ... LastLast
Results 1 to 15 of 81

Thread: Replacing that awful BSA breech pin with a bolt?

  1. #1
    look no hands's Avatar
    look no hands is online now Even better looking than a HW35
    Join Date
    Apr 2003
    Location
    Coventry, even closer to Tony L.
    Posts
    12,064

    Replacing that awful BSA breech pin with a bolt?

    Hi all,

    Thinking out loud on this one, I have far too many projects to be getting on with (plus other stuff), but as this would be hopefully getting done (I haven't asked him yet though) by my local guru engineer, I have a BSA Lightning mk1 that I obtained from Chris at one of the bashes, now then if I was to fit a breech bolt, which bolt do you think would be the best to go for, I personally think the BSA one looks neat and tidy and seems to do the job on my Mercury's and Supersport custom but I've read that all it does is pull the breech block to one side of the jaws?, I've seen the HW bolt conversion done on a Mercury, which I expect does the job nicely but looks ugly to me because it sticks out the side and requires the stock to be altered or do I go the Diana route with the hollow pin and bolt arrangement but still does the same as the HW, or is there another bolt setup I don't know about?

    Your thoughts please chaps.
    Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in

  2. #2
    Join Date
    Apr 2012
    Location
    Retford, Notts
    Posts
    35,035
    Get a HW95 breech bolt, nut and shims.

    HW95 cylinder, barrel, piston, end block, Rekord trigger......yep....bin it off and get a 95, Pete.


    On a serious note, although it would entail some re-engineering work, go the HW bolt route.
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 4/5, 2024.........BOING!!

  3. #3
    Join Date
    Oct 2020
    Location
    Eastwood
    Posts
    1,510
    Quote Originally Posted by look no hands View Post
    Hi all,

    Thinking out loud on this one, I have far too many projects to be getting on with (plus other stuff), but as this would be hopefully getting done (I haven't asked him yet though) by my local guru engineer, I have a BSA Lightning mk1 that I obtained from Chris at one of the bashes, now then if I was to fit a breech bolt, which bolt do you think would be the best to go for, I personally think the BSA one looks neat and tidy and seems to do the job on my Mercury's and Supersport custom but I've read that all it does is pull the breech block to one side of the jaws?, I've seen the HW bolt conversion done on a Mercury, which I expect does the job nicely but looks ugly to me because it sticks out the side and requires the stock to be altered or do I go the Diana route with the hollow pin and bolt arrangement but still does the same as the HW, or is there another bolt setup I don't know about?

    Your thoughts please chaps.
    I've got one of each ready for when I find an engineer. The jaws would have enough material to machine out a hole for the BSA bolt. Why doesn't it pull Mercury's out? that seems a bit odd to me.
    I would want the jaws machined on both sides so that the HW bolt would sit as flush as possible then cut to length. I will have to shorten the bolt 'cos it's for a Meteor.
    Last edited by Dornfelderliebe; 17-02-2024 at 08:52 AM.
    The more I think I know, the more I realise the less I know.

  4. #4
    Join Date
    Jun 2012
    Location
    Oslo, Norway
    Posts
    2,769
    Quote Originally Posted by Dornfelderliebe View Post
    I've got one of each ready for when I find an engineer. The jaws would have enough material to machine out a hole for the BSA bolt. Why doesn't it pull Mercuries out? that seems a bit odd to me.
    I would want the jaws machined on both sides so that the HW bolt would sit as flush as possible then cut to length. I will have to shorten the bolt 'cos it's for a Meteor.
    The Mercury bolt does not lock/thread into the breech jaw, it just has a nut and no locknut.
    The result is that the pinch of the locking chisel rotates the bolt while cocking, ant it tends to work loose/unscrew.
    On the HW, the bolt threads into the "opposite" fork of the jaw, so the nut works as a locknut.
    Too many airguns!

  5. #5
    Join Date
    Oct 2020
    Location
    Eastwood
    Posts
    1,510
    Hmm tapping threads eh? I'll go with the HW item.
    The more I think I know, the more I realise the less I know.

  6. #6
    Join Date
    Jun 2012
    Location
    Oslo, Norway
    Posts
    2,769
    Quote Originally Posted by Dornfelderliebe View Post
    Hmm tapping threads eh? I'll go with the HW item.
    The HW version will need a lot more machining.
    The Mercury bolt should be easier to fit.
    Too many airguns!

  7. #7
    Join Date
    Oct 2020
    Location
    Eastwood
    Posts
    1,510
    Quote Originally Posted by evert View Post
    The HW version will need a lot more machining.
    The Mercury bolt should be easier to fit.
    With a Meteor the hollow jaws will need filling and I wonder whether weld/braise or proper metal filler would do.
    Any way the Mercury bolt looks much better.
    The more I think I know, the more I realise the less I know.

  8. #8
    Join Date
    Mar 2009
    Location
    durham
    Posts
    3,460

    Replacing that awful BSA breech pin with a bolt?

    Quote Originally Posted by evert View Post
    The Mercury bolt does not lock/thread into the breech jaw, it just has a nut and no locknut.
    The result is that the pinch of the locking chisel rotates the bolt while cocking, ant it tends to work loose/unscrew.
    On the HW, the bolt threads into the "opposite" fork of the jaw, so the nut works as a locknut.
    Yep it's also a smaller diameter than the pin so would need a sleeve turning up to make it fit, the HW bolt is a much better solution. My 635 magnum i had the nut was always coming loose but the challenger i have now with the same hinge bolt arrangement does not for some reason.

  9. #9
    look no hands's Avatar
    look no hands is online now Even better looking than a HW35
    Join Date
    Apr 2003
    Location
    Coventry, even closer to Tony L.
    Posts
    12,064
    Quote Originally Posted by junglie View Post
    Yep it's also a smaller diameter than the pin so would need a sleeve turning up to make it fit, the HW bolt is a much better solution. My 635 magnum i had the nut was always coming loose but the challenger i have now with the same hinge bolt arrangement does not for some reason.
    Non of the bolts have come lose on any of mine, I just think there may be more work involved with fitting the BSA bolt as where the bolt head and nut are recessed into the cylinder, I think the HW bolt sits on flats on the cylinder but I may be wrong.
    Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in

  10. #10
    Join Date
    Jun 2012
    Location
    Oslo, Norway
    Posts
    2,769
    Quote Originally Posted by look no hands View Post
    I just think there may be more work involved with fitting the BSA bolt as where the bolt head and nut are recessed into the cylinder, I think the HW bolt sits on flats on the cylinder but I may be wrong.
    The HW bolt measures 7mm, the BSA bolts are 6,35mm/.25". So the holes have to be reamed for the HW bolt.
    The HW bolt need extra fine threads cut into one side of the breech jaws.
    The Mercury bolt just needs recesses, definately less work.
    Too many airguns!

  11. #11
    Join Date
    Nov 2008
    Location
    Preston
    Posts
    3,185
    I did the Diana conversion on my lightning xl tac, works perfect, also included some hw99 breech shims in it
    Plinkerer and Tinkerer

  12. #12
    Join Date
    Mar 2009
    Location
    durham
    Posts
    3,460

    Replacing that awful BSA breech pin with a bolt? Your Message

    Quote Originally Posted by evert View Post
    The HW bolt measures 7mm, the BSA bolts are 6,35mm/.25". So the holes have to be reamed for the HW bolt.
    The HW bolt need extra fine threads cut into one side of the breech jaws.
    The Mercury bolt just needs recesses, definately less work.
    Dunno what diameter the hinge pins are but having tried for fit an old .22 mercury barrel on my 635 magnum I can say for sure the breech block hole is too large for the BSA bolt without sleeving the bolt.

  13. #13
    Join Date
    Apr 2012
    Location
    Retford, Notts
    Posts
    35,035
    Quote Originally Posted by Dornfelderliebe View Post
    With a Meteor the hollow jaws will need filling and I wonder whether weld/braise or proper metal filler would do.
    Yes, I had read previously on here that the Meteor has hollow jaws. Crazy.
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 4/5, 2024.........BOING!!

  14. #14
    Join Date
    May 2011
    Location
    Saxmundham
    Posts
    1,508
    Quote Originally Posted by evert View Post
    The Mercury bolt does not lock/thread into the breech jaw, it just has a nut and no locknut.
    The result is that the pinch of the locking chisel rotates the bolt while cocking, ant it tends to work loose/unscrew.
    On the HW, the bolt threads into the "opposite" fork of the jaw, so the nut works as a locknut.
    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.

  15. #15
    Hsing-ee's Avatar
    Hsing-ee is offline may also be employed in conjunction with a drawn reciprocation dingle arm, to reduce sinusoidal repleneration
    Join Date
    Dec 2001
    Location
    Glasgow
    Posts
    18,244
    Quote Originally Posted by TonyL View Post
    Yes, I had read previously on here that the Meteor has hollow jaws. Crazy.
    The Meteor is a miracle of stamped sheet-steel engineering, like the Sten gun of the 1940s. With just the sheet rolled to make the breech jaws theres nothing but a Void between the breech faces and the cylinder side wall.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •