Results 1 to 10 of 10

Thread: BSA 240 Magnum - the way it should have been.

  1. #1
    Join Date
    Nov 2014
    Location
    Maidenhead
    Posts
    10

    BSA 240 Magnum - the way it should have been.

    I bought my first BSA 240 Magnum 20 years ago on a whim. 510fps advertised muzzle velocity (.177) in a compact pistol sounded good on paper and I could see all kinds of applications; target shooting, plinking and more. The one I bought actually lived up to the hype with a velocity of 520fps with Hobbies…if only the practical accuracy had been as good. Initial sub-4 inch groups and it took a couple of hours to consistently hit a coke can at 10 yards. I practised a lot and the groups became tighter but never truly good in spite of a good trigger. It was incredibly hold sensitive and the recoil was very harsh due to the low weight of the pistol.
    A few years later I noticed one day that the velocity had dropped to less than 300fps. It turned out that one of the weak points of this gun is the breech seal (another is the overlever catch). Had the breech replaced and the power went up a bit, though not to 520fps. Took it back to the shop but they only managed to bring it up to 460fps.

    They kindly offered to replace the gun with a new one and I even got to pick the best of the ones they had in stock, which is the one I still have. 505fps so slightly less power than the first one, but far better than the others they had in stock, which only managed 460-470fps. This seems to be the norm for this gun in cal. 0.177 rather than the advertised and much hyped 510fps.
    The second Magnum still kicked like a mule but I enjoyed it for informal plinking sessions and could get decent groups on a good day, albeit always with one or two fliers.
    I then did very little shooting for several years and only recently took it out, only to find that the hiatus had not been kind to it. Chronied it and got about 460fps with 7 grain Gamos (similar to the Hobbies in weight).

    Clarky did a stellar job with my Walther LP-53 so asked him if he was willing to take a look at the Magnum too, which he was. My initial expectations were only to get as much of the power back as possible and perhaps reduce the recoil a bit. I have been in contact with gunsmiths who refuse to work on this gun as it is rather challenging to get it right, but after what I had seen what he did with the Walther I had confidence in Clarky’s abilities.
    He explained in details some of the design flaws of the gun; square spring guide rod, 90 degree transfer port design and possibly also too short barrel in order to give room for the plenum. The last two were not possible to tweak or change, but he started by designing a completely new spring guide for it. The next step was adding a piston weights, gram by gram. Assembly and disassembly, then test it with an added 2 grams until that point of tail off in velocity – very time-consuming. The mainspring was in good condition and they usually last a long time. The piston seal was changed as it was on its way out anyway and the cost is low.

    All along Clarky provided a clear description of the work carried out – his approach was methodical and meticulous and it was clear he has both the theoretical knowledge and practical skills for this task. He returned the pistol in less than a week and advised that the new seal will have a run in period of 300-400 pellets or so.
    As with the Walther, the returned gun looked like a standard Magnum but it during my first session it was clear that this was anything but a standard Magnum. The secondary recoil (piston bounce) was essentially gone and accuracy was improved by at least 50 percent. The twang was gone and the gun felt solid and powerful . I ran a test in the weekend with RWS Meisterkugeln, Falcons and AA’s blue express on target at 8 yards distance and managed 1 ˝ inch groups with all of them and only 1 or 2 fliers. It is still hold sensitive and I need to practise more but this gun is clearly in a different league than the standard gun.

    I then ran all three pellet types through the chrony:

    Meisterkugeln:
    499.7 fps low
    508.2 fps high
    505.2 fps average

    Falcons:
    487.2 fps low
    491.5 fps high
    490.2 fps average

    AA:
    472.4 fps low
    479.3 fps high
    476.0 fps average

    The power and accuracy of this pistol is now what it could and should have been when launched. One cannot help but think how different things could have been, had this been the finished product in the mid-1990’s. Add a longer barrel and better grips and it could have been a serious competitor to the HW45, which I find fatiguing during long sessions due to its weight. Instead it disappeared from the market after 5-6 years and is now becoming collectable.

    It is a flawed design but for reasons hard to explain I always enjoyed shooting this pistol in spite of its shortcomings.
    Thanks to Clarky most of these shortcomings are now gone and it is a real treat to shoot. I am very grateful for the workmanship, time and dedication that went into this tuning and looking forward to tighten these groups even more now.
    Cheers

    Tom
    Last edited by thoro; 22-11-2017 at 12:25 PM.

  2. #2
    Join Date
    Sep 2010
    Location
    Bruton
    Posts
    6,591
    Very interesting, and great that Clarky got that thing working better. These are intriguing guns, in part because of their combination of great strengths and significant flaws.

    You might want quickly to edit the first sentence of your second to last paragraph so as not to risk contravening forum rules on what may and may not be said.

  3. #3
    stagmanv835's Avatar
    stagmanv835 is offline i tend to drink while on the bbs
    Join Date
    Oct 2006
    Location
    Torquay
    Posts
    1,982
    Sounds like a great job done
    You only have the rights you are willing to fight for

  4. #4
    Join Date
    Jul 2013
    Location
    Burnley
    Posts
    1,011
    A good write up, this seems a familiar story a good design made on a shoe string. But can be tuned to perfection.

  5. #5
    Join Date
    Nov 2014
    Location
    Maidenhead
    Posts
    10
    Quote Originally Posted by Geezer View Post
    Very interesting, and great that Clarky got that thing working better. These are intriguing guns, in part because of their combination of great strengths and significant flaws.

    You might want quickly to edit the first sentence of your second to last paragraph so as not to risk contravening forum rules on what may and may not be said.
    Thanks for pointing it out Geezer...appreciated.
    I certainly don't want to break any forum rules so apologies to everyone if I was doing so.

  6. #6
    Blackrider's Avatar
    Blackrider is offline It don't mean a thing, if it ain't got a Spring
    Join Date
    Jun 2009
    Location
    Perthshire the Heart of Scotland !
    Posts
    9,361
    Good OP, very interesting !

    I bought a very nice .22 240 Magnum a while back and was/still am, delighted with it and was hoping it would come close or equal the standards of the HW 45 but sadly is does not. The short barrel length is quite disapointing.
    It is still a handsome pistol though and one well worth collecting !
    “An airgun or two”………

  7. #7
    Join Date
    Nov 2014
    Location
    Maidenhead
    Posts
    10
    Blackrider,

    You don't mention in what way the short barrel is disappointing but I am guessing lack of power. I am sure your BSA could be tweaked to perform as well as mine; after all the internals are identical regardless of calibre.
    I personally prefer both the BSA and the HW45 in cal .177 over .22 as I take a flatter trajectory over slightly more energy, but many others out there would disagree so I guess horses for courses.

    I have got a HW45 as well in .177 and it is a good one.
    I ran the same pellets through the chrony as I did with the BSA and got these results:

    Meisterkugeln:
    586.6 fps low
    594.5 fps high
    592.5 fps average

    Falcons:
    575.8 fps low
    580.7 fps high
    577.4 fps average

    AA:
    537.4 fps low
    549.2 fps high
    548.6 fps average

    It clearly does not like the AAs very much but the other two pellets give great velocity. It is another specimen that actually lives up to the velocity hype; I think Weihrauch states 570fps, whereas Beeman states 600fps for the P1, both usually overrated for most HW45s out there unless they did their testing with very light pellets. Many won't go over 520-530 fps so maybe I was just lucky with mine. It has got the power without dieseling.
    I still enjoy shooting the BSA more (especially after Clarky's tuning); it is lighter and easier to feed pellets into, so not so fatiguing on longer sessions.
    Again, I know many others out there would disagree with me
    Last edited by thoro; 24-11-2017 at 12:03 PM.

  8. #8
    Join Date
    Nov 2016
    Location
    Preston
    Posts
    453
    Cool & very interesting info', sounds like some great work was done on it.

    I have a standard .177 240 Magnum.

    I know it's unpopular & I know it's not as good in many ways as an HW45 (I have one of those too). However despite all that I really do like the thing, it looks great (to my eyes) & for me is accurate enough, also it has real character. That character may come from the fact it is a bit Heath Robinson in design & the grip isn't the best (although I don't mind it overly much) but somehow it just makes me smile when I shoot it !

  9. #9
    Join Date
    May 2005
    Location
    Just north of Bristol
    Posts
    1,691
    I had one of these when they were new out, and I really couldn't get it to hit anything at all. I never got satisfying accuracy out of it. If only... mind I was going from a Gamo PR-45 recoilless pneumatic pistol !

    Glad you have got yours behaving better.

  10. #10
    Join Date
    Nov 2014
    Location
    Maidenhead
    Posts
    10
    It definitely has something that makes me enjoy shooting this pistol more than the HW45, although the latter is superior in most ways.
    And Clarky's predictions regarding the velocity increase also came through.
    Last weekend saw some bad weather so I did not manage to get much shooting done.
    I did,however, manage to run the three ammo types originally tested through the chrony again:

    Meisterkugeln:
    516.7 fps low
    526.5 fps high
    520.7 fps average

    Falcons:
    496.1 fps low
    500.3 fps high
    498.7 fps average

    AA:
    483.3 fps low
    486.2 fps high
    484.3 fps average

    A noticeable difference from when I first got it back (although the velocity figures were very respectable then too). The velocity spread with Falcons and AA's is neglectable. A bit more with Meisterkugeln, but still far better than a standard Magnum.
    This pistol is now behaving beyond anything I could have hoped for and is very pleasant to shoot.

    Cheers

    Tom
    Last edited by thoro; 13-12-2017 at 09:59 AM.

Posting Permissions

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