Rechambering .22 LR to .22 Mag

Discussion in 'Gunsmithing Forum' started by Skribbane, Mar 1, 2010.

  1. Skribbane

    Skribbane New Member

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    Hello all,

    I have a question from across the pond - I'm a student in the UK, so I'm nowhere near as acquainted with terminology as you folks, please forgive me if I'm incorrect in some details :)

    For a recent assignment, I need to reconstruct a crime scene. One of the guns found, a Smith and Wesson 22A, from trajectories of shots, seems responsible for the firing of Winchester Super-X .22 Mag. As far as I am aware, it is not possible for a .22 LR such as the Smith and Wesson to fire .22 Mag rounds, because of the increased length and girth of the cartridge case?

    My question is whether it is possible to rechamber the Smith and Wesson so that it is capable of firing .22 Magnum rounds? If this is possible, any indicator of the complexity of the procedure would be incredibly useful (as this assignment is set in Britain, so the process would be DIY rather than by a professional).

    Thanks ever so much for any help you can give me,

    Jennifer
     
  2. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    IF the round were to be manually loaded (one at a time), it might be possible. The magazine length would preclude the chambering of a subsequent .22 Mag round. It could chamber a follow up .22 LR round, but that round would likely split when fired and not extract/eject properly because of the oversize chamber dimensions.

    The other problem is the blow back mechanism is set up for the recoil impulse of the .22 LR. The Magnum cartridge would blow back at excessive velocity causing the case to be ejected farther than normal. It also would likely open prematurely causing a blown case and possible damage to the gun.

    The bolt could be modified to make it heavier to prevent the premature opening, but that would be an expensive time consuming process.

    Was a fired case recovered? If not then the shooter could have modified the gun to lock closed on the loaded round. This would prevent the blown case scenario and eliminate the evidence at the scene.

    Was a bullet recovered? Is it consistent with the Winchester .22 Mag bullet? Have you looked at the trajectory of a hyper velocity .22 LR round? Look at the CCI "Stinger" round and compare trajectory at handgun velocities. The two may be very close as the Magnum round will lose some of its oomph in a shorter barrel, whereas the LR "Stinger" will not lose as much.
     

  3. Highpower

    Highpower New Member

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    I would also be interested to know what the weight and groove diameter was on the fired bullet, if in fact one was recovered - considering you would have to squeeze the larger bullet (.224) through the smaller (.222) LR bore.
     
    Last edited: Mar 1, 2010
  4. stalkingbear

    stalkingbear Well-Known Member

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    As usual, I was beat to the punch. The Winchester Super X is a true jacketed bullet-unlike all .22LR bullets. It would be remotely possible to convert the S&W model .22A to fire the .22mag in a single shot manner BUT it wouldn't be easy and in NO way be practical. The blow back operation would be a major stumbling block in setting it up for .22 mag pressures. Also the bore would have to be slightly enlarged (both lands & grooves).
     
  5. Skribbane

    Skribbane New Member

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    Hi everyone,

    Thanks for your swift replies! In response to robocop10mm and Highpower, both fired cases and bullets are recovered and definitively stated to be the Winchester Super-X Rimfires - these, to be exact: Winchester Super-X Rimfire Ammunition X22M, 22 WMR, Full Metal Jacket, 40 GR, 1910 fps, 50 Rd/bx

    If the Smith and Wesson fired rounds at all, it needs to have fired two in quick succession, which has to be impossible, taking your collective experience into consideration! I guess I need to rethink the sequence and find an alternative explanation and another (unrecovered) gun... I wonder what the likelihood of someone owning a Grendel P30 in deepest Devon is! :D

    Many thanks all,

    Jennifer
     
  6. Skribbane

    Skribbane New Member

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    Sorry, I seem to have double-posted that reply.

    As an additional query, if any of you are professionally involved in gun modification and you'd be willing to put your name to the above information, would you send me a private message? It would be great to get a "personal correspondence" into the final piece of work if at all possible :)

    Jennifer
     
    Last edited: Mar 2, 2010