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Possibly obsolete through non availability of ammo?


I have been barking enough with the Argentinian Mauser but am now sorely tempted by the 6.5 x 58 Portugese Viguerro Mauser. There are a couple about in original calibre and I'm a sucker for old junk. Only problem is ammo. Can you fireform brass to fit?


I suppose there is a reason that the dies cost more than the rifle but sod that I dont have wall hangers, If I buy it it gets fired! Apparently cartridges of the world reckon its a slimmer diameter case than the x 57 and isnt interchangeable but several posters on other forums seem to think it can be done.
When I'm at home Iwrite on canadiangunnutz.com - this is from a fellow milsupr shooter and might be of some use to you - anyone else who is bored with long posts look away now -

  1. [h=2]6.5x58 Portuguese loading with RL-17 powder[/h]
  2. Managed to try some loads with a chrono last night.
    Dealing with rare old calibers with brand new powders can be interesting to find min/max levels.

    Here are the results.

    String: 5
    Date: 12/10/2012
    Time: 11:35:28 PM
    Grains: 140
    Hi Vel: 2433
    Low Vel: 2339
    Ave Vel: 2380
    Ext Spread: 94
    Std Dev: 37
    6.5x58P 39gr RL-17
    Velocity Power Factor Ft/Lbs
    2433 423.342 2286.836
    2402 417.948 2228.932
    2355 409.77 2142.559
    2372 412.728 2173.603
    2339 406.986 2113.544

    String: 6
    Date: 12/10/2012
    Time: 11:44:37 PM
    Grains: 140
    Hi Vel: 2437
    Low Vel: 2398
    Ave Vel: 2416
    Ext Spread: 39
    Std Dev: 17
    6.5x58P 39.5gr RL-17
    Velocity Power Factor Ft/Lbs
    2402 336.28 1793.394
    2411 337.54 1806.858
    2437 341.18 1846.038
    2433 340.62 1839.983
    2398 335.72 1787.426

    String: 7
    Date: 12/10/2012
    Time: 11:45:59 PM
    Grains: 140
    Hi Vel: 2455
    Low Vel: 2437
    Ave Vel: 2446
    Ext Spread: 18
    Std Dev: 6
    6.5x58P 40.0gr RL-17
    Velocity Power Factor Ft/Lbs
    2455 343.7 1873.409
    2450 343 1865.786
    2446 342.44 1859.699
    2437 341.18 1846.038
    2446 342.44 1859.699

    String: 8
    Date: 12/10/2012
    Time: 11:47:44 PM
    Grains: 140
    Hi Vel: 2496
    Low Vel: 2478
    Ave Vel: 2484
    Ext Spread: 18
    Std Dev: 8
    6.5x58P 40.5gr RL-17
    Velocity Power Factor Ft/Lbs
    2496 349.44 1936.506
    2478 346.92 1908.676
    2478 346.92 1908.676
    2487 348.18 1922.566

    40 and 40.5grs of Reloder 17 gave pressure signs of flattened primers

    Bolt is mismatched.

    No accuracy tests yet​
The 6.5X58 has a capacity between the 6.5X55 and the 6.5-06, so you can use 6.5X55 loads as a benchmark. There isn't much in the way of load data for Re17, but there's lots for H4350, and I have found that Re17 is close to H4350 in Burn Rate.

You don't state what firearm you're shooting it in (M1904 Portuguese Mauser?), nor the barrel length, but with that powder and that bullet, 2500 fps would be a modest upper level for MV, and correlate to about 40K psi. The "pressure sign" you're detecting isn't...............

All that having been said, I think you're about where you want to be, and thanks for sharing. I 've shot a grand total of five shots with mine, and never shared the load data - I didn't think anyone would care.


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