size of unmarked rifle

Discussion in 'General Rifle Discussion' started by murraywc, May 17, 2010.

  1. murraywc

    murraywc New Member

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    I found several rifle barrels with recievers and bolts in a rental house we owned one was a 03-A3 one was a G33/40 one is a rather large barrel with no markings the bore is .253 and the chamber appears to be a 25-06 what is the best way to find the size. One of our local outdoor centers suggested either take it to a gunsmith or just try a 25-06 shell in it, if it will chamber that is it because it is the largest of the 25 cal shells. Any suggestion.
     
  2. Dr. Marneaus

    Dr. Marneaus New Member

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    Take it to a gunsmith or do a cast of the chamber and have it measured.
     

  3. murraywc

    murraywc New Member

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    what should I do the cast with? and what about the 06 being the largest of the shells?
     
  4. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The G-33/40 is a small ring Mauser action originally intended for the 7 X 57 class of cartridges. It may have been rebarrelled to .25-06, but IMHO this is not a truly "safe" conversion as the .25-06 has higher operating pressures than the 7 X 57.

    Have a gunsmith make a chamber casting with Cerrosafe to get the answer.
     
    Last edited: May 18, 2010
  5. c3shooter

    c3shooter Administrator Staff Member

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    As Robo said. Cerrosafe is a low melt temp material with unusual properties. After it cools it shrinks- so that it may be removed- and then- miracle of miracles- returns to it original size, so you can use a micrometer to accurately measure it.

    Although in a pinch I HAVE plugged the bore, pounded lightweight aluminum foil into the chamber, pushed it out and measured it. But Cerrosafe does much better.