How to determine barrel thread pitch

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  • jstrahl

    Marksman
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    4   0   0
    Oct 22, 2009
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    Franklin
    A couple of months ago I traded for 338 Lapua rifle that has a custom Bartlein barrel on it. I asked the previous owner if he knew what the thread pitch was so I could get the correct brake once I got my suppressor. He was the second owner, but believed it was 5/8 x 24.

    Fast forward to last night and I tried the direct thread module that came with my Hybrid. It would only spin on maybe 2 turns before getting tight and I didn't want to force it and potentially booger something up. I tried it on a barrel that I know is in fact 5/8 x 24 and it went on just fine. I then tried the brake that was already on the custom barrel on the known barrel and it did the same thing, spin on maybe 2 turns before getting tight and going no further.

    Is there an easy way I can figure out what the threads actually are? My first thought was to take the existing brake into a hardware store and see if I could find a bolt that would screw into it. Does that sound like it could work or is there a better/easier way that I'm missing? Thanks!
     

    Backpacker

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    Apr 5, 2008
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    Greenwood
    Use could use a caliper for the diameter and a thread gauge to determine the pitch. It is probably a finer pitch than typical hardware store stock.
     

    Sling10mm

    Expert
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    Mar 12, 2012
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    What Backpacker said, assuming you have these tools, but they aren't that expensive and can come in handy.
     

    jstrahl

    Marksman
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    Oct 22, 2009
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    Franklin
    Thanks guys. I do already have a set of calipers. It looks like the gauge can be had for around $12 on Amazon so I'll just order one. Sadly I couldn't find them on Harbor Freight's site.
     

    praff

    Sharpshooter
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    Sep 26, 2009
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    Thanks guys. I do already have a set of calipers. It looks like the gauge can be had for around $12 on Amazon so I'll just order one. Sadly I couldn't find them on Harbor Freight's site.

    Yep just buy a cheap set of thread pitch gages
     
    Last edited:

    Knight Rider

    Sharpshooter
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    Jan 10, 2013
    411
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    Michiana
    Pitch is just 1/distance between thread peaks. Use the calipers to measure the spread on 10 threads and do the math. 10/measurement = pitch.
    Or use a gage.
     
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