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Barrel Size Confirmation

littlebud
In attempting to sell my rifle on gunbroker.com an interested buyer (I hope) wants to know the muzzle wear and the breech wear on my semi-automatic.

I plan to use a telescoping gauge to feel for the inside diameter at the muzzle (horizontal and vertical directions) and gauge the size using a dial caliper.

As a machinist I do this in boring for pressing bearings or pins. Is this what a GUNSMITH would do if asked for the above information? It makes sense, but I'm no gunsmith and I could misinterpret what is requested of me. Trying to get into a gunstore these days and ask this question is more than an hours wait in line just for the facts.

I appreciate any help, thanks.

John Johnson
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Comments

4 comments

Date Votes
  • MIKE WISKEY
    if this is a m-1 garand there are 2 specific guages used to measure this, if it is not a m-1 the measurements do not apply and a general discription is the best you can do.
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  • jonk
    With all due respect to Mike, this applies to more guns than the M1. I've seen gauges for 03 springfields, M1As, AR15s, and even Mausers.

    Yes, there are specific gauges for the M-1 (tapered pin gauges essentially), but the same principle applies. Your muzzle erosion gauge can be used on any .30 rifle.

    To calculate erosion using non-purpose built tools, measure the diameter across the raised portion of the rifling and report that. For instance, it should in theory be .300". .301 would be a ME of 1, .302 would be 2, etc.

    The breech throat erosion will be a bit trickier with no purpose made gauge.

    Edit for Bigloop's post- yes indeed, that would be a gauge for a Springfield 03 or 03A3. Similar ones exist for other guns as well.
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  • BigLoop22
    jonk,

    Is this what you are talking about?:

    1903 Springfield 1903A3 "TE" BREECH BORE GAGE

    http://www.gunbroker.com/Auction/ViewItem.aspx?Item=210619793

    pix925306834.jpg

    pix427215753.jpg

    pix078385510.jpg
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  • nmyers
    A .30 throat erosion gauge will work fine for any M1 rifle, M1 carbine, 1903/1903A3, & many other rifles that are nominally .300" at the muzzle when new. It may not work on an M14-clone (the muzzle brake gets in the way). Your telescoping gauge won't do the same thing, as the TE gauge measures the relative distant inside the bore that it actually measures .300".

    It's far more important, in selling a gun here, to post multiple photos that are in focus, well lit, & close enough to clearly read all markings.

    Neal
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