TAC - Tight arse comparitor

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  • TAC - Tight arse comparitor

    In the spirit of my TAT - Tight Arse Tumbler seen on the 'old site' I have whipped up a comparator. (TAC)
    Comparators are used to measure seating depth at the ogive of the projectile (bullet) instead of the tip so it should measure from the point where the shoulder (ogive) of the projectile meets the lands. This ensures uniform seating depth as most projectiles will vary in overall length, so it's not as accurate to measure top to tail.
    Anyway I went to buy a comparator online, but when I had a look it reminded me of a brass nut I had in the 'plumbing box' down in the shed, so I went investigating.... yep just like a brass nut.
    The nut I found and used is 15/16 but the size doesn't really matter as long as its big enough not to lose and it suits your projectile.
    I am shooting 6mm PPC so I drilled a 6mm hole in the face of the nut and filed the face smooth.

    Click image for larger version

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    That's it as far as construction goes, then just zero your calipers like below.

    Click image for larger version

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    Then insert and measure your round, just ensure the round is held in square to the nut face and you will get a clear measurement each time, here my overall length is 1.672" which will place the projectile 4 thou off the lands, perfect.!!

    Click image for larger version

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    Let me know if you give it a go!