bullet comparator measurement question Update!

p5200

Sergeant
Full Member
Minuteman
Jun 23, 2008
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poplar bluff mo.
After using the Hornady OAL/Bullet Comparator gauges per directions, I came up with a reading of 1.803" to the Ogive. Should I take off around .010" or so on that measurement for my loaded rounds to be safe? or, should I take a measurement with a couple more bullets from the same batch first? This is on .223 rem. 55 grain Hornady V-Max bullets and will be used for paper p
unching. Thanks!
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Also, using 25 grains of Hodgdon Varget When I measured 1.803 with my comparator, I must not have put enough tension on the OAL Rod because I measured a couple budget factory rounds and they measured more like 1.881" or more. I would assume factory ammo bullets would be seated with a little distance from the lands to make them safer in all rifles of the same caliber. I took another measurement this time pushing the bullet a little firmer into the lands. This time I came up with 1.925" made a dummy load which turned out to be 1.923" which seemed to chamber fine in my rifle with no hard bolt closing. been thinking about loading a couple rounds at this length and test firing and checking for any high pressure signs. I noticed, the bullet I seated at my first measurement 1.803" was very deep into the casing. Sound like I'm on the right track? Thanks for all opinions!
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Suasponte

Gunny Sergeant
Full Member
Minuteman
Apr 15, 2009
1,592
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Pittsburgh, PA
Re: bullet comparator measurement question

I would make a dummy round at 1.802" and see if it chambers in the rifle! If the bolt closes hard then run it into 1.801 and repeat. Continue to do so until the bolt closes with minimal Resistance.

Terry
 

ChrisGarrett

Gunny Sergeant
Full Member
Minuteman
  • Feb 2, 2007
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    Miami, Florida
    Re: bullet comparator measurement question

    I take 3 or 5 bullets, from a box, depending on time.

    I take the straight gage and place the thumb screw at the 12:00 (relative to the ground) position and measure with bullet 1 and record that, being careful to not jam the bullet hard into the bore, but making sure it's actually touching the lands.

    I then rotate the gage so the TS is at the 9:00 position and measure/record bullet 1 again. Then I put the TS at the 3:00 position, towards me/ejection port (righty rifle) and record.

    I move to bullet 2 and repeat the process above. Then bullet 3 to 5, if you're doing 5.

    I take the bullet 1 data and average those three measurements together, doing the same for bullet 2 and 3. I then average those single bullet averages together, to get a final result.

    The tool isn't 100% repeatable and there's a finesse to it, that you'll acquire over time.

    Take all those bullets you've measured and mark them 1, 2 and 3 in the same order that you measured them. Place these bullets in a ziplock baggie, along with the averages for those bullets and rifle and use them down the road to measure throat errosion.

    You'll remove 3 or 5 bullets, but you'll have a standard that will let you know how much of your throat is being eaten away.

    Chris