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Nocturnal Specialties
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Discussion Starter · #1 ·
My DPMS lopro 16" bull barrel AR in .223.
55gr Vmax
single bullet hole measured .217" and the Outside to outside of this group measured .480".
Wouldnt the correct way to take .480" and subtract .217"?

100yards

 

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Nocturnal Specialties
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Discussion Starter · #2 ·
Here is my .270s group with some 140gr Berger bullets.




Its shot even better than that with seating the bullet closer to the riflings. Target got wet so its gone bye bye.
 

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You would subtract the bullet diameter not the hole in the target. THat is if the hole was a small round hole with a few shots through it. That group would measure .480 or whatever, but a tape isnt good at measureing sub 1/2 moa.
 

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Discussion Starter · #4 ·
I didnt take a pic of the Calipers. after i measured it with the tape i got to thinking and went and got the calipers and my camera had died.
I thought i had read somewhere when you make the fouling shot of the barrel you aim off center so you can measure that bullet hole. and use that as your subtracter.

Just thought i would try it.

I measured from the dark area where the bullet left some residue on the paper.
 

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I have always been told by benchrest shooters to sub bullet diameter, but your idea doesnt sound bad either. In Action pistol matches they have special guages and scopes to check for 2 bullets through one hole. I dunno but if you are shooting sub half inch then I say your gun is good and you know what your doing.
 

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Two ways.
1)Find the two holes that are farthest away. Measure from the middle of one to the middle of the other.
2)Measure from the outer edge of one hole to the outer edge of the other and subtract the CALIBER you are shooting .223, .264, .284 ect. I prefer this because I can always find the edge but the middle is somewhat more nebulous.
 

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Measure the outside bullet holes from center to center. This is the industry standard way of measuring groups.

Doug
 

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crossedcannons45 said:
they dont make calipers big enough to measure my groups...

I need more range time :(
Tape measures brother. Id welcome you to come shoot, but I dont know how far away Oleput is.
 
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