R.G. Robinett
"That'll never work."
Having looked up the UBR target size (http://ultimatebenchrest.com/about/the-targets), there is a definite penalty imposed for using a thirty caliber. Historically, BR shooting has been predicated upon center-to-center (CtC) measurement/scoring: groups are measured CtC, and scoring is best edge - both reflect RADIAL scoring. This is logical, since, on any given shot, only the 1/2 of the bullet hole counts.
In score shooting, the actual difference is, thus, the radius compared to the radius - not diameters vs diameter. The UBR page info states: the 30 Cal. ten-ring measures .450", while the 6mm/243 ten-ring is .515. Subtraction clearly results in a diametrically sized difference (.065"), which results in a 0.0325" advantage for the smaller caliber.
UBR is a different game, and not quite what it was intended, or, stated to be. In order to be, "caliber neutral", the difference, in 10-ring diameter, between the 30 vs 6mm, should be .450" vs .4825". Do not misunderstand - I am not saying this is BAD, it's just not comparable to IBS/NBRSA scoring, and, in fact, favors the smaller calibers.
That stated, perhaps someone can/will point out an error in my logic, and convince me otherwise. Keep 'em ON the X! RG
P.S. This egregious, humiliating error, on my part, is so bad, that I wish I could claim to be living in either Colorado, or, on the West coast, and that, I was smoking something. :-(
My blinders were on so tight, that, apparently (obviously) while talking and visualizing radial differences, my bull-headed alter ego added the 0.065 to the 10-ring radius, failing to SEE the math - regrettable, and inexcusable. RG
In score shooting, the actual difference is, thus, the radius compared to the radius - not diameters vs diameter. The UBR page info states: the 30 Cal. ten-ring measures .450", while the 6mm/243 ten-ring is .515. Subtraction clearly results in a diametrically sized difference (.065"), which results in a 0.0325" advantage for the smaller caliber.
UBR is a different game, and not quite what it was intended, or, stated to be. In order to be, "caliber neutral", the difference, in 10-ring diameter, between the 30 vs 6mm, should be .450" vs .4825". Do not misunderstand - I am not saying this is BAD, it's just not comparable to IBS/NBRSA scoring, and, in fact, favors the smaller calibers.
That stated, perhaps someone can/will point out an error in my logic, and convince me otherwise. Keep 'em ON the X! RG
P.S. This egregious, humiliating error, on my part, is so bad, that I wish I could claim to be living in either Colorado, or, on the West coast, and that, I was smoking something. :-(
My blinders were on so tight, that, apparently (obviously) while talking and visualizing radial differences, my bull-headed alter ego added the 0.065 to the 10-ring radius, failing to SEE the math - regrettable, and inexcusable. RG
Last edited: