Reduce Sized F Class Targets

[K22]

I read the Daily Bulletin of this subject and was curious why the 300 yard reduced target is not proportionally smaller (1/2 ratio smaller) than the 600 yard target, for example:


300 X = 1.42 ; 600 X = 3.00
300 10 = 2.85 ; 600 10 = 6.00
300 9 = 5.85 ; 600 9 = 12.00

 

[chkunz]

It has to do with the size of the bullet hole which is not reduced, to make the degree of difficulty similar.

 

[Ned Ludd]

Some of the 300 yd target rings are proportionally smaller. A 300 yd target that had scoring rings proportional to the 600 yd MR1-FC target for the distance would have X-, 10-scoring rings of 1.50", 3.00". Instead, they are reduced in diameter by ~5%. The 9-ring is reduced by ~2.5%, the 8-ring by ~1.67%, and the 7-ring by ~1.25%. I am not certain why they did not proportionally reduce all the scoring rings equally by the same percentage, but presumably, the reduction in ring diameter increases as the scoring ring number (i.e. 8, 9, 10, X) increases to augment the degree of difficulty at the shorter distance, where F-Class shooters tend to shoot out the 10- and X-rings under most conditions.

 

[kzin]

It has to do with the size of the bullet hole which is not reduced, to make the degree of difficulty similar.

This.
I have the formula somewhere.
It's old enough it's based on a 30cal bullet, not 22

Ideally scoring would be to the center of the bullet hole but that's not practical so we do 'best edge' scoring. This is also why some very small targets have a 'negative' sized 10 dot where you have to shoot out the entire dot(not just touch it) for the score.

 

[Kerry Spurgin]

I have not looked at the values to verify, but what CHkunz mentions is correct the corrent method to reduce a target. first one needs to pick an arbitrary bullet diameter. lets say .30caliber. The objecitve is to make the edge of the bullet just touch the ring a both 600 and 300 yard targets.. since the bullet diameter is constant the 300yd ring needs to offset tighter than just raw scaling by .075". and at 200 yds by .10".

600 yd X ring 3in
Bullet center for an X at 600 yds =3.15in
makes bullet center for an x at 300yds = 1.575in
this the x ring should be 1.575in - .15in = 1.425in

so the reduced target for 300 yd is 5% smaller than raw scaling.

600 yd X ring 3in
Bullet center for an X at 600 yds =3.15in
makes bullet center for an x at 200yds = 1.05in
this the x ring should be 1.05in - .15in = .9in

so the reduced target for 200 yd is 10% smaller than raw scaling.