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B-2 versus B-16?

Posted: Wed Nov 08, 2017 9:50 pm
by mr alexander
The B-2 is the NRA Official 50 Foot Slow Fire Pistol Target while the B-16 is it's 25 yard counterpart.

In 1979, I started shooting Bullseye in a league that held it's matches on a 50 foot indoor range. Ten

years later, I joined a different group that used a 25 yard indoor facility. Several unused B-2 targets

were recently found on a bookshelf. By eye, their bulls now looked exceedingly small. I conducted a

bit of online research on pistol target dimensions and performed some calculations. They were based

on the premise that the B-16's bull was of "standard size". Sparing you the math, here are the results.

The actual 25 yard bull is 5.32" in diameter. So, at 50 feet, the bull's calculated size should be 3.55".

However, it really is only at 3.07", which means that it is 0.48 inches undersize!



In order to keep the challenge/degree of difficulty consistent, I would have assumed that the bulls

would be proportional in diameter relative to the distances that they are engaged at. Apparently,

this is not the case. Is there any legitimate reason why 50 foot matches were made to be tougher

than those that are fired at 25 yards?



P.S. Performing the same math on the NRA Official Sustained Fire Targets also shows similar results. The

50 foot bulls are actually 0.63" smaller in diameter than their calculated sizes would indicate.

Re: B-2 versus B-16?

Posted: Wed Nov 08, 2017 10:24 pm
by spektr
The differences has to do with the projection of the bullet diameters and where the target circles need to be for the same difficulty... When you think about the scale of the target, you ignore she scale effect of the bullet diameter. If the target is half scale, and we are talking smallbore, the bullet becomes twice as large, in effect you are shooting 44 cal scale holes in the target, to compensate, the target circles are moved closer to the center of the bull to compensate for the scale effect of the bullet itself....... Since touching the line is in, and at 50 feet the hole projects larger, the circles shrink......

Re: B-2 versus B-16?

Posted: Thu Nov 09, 2017 12:04 pm
by dronning
spektr wrote:The differences has to do with the projection of the bullet diameters and where the target circles need to be for the same difficulty... When you think about the scale of the target, you ignore she scale effect of the bullet diameter. If the target is half scale, and we are talking smallbore, the bullet becomes twice as large, in effect you are shooting 44 cal scale holes in the target, to compensate, the target circles are moved closer to the center of the bull to compensate for the scale effect of the bullet itself....... Since touching the line is in, and at 50 feet the hole projects larger, the circles shrink......
^^ this and to add, I know quite a few High Masters that have never cleaned a 50' slow fire target.
- Dave

Re: B-2 versus B-16?

Posted: Thu Nov 09, 2017 2:45 pm
by mr alexander
spektr,

Thank you for the explanation; it makes perfect sense. I had no idea that bullet diameter

was being taken into consideration when determining the size of the target circles for the

various distances involved.

Re: B-2 versus B-16?

Posted: Thu Dec 14, 2017 8:19 pm
by perazzi