TARGET TOLERANCES AND SCORING AIDS
Michael Thomas Niksch – February 23, 2016
Excerpt from Benchrest.com Airgun Benchrest forum
Hi Guys… this is actually a subject that is very near and dear to me. It’s also one which I have spent a tremendous amount of time analyzing.
The first question to be answered is that the scoring dimensions refer to the outside of the scoring ring. Second, since there is no written standard by which we have been instructed to adhere on ring size tolerance of printed targets… the best bet is to get as close as possible. Under a 60x microscope, the latest batch of sanctioned targets are well within .001″ of suggested size in diameter. That translates to less than .0005″ radially… or 1/8 the thickness of sheet of plain printer paper.
I’m not looking to step on any bodies toes here, but measuring the target box and verifying its size only tells you that the target box is the right size. If we analyze the scoring rings by importance, it is instantly clear that the 10 ring is used for the overwhelming majority of scoring decisions. It determines X’s, 10’s, and 9’s… and in a typical competition, these are pretty much all that matter. I’ve heard lots of arguments about how inaccurate manual scoring must be because there is no way to verify concentricity and diameter of the printed scoring rings… so therefore it cannot be trusted. If we think about this a little bit, it’s easy to see that the 10 ring is all we really need to worry about… and since it is the actual aim point it cannot be out of concentricity with itself. It can be too big or too small, of course… but let’s examine that for a bit. Let’s say that we shoot a National event, and the targets used for the event have a 10 ring that is .050″ too big. Please bear in mind that this is a ridiculous exaggeration for the sake of making a point. Will this large 10 ring favor anyone in particular? No… of course not. It may, however, produce scores that are abnormally higher over the entire range of shooters… but it won’t make the competition unfair in any way. Over samples of targets that I have measured from the same batch, I have not witnessed more than .0005″ radial difference in the 10 ring. In any case, I would recommend that targets used for big events come from the same pack… and that would take care of any potential issue that could arise from 10 ring disparity.
Scoring plugs should be .224 head diameter. The scoring plugs that are commercially available for sale are unsuitable for .177 caliber use… because the shank it too big and will open the hole up unnecessarily. Many of us have custom made .224 scoring plugs that were designed for use with .177 pellets and have a shank that is .180″. It’s big enough to insert solidly, but not too big to deform the hole that was made. I have replugged holes 25 times intentionally… to see if I came up with a different answer after replugging… and I do not. It’s that simple.
The scoring plugs with the magnifier built in are essentially crap. They do not compare at all to a solid plug and external magnification. It takes only one time using a good plug and a magnifier box to see this difference.
Along with a proper scoring plug and a good target… you still need other tools to do the job right.
The proper tools begin with a new target backer to support the target and ensure that the holes made by the pellet are as perfect as they can be. A person can (and should) move subsequent targets around on the backer to utilize fresh, unshot, areas to get the most mileage out of each backer if they are not going to be replaced each time. Backers should be something like cardboard, signboard, etc… not wood, or anything that does not allow the pellet to pass through completely and easily.
I would have thought that this next item would have gone without saying… but unfortunately it needs to be said. Target stands should be stationary. It is completely unacceptable for a target to wave in the wind because the stand is too flimsy to prevent it from doing so.
For accurate comparison across the globe… outdoor targets should be 25m from the front of the bench to the target face… indoors should be 25 yards.
Okay… now you have a good target, clean holes, and a plug suited for the job. Now you need magnification, light, and something to keep the target flat and well supported when plugging… and the light should be preferably from the underside of the target for close calls. I have a desk lamp that can be turned upside down… the target holder is then placed on the shade of the overturned lamp to view the shot with a great deal of light from underneath. This light alone will make most close calls a no brainer. Add a 8x slide magnifier box to the equation, and now you have no excuse to make the wrong call. It should be noted that you should be viewing straight down the side of the plug… not viewing from a 45 degree angle, which I see a lot. The slide magnifier box makes this a lot easier.
The right tools for the job are imperative to do the job right… period.
Attached is an example of how easy a magnifier box and some light can make a decision on what many would describe as a close call. It’s really not very close at all. Plug this all day long, and it will still be the same… just a plain 10, not an X.