Does measuring group size on the back side of the paper, center to center make sense to anyone else? Because in this case the holes are much smaller and easier to see than from the front. Of course if the 2 outside bullet holes touch then it's harder. But if the don't...thoughts?
Measuring Groups on back side of paper?
- Thread starter CA_Shooter
- Start date
I suggest measuring on the front of the target outside edge to outside edge and subtract the size of the bullet.
Heavier weight paper will cut better holes. I measure from the front.
Paul
Paul
I use Imperial sizing wax. Even though I use it very lightly and I wipe off the cases after sizing, the holes have a gray discoloration that could come from the wax. More likely it is carbon residue from inside the case necks. I almost never tumble my cases. I just wipe them off after sizing and I run a brush inside the case necks.
When a hole has tears, when I flatten it out I can see exactly where the bullet hit from the grey discoloration.
When a hole has tears, when I flatten it out I can see exactly where the bullet hit from the grey discoloration.
Last edited:
jepp2
Gold $$ Contributor
I flatten then tape. Then I use OnTarget software. Just center the circle for the caliber you are shooting. It just makes life easy.
therifler
Silver $$ Contributor
front side outside to outside subtract bullet dia . as said here .
jimmymac
Jim McGregor
Measure any way that makes the group smaller. D
garandman
Bolt Gun Bodacious
I shoot 1- shot groups and rarely end up with a group larger than the bullet diameter. If I do my part.
I probably need to start using better paper because the imprint of the bullet on the paper isn't as big as the bullet diameter. Therefore, using the method of measuring outside to outside makes my groups seem smaller than they actually are.
dellet
Gold $$ Contributor
That's not uncommon and the marks should be consistent in size.
Measure outside to outside, and subtract the diameter of the mark instead of the bullet. Example a 30 caliber might leave a .295 mark.
Yep, better paper helps. I use something called card stock, and I print my own targets on that.
DaveTooley
Gold $$ Contributor
TARGET MEASURING
Neil Jones Custom Products - Accuracy tools and components for the precision shooter
www.neiljones.com
The IBS record committee has used something similar for decades. Three different people can measure the same target and very seldom differ by more than a few thousandths so something must be working correctly.
Ned Ludd
Silver $$ Contributor
FWIW - a friend showed me a few years back that the cardboard from regular brown boxes seems to allow the bullet to cut a much sharper hole that it would in typical printer paper. I always have some boxes lying around, so I started cutting them up for use as targets, and the edges of the bullet holes really are much sharper than with printer paper, unless you buy specialty heavyweight stock.
Because the bullet holes are usually smaller than bullet diameter as you noted, measuring bullet hole/group dimensions center-to-center is the better method. Further, software such as OnTarget that measures groups center-to-center is readily available, often for free if you choose an earlier version.
Because the bullet holes are usually smaller than bullet diameter as you noted, measuring bullet hole/group dimensions center-to-center is the better method. Further, software such as OnTarget that measures groups center-to-center is readily available, often for free if you choose an earlier version.
CaptainMal
Silver $$ Contributor
I use one of those Neil Jones tools to measure both club and IBS targets at Manatee. I put that tool under a large magnifying glass and center holes of different bore sizes around one hole in the target. Then there is a straight line in that plastic line of hole sizes. If you place it in the center of the far hole you are measuring to then move the proper size hole to go around that far hole, the readout is within a couple thousandths.
Hard to describe above but simple if you have the tool in your hand. Measing with a plain caliper is tough as there is often bullet yah and the holes may not be round, finding center is still a guess and there can be paper issues. Edge to edge or center to center is fine for casual measurements. To do it right takes that Neil Jones tool or the like.
Hard to describe above but simple if you have the tool in your hand. Measing with a plain caliper is tough as there is often bullet yah and the holes may not be round, finding center is still a guess and there can be paper issues. Edge to edge or center to center is fine for casual measurements. To do it right takes that Neil Jones tool or the like.
Much easier to measure the groups on heavy card stock paper because the holes seem to be more uniform in the thicker paper and the bullet don't tear long splits.
Here are a couple of photos showing the grey marks on the target which I believe are coming from carbon residue, but some sizing wax is also a possibility. The photos are after flattening out the tears from the back side of the target and placing a piece of tape on them to hold them flat. The grey circles are very close to the same diameter as the bullet caliber.
Attachments
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.