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Mozella
01-21-2015, 06:09 AM
I'm certainly not new to firearms; however, I'm just now getting interested in accurate, but non competitive, shooting a bench. In this case, I'm using a Savage MKII FV .22.

Yesterday I shot a surprising 5 shot group with all five rounds in the same hole. This is definitely not my normal group size, that's for sure.

The question is, how to measure the group size, or more to the point, how to measure the size of the resulting hole.

I believe I'm supposed to measure the diameter of the hole minus the diameter of the bullet. I think the 22LR shooters use .223". Correct?

But what size is the hole? The edges are far from distinct, at least to my eye.

The picture shows the calipers set at .332 inches. Would you say that's a fair measurement, too conservative, or too generous?

https://farm8.staticflickr.com/7491/15709828554_9e2495fbb6_o.jpg (https://flic.kr/p/pWdYH1)IMG_0031-Edit (https://flic.kr/p/pWdYH1) by Mozella55 (https://www.flickr.com/people/68227080@N04/), on Flickr

Here's the work in progress with the new Boyd Barracuda stock.

https://farm8.staticflickr.com/7468/16128878370_b4b9180ac9_o.jpg (https://flic.kr/p/qzfHBQ)IMG_0023-Edit (https://flic.kr/p/qzfHBQ) by Mozella55 (https://www.flickr.com/people/68227080@N04/), on Flickr

Nor Cal Mikie
01-21-2015, 11:07 AM
Outside to outside minus the bullet diameter. 22 RF are about .220. Maybe smaller? No matter what measurement you come up with, it's a "wallet" group for sure. Good shooting.

Berger.Fan222
01-21-2015, 11:18 AM
NRA type targets definitely have holes that are easier to measure. Even printer paper has holes that are easier to measure than that.

That's clearly an excellent group, but I'd be hard pressed to say it could be measured with any degree of confidence. Since holes are pretty easy to see through a scope at 50 yards, I'd switch to a paper that makes them easier to measure. You'll save money on targets too.

cowtownup
01-21-2015, 11:19 AM
Wow... Thats great...

yobuck
01-21-2015, 11:34 AM
Certainly is an enviable group for sure.
In scoring targets for smallbore a 22 cal plug is
often used in conjunction with a flashlite type magnifying devise.
Its purpose is to determine wether a shot might be say an x or just a very good 10.
But in a case like yours it might help determine as to it actually being one hole or a ragged hole.

keeki
01-21-2015, 12:35 PM
I would call it .000". Looks like a one holer to me. Good shooting whatever you call it.lol

GaCop
01-23-2015, 11:01 AM
One fantastic group with a rim fire!

Mozella
01-24-2015, 06:27 AM
I'm experimenting with a scoring program called On Target. It's kind of quirky and crashes frequently, but it has the capability to scan a target in high resolution and then, using a mouse, put markers precisely over a series of holes. The software will then give you the group size and other statistical data, allow you to store target data, etc.

With that program I get a 0.082" group size on the five shot target shown in my original post.

The question is, can I ever come close to reproducing that five shot group again? Probably not. In fact, the chances are between slim and none, but it will be fun trying.

js223
01-24-2015, 06:59 AM
I agree that it's very difficult to get an accurate measurement on that material. Normal target paper would be better because then you'd have the black marks more defined.

Mortblanc
01-27-2015, 01:42 PM
Our scorekeepers used to go to the outside edge of the tear made as the bullet went through the paper.

Measurement was made from the most distant tear to the most distant tear, minus bullet diameter.

Fotheringill
02-23-2015, 04:07 PM
I have always had trouble with measuring on the Birchwood Casey targets.

For paper, try the heavy NRA targets or the green meanies from American Target Company OR the ARA targets with almost an oak tag finish and thickness. Measure edge to edge and subtract .221.

And please remember to shoot at a relatively clean board upon which you have stapled your target.

stomp442
02-23-2015, 05:34 PM
Why not take an average. Measure the largest point then the smallest and call it what it averages. Very good shooting.

redlabel
02-23-2015, 10:59 PM
use card stock that you get in the printer paper section and print targets off of the net or get a target stamp from Sinclair and make your own

sharpshooter
02-24-2015, 02:44 AM
Judging the scoring rings, your score could be little as 35 or as much as 40, depending on how many cut the 8 ring.

Fotheringill
02-24-2015, 12:36 PM
Can't tell diddle on the Birchwood Casey or similar. Depending on what the target is sitting on, its thickness or nothingness, angle of the round hitting the target, there is going to be either a big splat or two or none at all.