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Discussion Starter · #1 · (Edited)
PLEASE read these rules THOROUGHLY before submitting a target to this thread, especially if it is in the top 10 - pay special attention to the instructions listed below in red.

I will run the game on the HONOR SYSTEM. No targets need to be sent in or judged.
You will be measuring your own targets, using a CALIPER or OnTarget Software. Please, no rulers.
IF YOU THINK YOUR TARGET IS IN THE TOP 10, It MUST be measured by one of our Volunteer Target Meisters- details below.

It is up to you to follow the rules.
If you think someone has measured improperly, PM ME- do not call out members in open forum. I will deal with any disputes discretely and as fairly as I can.

The leaderboard will also feature each shooters average group size, listed by rank. Please remember that THIS IS A GAME, I'm only including groups sizes so we can all see what's possible and how we stack up. That way members who want to should FEEL FREE to shoot the challenge AGAIN with the same rifle or with more than one rig and improve their score. I will be glad to update your score- please REMEMBER to send me a PM when you post a target to notify me of your accomplishment so I can update the leader board accordingly.




RULES

Rifle---Any form of 10-22 or variant thereof

Optics---Anything from Irons to Scopes

Ammo---Anything you are willing to spend money on

Rests---Two Piece rests, Bipods, Bags. No one piece or return to battery rests.

Posting Targets:

Post a CLEAR picture of your target INCLUDING 3- and 4- GROUP AVG WRITTEN LEGIBLY ON THE TARGET, and send me a PM with a link to the post to notify me of the entry.



TAKE A PIC OF YOUR RIFLE ON THE REST/BIPOD/BAGS THAT YOU SHOT FROM.

SCORING-

SIZERS-Shoot four sizers ON your submitted target. Measure them and calculate the average. Write the average clearly on your submitted target.

GROUPS- Shoot FOUR GROUPS, FIVE SHOTS per GROUP . Measure them at the widest point and write the Raw group size next to each. Subtract your average sizer measurement from the raw group size to get your FINAL group size. Write it next to each group.

CALCULATE THE AVERAGE GROUP SIZE FOR YOUR BEST THREE GROUPS AND ALL FOUR GROUPS AND WRITE THEM ON THE TARGET OR INCLUDE THEM IN YOUR POST

THREE OUT OF FOUR OF YOUR 5 SHOT GROUPS MUST BE UNDER .500" TO MAKE THE LIST



ALL TARGETS THAT ARE IN THE TOP 10 NEED TO BE MEASURED USING ONTarget SOFTWARE BY THE SHOOTER OR ONE OF OUR RESIDENT TARGET MEISTERS LISTED BELOW.

IF YOU HAVE MEASURED YOUR TARGET AND THINK YOU'RE IN THE TOP TEN, SUBMIT THE TARGET FOR MEASUREMENT TO ONE OF THE TARGET MEISTERS.

***YOUR FINAL SCORE WILL BE AVERAGE OF YOUR MEASUREMENTS AND THE OnTarget RESULT OF THE TM.

PLEASE follow the instructions below when sending a scanned copy or JPEG of your target to the Target Meisters.

If your target does make the top 10, please send it to me in a PM and post it in this thread with your caliper or On Target measurements including three - and four - group averages.


Please remember these are neutral third-party volunteers who give their time freely and be patient with them while they measure.

When sending targets to the Target Meisters for measurement please;

1. Send the targets by email not by PM. Email address should be in our profiles.
2. Include either a scan of the target or a .jpg file of the target. The same .jpg used to upload to photobucket or whatever service is used.

This makes it much easier for us to measure and then return the results to the shooter.

TARGETS: ALL TARGETS FOR THE GAMES MUST BE SHOT ON ONE OF THE FOUR TARGETS IN THE FREE DOWNLOAD LINKS BELOW. ABSOLUTELY NO EXCEPTIONS WILL BE MADE!!!

Username= DrGunner Password= RFCtarget



TARGETS FOR THE MOA GAMES: 1/4" at 25 Yards, 1/2" at 50 yards, and Holy Grail- 1" at 100 Yards


Stealth's 22 Challenge Has 4 boxes with crosshair and red bullseye, as well as four separate boxes for sizing shots, with data underneath. This target is used for MOA games and shooting groups, created by member Stealth01- my gratitude to him!

TARGET DOWNLOAD LINK:

LINK: http://www.keepandshare.com/doc/5216164/sent-to-myself-201

Username= DrGunner

Password= RFCtarget


Below is a SAMPLE ONLY, follow the link above to DOWNLOAD the PDF for the OFFICIAL SIZED TARGET :



Target with Data, supplied by VINCENT created by member Komi Has 4 crosshair targets with 3/8" white bullseye, as well as four separate small crosshair targets for sizing shots, with data underneath. This target is used for MOA games and shooting groups.
It is my favorite for the 1/4" and 1/2" MOA games, due to its simplicity.

TARGET DOWNLOAD LINK:

LINK: http://www.keepandshare.com/doc/5198082/sent-to-myself-201

Username= DrGunner

Password= RFCtarget


Below is a SAMPLE ONLY, follow the link above to DOWNLOAD the PDF for the OFFICIAL SIZED TARGET :



OnTarget with Data, Thin Crosshairs: created by TargetMeister Bill40718, with standardized measurements specifically designed for accurate measurement of 5 shot groups using OnTarget. This thin crosshair version works best for 25- and 50 yards. The stepped crosshairs on the horizontal and vertical serve as aim points for shooting groups in a quadrant, allowing for clean measurement away from the bullseye.

TARGET DOWNLOAD LINK

LINK:http://www.keepandshare.com/doc/674...sshairs-ricochet-modified-thin-crosshairs-pdf

Username= DrGunner

Password= RFCtarget


Below is a SAMPLE ONLY, follow the link above to DOWNLOAD the PDF for the OFFICIAL SIZED TARGET :



OnTarget with Data, Thick Crosshairs:OnTarget with Data, Thin Crosshairs:[/COLOR][/SIZE] created by TargetMeister Bill40718, with standardized measurements specifically designed for accurate measurement of 5 shot groups using OnTarget. This thick crosshair version works best for 100 yards. The stepped crosshairs on the horizontal and vertical lines serve as aim points for shooting groups in a quadrant, allowing for clean measurement away from the bullseye.

TARGET DOWNLOAD LINK

LINK:http://www.keepandshare.com/doc/674...shairs-ricochet-modified-thick-crosshairs-pdf

Username= DrGunner

Password= RFCtarget


Below is a SAMPLE ONLY, follow the link above to DOWNLOAD the PDF for the OFFICIAL SIZED TARGET :



Click on these usernames to link to our Target Meisters profiles to send a Target via PM, or email them directly:



Click HERE to link to TargetMeister Jesse aka Slimjd33's Member Profile

Slimjd33's email: [email protected]

Click HERE to link to TargetMeister Kent aka rokehe's Member Profile
rokehe's email: [email protected]

Click HERE to link to TargetMeister Elijah aka layer3guru's Member Profile

layer3guru's email: [email protected]

Click HERE to link to TargetMeister Dave aka 10ring1's Member Profile

10ring1's email: [email protected] [/SIZE]






MEASURING GROUPS, SIZERS & RAW vs FINAL GROUPS

Measuring Groups

The raw group size is the overall size of the group measured from outside edge to outside edge. What I have found to be the best and most consistent way to measure a raw group is to measure the outside edge of the bullet smudge on the paper from the widest point of the group using a caliper, placing the group deep within the flat part of the jaws of the caliper.
Sizers are used to calculate the final group size. What you're doing essentially is subtracting the size of one bullet with from the raw group size in order to end up with a final group size, Which reflects the center of POI for the two bullets that are farthest apart in the group. In order to calculate an average sizer, you shoot four separate sizers on a different area of the target from your groups. Measure the sizers in the same fashion as the groups - outside edge of the smudge outside edge of the smudge. Most sizers are around .210 - .215 inch.
Add up the four measured sizers and divide by four to get an average. Then you subtract that value from each of the raw group sizes to get a final group size for each of your groups. Just remember that the smudge represents the outer edge of the contact area of the actual bullet, and we are trying to calculate the group size from point of impact to point of impact. Subtracting a sizer results in removing 50% of the average width of a bullet from each side of the widest part of the groups, giving you the center of POI for the widest part of the group.

Because ammo and paper varies in the marks left on paper, doing it this way ensures that we are taking into account the way that your particular combination of rifle/ammo/paper is factored in by using your sizers. Because we are measuring the smudge, shooting a few fouling shots in order to dirty the bore helps a lot because subsequent bullets will print a better/more distinct mark on paper that is easier to read and see.

One good practice to help you understand why we are measuring the outside edge of the smudge is to plug a target - In particular, a sizer. Take a live unfired round and push it slowly into a sizer hole up to the base of the bullet just before it contacts the casing. You will see that the width of the hole made by the bullet is actually larger than you would expect based on the hole in the paper. The smudge left behind by the passing bullet provides a reasonably accurate estimation of the actual size of the hole, especially when averaged across four separate sizers.

MEASURING SOFTWARE

Use of computer-generated measuring software such as OnTarget is encouraged. I do request, however that you post two copies of your target, one with the digitally rendered measuring data and bullet circles and one in it's digitally unaltered/pure form so that we can look at the target without the electronically generated clutter.
I also ask that you type out the group sizes, sizer average, and average of three - and four - groups in your post because reading them off of the computer generated images is sometimes very difficult.

PLEASE remember we are here to have fun and challenge ourselves.

LET THE GAMES BEGIN!!!

DrGunner
 

· Administrator & Consigliere
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Discussion Starter · #2 · (Edited)
The club

LEADER BOARD

MEMBER --AVG (3 groups)---AVG (4 group)---Rifle

jcrowleyiv-----------.150--------------.170------------"Legacy"- Ruger/ CPC GM Octagon. CLICK to LINK to the TARGET

DrGunner------------.156-------------.186-------------Eliminator/Kidd/Lilja. CLICK to LINK to the TARGET

DrGunner-----------.158--------------.169-------------Raptor/Ruger/Kidd LW. CLICK to LINK to the TARGET

jcrowleyiv-----------.164--------------.175-------------Mannlicher

Billysue--------------.165--------------.189-------------Wile Coyote

Bill40718------------.173--------------.202-------------"Somethin' Else"

Les1911--------------.186-------------.211--------------"GM 25"

MtStream------------.194--------------.205--------------B&C/Kidd

Fullup 3-------.210------.293-------20" Kidd

Les1911--------------.220--------------.263-------------Kidd/Terminator

Smoothtrigger-------.221--------------.226-------------Kidd Supergrade

layer3guru-----------.226-------------.291---------------Tactical Innovations/Kidd

lilski------------------.227-------------.307---------------Lilski BR

Midwest Swiss-------.228-------------.249--------------Douglas

popcornkid-----------.230-------------.298--------------Clark Custom

Dr Heckel------------.232--------------.282--------------Eliminator/Kidd

rokehe----------------.232-------------.288--------------"Groovie 3.0"

dhuze----------------.237--------------.347-------------"Auction Improved"

Billysue--------------.243---------------.260------------"Chef Logan"

Les1911--------------.243-------------.281-------------"Fred Ruger"

Midwest Swiss-------.247-------------.271--------------"Snake"

Ron1738-------------.247--------------.309-------------Kidd/Feddersen

Dr Heckel------------.252--------------.306-------------McMillan/Kidd SG

JDouglas--------------.261-------------.357-------------Kidd/ T-Rex

Billysue---------------.261-------------.284-------------"Sam Brady"

Billysue---------------.264-------------.290-------------"Dan Boone"

CBF Gettysburg------.264--------------.295------------"Kidd Stuff"

rokehe---------------.265-------------.350--------------"Bionic" LVT

recon31--------------.268--------------.318-------------Ruger/Feddersen

MasterZerak----------.278--------------.283-------------Kidd Supergrade

seandradamus-------.279--------------.297-------------Tacticool/Kidd

Clem-E---------------.280------------.327---------------"Pugsley"- Ruger/Kidd

4mula--------.281------.346-------"Bourne Ultimate"

Tom E Gun-----------.281-------------.371--------------Dlask/Kidd

vettepicking----------.283--------------.328------------"Pure Lightning"

martinigallery--------.284--------------.337------------"Plinker"

MtnBiker6510--------.286--------------.305------------"Charlie"

lilski-------------------.292------------.298---------------"lilski 3G"

MG427----------------.295-------------.387-------------Kidd

Hawkeye57----------.296--------------.422-------------"Old Brown Shoe"

Ron 1738-------------.297-------------.343-------------Kidd/Feddersen

rokehe----------------.299-------------.363------------"Pennywise"

dhuze-----------------.300-------------.392-----------"Auction Mistake"

Bucketman-----------.300--------------.415------------"Purple Haze"

Green River-----------.303-------------.339-------------Kidd 10-22

CBF Gettysburg------.303--------------.390------------Feddersen Contour

Nosnil22--------------.310-------------.336-------------Nosnil BR50/Shaw

Bill40718--------------.310-------------.353-------------"Crown Vic BR"

JacobPendergrass----.315-------------.359--------------K10-22T

SavageManM2--------.315-------------.436--------------Ruger/GM Running Boar

1Corinthians2---------.319-------------.374-------------Cedar 10-22

Blacknboostn---------.322-------------.439---------------GM/Tacticool

copterdrvr------------.324-------------.362---------------Kidd/Vantage

rawhp-----------------.328-------------.358--------------"Ugly Duck II"

gunfan2--------------.330--------------.356--------------"Bess" VQ Custom

copterdrvr------------.332-------------.368---------------Feddersen

jgraves---------------.333--------------.390--------------Kidd SR22

Clem-E----------------.335-------------.384--------------"Mr. Clark"

ScottNC----------------.336------------.362---------------Kidd/Vantage

Magwa-----------------.336-------------.426---------------"Slick 50"

brandnew1022--------.344--------------.376--------------Ruger/Kidd 20"

jcrowleyiv-------------.345--------------.352--------------Gatewood T-Hole

SWIGIN---------------.345-------------.380----------------Ruger/Kidd

martinigallery--------.345--------------.459----------------"Wasp"

J31868---------------.347--------------.388----------------GT-22

philoshop-------------.351-------------.388----------------Kidd Tacticool

CBF Gettysburg------.352--------------.441---------------Kidd 16.5 LW

Kapenagary----------.354--------------.494---------------Kidd

martinigallery---------.365--------------.446--------------"Heavy"

grovedesign----------.368-------------.439---------------Maple BR/Ruger/Kidd

recon31--------------.370-------------.400----------------Ruger 10-22T SS

t0pcat----------------.372-------------.403---------------Kidd 10-22

Mjaynes7-------------.378-------------.401--------------"Calamity Jane"

dvrein----------------.379-------------.397----------------"Red Glitter" GM

CBF Gettysburg------.386-------------.460---------------"Joe Black"

Larry_M---------------.391-------------.418---------------"Patience"

rokehe----------------.409-------------.428---------------"Maximus"

GBLEV173-------------.424-------------.466---------------Kidd/ Leo Bourne

JDouglas---------------.465------------.524-----------------Axiom GM

*************************

Member lilski was generous and industrious enough to put together the following spreadsheet listing the build specifications and other relevant data for the top scoring rifles. THANKS lilski!!!!!:bthumb:

 

· Administrator & Consigliere
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Discussion Starter · #6 ·
Oh, I TRIED to top that amazing feat by MtStream, but couldn't get it done. Not sure if I can.....
I tried Lapua Center X, Midas +, Eley Black and Team during 3 different range sessions, all with halfway decent conditions.
Shot a .2678, .2410, .2403 and several others between those and .5000. Was at it most of the day today.
Not done trying yet, but I'm going to give this a break for a few weeks and go fishing:bthumb:.
I'm waiting for you to post a target...
DrGunner.
 

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Discussion Starter · #10 ·
Hey Larry-
Glad to see you joined in. I know you can shoot better as evidenced by your performance in the Tack driver thread. I have had really good luck with Eley Team and Lapua Center X lately....

DrGunner
 

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Discussion Starter · #13 ·
Hey Doc-
I will take it, since all the groups on paper are under 1/2". Although for future reference you should shoot your four sizing shots ON the same target.
Also, please post a pic of your rifle on the rest you used if you have it. If not, take one and edit it into your post next range trip.
Very nice shooting, sir!

You might want to check out the other games:

Tack driver 25, 50, and 100 yards:

For a really tough challenge, try the 25 yard tackdriver target from 50...

http://www.rimfirecentral.com/forums/showthread.php?t=462689&page=2

1/4" at 25 yards:

http://www.rimfirecentral.com/forums/showthread.php?t=462790

And last, the "MOA Holy Grail", which I just completed myself with two of my rifles on Wednesday:

http://www.rimfirecentral.com/forums/showthread.php?t=462806

Good Luck & Congrats!!!

DrGunner
 

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Discussion Starter · #17 ·
Great shootin' Doc:bthumb: I need to get back to working on these targets and get my name on the top of the list;) I'll be happy with top 3:D

All the KIDD hype is true huh!?
Yeah- I have 4 10-22s, and this is my first Kidd barrel. I shot Wolf MT for the first 100, then switched to CCI SV. It shoots better than the GM and WP on day one.
It actually likes Federal Automatch, which is good because I have about 1/2 a case of it as I usually use it for plinking ammo in my S&W 422 and Browning Buckmark.
I'm looking forward to shooting the 20" SG.

DrGunner
 

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Discussion Starter · #22 ·
Shot prone with a Harris bipod and rear bag. I didn't have a camera at the range so I posed the rifle in my office. This was my third attempt at the 50 yard target. I made the average on one of the earlier targets but only had 2 groups under 0.500".

Jeff
Congratulations!!! Nice shooting for a bipod! You have the honor of being the first with a tactical build to make this, as far as I know.
I've never shot Lapua Pistol ammo before. I had considered it...
Is it consistent? Price?

Welcome to the club.

DrGunner
 

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Discussion Starter · #25 ·
Thanks. I built the rifle to be easily transportable in my Miata and as a trainer for Canadian service rifle competition only to conclude I already have too many hobbies. I don't think the bipod is much of a hindrance but the M4 style collapsible butt stock is about the worst I could image on a rear bag.

I purchased 2 boxes of practically every 22LR cartridge SK and Lapua sells, trying to find MOA from this rifle. The Pistol OSP is the same cost as Center-X and only marginally better than SK Rifle Match, based on the single batch testing I've done.

I haven't made up my mind yet but I think I'm going to a 3 tier ammo strategy, CCI Std Vel for plinking and handgun practice, SK Pistol Match Spezial for bullseye competition and serious off hand rifle practice and Center-X for any supported (including sling) rifle shooting.
The three tier strategy you mentioned is pretty much how I sort things out. CCI SV and Federal Automatch for plinking and practice. Wolf MT or SKRM for 25-50, and Lapua Center X or Midas+, or Eley Club and Team for serious target work. I have one rifle that favors the Lapua line but shoots SK better than Wolf, both Standard vs MT and RM vs ME. I have another thats becoming an Eley snob. If i could afford to, i would shoot nothing but Eley Tenex and Lapua Xact.

I am definitely going to give Lapua OSP and Eley OSP a try.

Some fantastic shooting. I can get 4 shots in a ragged hole, then, always a flier. I don't care what rifle I'm shooting and what ammo. It usually takes about 20 to 30 shots to get things to settle down, then I shoot some good groups, most in the 3/4 group range, every once in a while a very tight group, but always the flier. If I ever shoot a 5 shot one hole group I will post it, but to date it eludes me. I shoot 90% of my targets at 100yds. my Magnum Research, with the Kidd trigger and bolt, I shoot at 50yds...Tom
I have really worked hard on this. I used to think that shooting groups at 25 yards was a waste of time. Not anymore. It builds confidence for me, and helped me considerably in tuning my technique by reducing the influence of variables such as bullet drop and wind. After I could shoot bug holes at 25, I moved to 50 and worked even harder. I used to shoot 50 and 100, just like you.... Moving to 25 forced me to unlearn certain bad habits that I had developed over 35 years of shooting. What I do is to first test a rifle locked into a one piece rest, with hydraulic trigger pull to take myself out of the equation. I test many brands of ammo, several flavors of each. I'm not looking for the .0XX, but trends. When I find the ammo that the rifle likes, then it's a matter of testing different lots to find what works best.
After I'm done testing, tweaking and tuning the rifle, the test bench goes back in the shed and the real work begins- seeing if I can even come close to reproducing groups in the neighborhood of the test.
It often takes me 10-20 rounds to get things working, then I shoot a few groups and go back to my sight in target, and repeat until its time to run the boresnake.
The targets I've posted in these games ARE cherry picked. For every one posted there were dozens before...



DrGunner
 

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Discussion Starter · #27 ·
DrGunner: I don't have access to a one piece rest, but, I will move back to the 25 yrd bench, use my sand bags and see what happens. Thanks for your advise...Tom
Watch Cabelas, I bought this Hyskor on sale for $40:



Mine is bolted to that cabinet, with wheels on one side and a pair of shovel handles to move it wheelbarrow style. Might not be worth the investment for everyone, but it does a great job of testing what the rifle alone is capable of.

DrG
 

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Discussion Starter · #28 ·
Reposting now that I have a pic of the Archangel with the Kidd LW:

Promag Archangel Deluxe Target stock, Pillar & Devcon bedded
Morgan adjustable butt pad
Kidd receiver pins & bolt buffer
Kidd Classic Rcvr w rear tang
Kidd Lt wt 18" .920 barrel
Kidd silver scalloped bolt
Kidd charging rod & spring
Kidd single stage triggerset @ .87#+ custom skullie mag release by Chaser
Scope: Mueller 8-32x40 Side Focus Target scope on Leupold QRW low rings




DrGunner
 

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Discussion Starter · #31 ·
Here is my entry, measured with OnTarget.



If you can't read the numbers the groups measure, from top left going clockwise, .335, .471, .259 & .437.

and the rifle...



Not allowed to take pictures at this range so I staged it at home.

It's a Kidd 20" bull with a Que'd bolt and VQ trigger kit in a carbine stock that I modded to fit me.

Ammo is SK Standard plus and the optic is a Simmons Whitetail Classic 6.5x20-50.
Nice shooting- I'm assuming you have long arms...
I added adjustable butt plates to 4 of my rifles for the same reason.
Welcome to the club!!!

DrGunner
 

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Discussion Starter · #33 · (Edited)
I would like to express a special thanks to Stealth01 for the great work he did for the games and all the members that use the targets from them. First he took the time to modify the original Sharpshooter target to include all the necessary data entry blanks and he improved the actual target boxes and bullseyes.

Then he designed an all new target, which I named "Stealth's 22 Challenge." I used it to dial in an air rifle yesterday and believe it will be the best target we have for shooting at 25 and 50 yards.

He asked if I wanted anything amended.... I asked for larger bullseyes-
1" in diameter for shooting at 100 yards. Instead of an amended target, he designed and created another one that has been dubbed "The Holy Grail", with nice big red bullseyes to help set off the crosshairs at distance, all data slots, nice sighter boxes and a layout that places the groups as far away from each other as possible.

Finally a target where we don't have to worry about a sighter wandering into one of the herds!!!!

THANK YOU! STEALTH!!! for your time and contribution to the forum.

Here are the links:

They are PDF downloads on a KeepandShare account. If you are asked for a username and password, they are:

Username= DrGunner Password= RFCtarget

Stealth's 22 Challenge created by member Stealth01- my gratitude to him!

http://www.keepandshare.com/doc/5216164/sent-to-myself-201

Sharpshooter Plus Data Modified by member Stealth01

http://www.keepandshare.com/doc/5190240/sent-to-myself-201

Stealth's MOA Holy Grail Created by member Stealth01

http://www.keepandshare.com/doc/5216161/sent-to-myself-201

Stealths MOA Holy Grail Bicolor Created by member Stealth01

http://www.keepandshare.com/doc/5246584/sent-to-myself-201

Target with Data, supplied by VINCENT Created by Komi

http://www.keepandshare.com/doc/5198082/sent-to-myself-201

Enjoy!!!!

DrGunner
 

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Discussion Starter · #36 · (Edited)
Measuring groups

Over the past couple of months, many members have sent me PMs and emails asking questions about the proper way to measure targets. I thought I would post this here and hopefully simplify some things although I might make it worse...

The raw group size is the overall size of the group measured from outside edge to outside edge. What I have found to be the best and most consistent way to measure a raw group is to measure the outside edge of the bullet smudge on the paper from the widest point of the group using a caliper, placing the group deep within the flat part of the jaws of the caliper.
Sizers are used to calculate the final group size. What you're doing essentially is subtracting the size of one bullet with from the raw group size in order to end up with a final group size, Which reflects the center of POI for the two bullets that are farthest apart in the group. In order to calculate an average sizer, you shoot four separate sizers on a different area of the target from your groups. Measure the sizers in the same fashion as the groups - outside edge of the smudge outside edge of the smudge. Most sizers are around .210 - .215 inch, with some ammo printing larger and smaller than this average which is just an observation of mine.
Add up the four measured sizers and divide by four to get an average. Then you subtract that value from each of the raw group sizes to get a final group size for each of your groups. Just remember that the smudge represents the outer edge of the contact area of the actual bullet, and we are trying to calculate the group size from point of impact to point of impact. Subtracting a sizer results in removing 50% of the average width of a bullet from each side of the widest part of the groups, giving you the center of POI for the widest part of the group.

Because ammo and paper varies in the marks left on paper, doing it this way ensures that we are taking into account the way that your particular combination of rifle/ammo/paper is factored in by using your sizers. Because we are measuring the smudge, shooting a few fouling shots in order to dirty the bore helps a lot because subsequent bullets will print a better/more distinct mark on paper that is easier to read and see.

One good practice to help you understand why we are measuring the outside edge of the smudge is to plug a target - In particular, a sizer. Take a live unfired round and push it slowly into a sizer hole up to the base of the bullet just before it contacts the casing. You will see that the width of the hole made by the bullet is actually larger than you would expect based on the hole in the paper. The smudge left behind by the passing bullet provides a reasonably accurate estimation of the actual size of the hole, especially when averaged across four separate sizers.

In the games, you would then calculate the average of all four final groups on a target as well as an average of the best three groups on the target.

Hope this helps!
Feel free to PM or email me with any questions

DrGunner
 
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