Group size - what is good?

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BGC
Posts: 47
Joined: Tue Sep 09, 2008 7:24 am

Group size - what is good?

Post by BGC »

Hi all

OK, testing SB ammo... I've been doing this for some years now at the factories in Europe.

I'v been to both Lapua, RWS and have had my action at Eley. The best stuff I've found, has an average of 13,0 mm (over3 or 4 10 shot groups). And a bunch of lots about 14-15 mm in avg.

Then, I know some people who have found 11,5 mm in average. But how common is that?

You guys who compete at WC level or higher, what are your preferenses for a competetive batch/group at that level of competition? Would you go there with a 13-14 mm lot?

Just curious to find out where you draw the line. Thanks.

/ BGC
Environs
Posts: 31
Joined: Thu Nov 20, 2008 9:28 pm
Location: New Zealand (Cambridge)

Post by Environs »

Great question, I to would really like to know what level of ammo/rifle accuracy top shooters go to mathes with.
Tony C.

Post by Tony C. »

While I'm not a world class shooter, but has retired from national level rifle matches after more than 20yrs, (I now mostly shoot pistol) I think I can discuss this topic with some knowledge.

The 10 ring on a 50m small bore target is 10.4mm, so in order to ensure all shot will land inside the 10 ring disregarding shooter errors, you'll need ammo that capable to group under 10mm outside dia. or 4.5mm ctc.

Most top grade ammo when matched to a barrel should have no problem group into 11-12mm range, over 13mm aren't just not acceptable for top level competitions, however .22 ammo that capable group under 11mm just don't appear on store shelves everday, for lots of rifle shooters its a never ending quest.

If you are serious about International level competitions, before spending lots of time and money on ammo testing, be sure your rifle is capable of takeing full advantages of top grade ammo, I've seen shooters trying to match ammo to 30 yrs old rifles and expect to find a lot that will shoot under 11mm in its wore out barrels, well chances of that happening is shall we say rather slim.

Another thing I've notice, some shooter after lengthy search, finally match a lot of ammo to his/her rifle that shot amazingly well, thinking to themself " Hmm, this ammo is great, I should save it for important matches and pratice with some cheap stuff. " months and thousands of rds later, they can't understand how come the rifle no longer able to shoot good groups with the original ammo that match to it, well because the condition of the barrel has changed!

For most shooters, mid range ammo such as Lapua Center X, RWS Special Match, Eley black box, when match to rifle should be suffice, World Cup shooter, where 1st and 2nd place can be determine by 0.1 pt. require ammo capable of inside 10 everytime.

Most world class shooters I know have at least 2 barreled action with matching ammo at any one time, shoot with barrel A, when ammo ran out, swtich to B and test ammo for A, like I said, its a never ending quest.
Guest

Post by Guest »

Tony C. wrote:While I'm not a world class shooter, but has retired from national level rifle matches after more than 20yrs, (I now mostly shoot pistol) I think I can discuss this topic with some knowledge.

The 10 ring on a 50m small bore target is 10.4mm, so in order to ensure all shot will land inside the 10 ring disregarding shooter errors, you'll need ammo that capable to group under 10mm outside dia. or 4.5mm ctc..
In your 20 years did you consider that the bullet only had to break the line to be scored a ten? Therefore a centre-to-centre group of ~ 16mm (bull size 10.4 + 2x(1/2 the bullet diameter 5.5)) will hold the ten ring.
Guest

Post by Guest »

~ 21.3 outside diameter in case you wondered.
Guest

Post by Guest »

Environs wrote:Great question, I to would really like to know what level of ammo/rifle accuracy top shooters go to mathes with.
I'd think a 40 shot group of <14mm, but they will pay as much attention to the way the group forms in the test rig and the shape of the group - not just the size.

An irregular shapes group or a group that forms with shots jumping from one side of the group to the other will get binned.
Guest_66

Post by Guest_66 »

Guest: Correct me if I'm wrong, but wouldn't it be 21,6 mm (10,4 + 2x 5,6 mm).
Guest

Post by Guest »

If you want to get down to exacts...

.22 = 5.588mm

5.588 x2 + 10.4 = 21.576, but we need to break that line to count as a ten, so assuming you're shooting on electronics, which can register to 0.1mm accuracy we'll have to minus off 0.2mm for the two outside shots to break the line = 21.376 - far from needing to be sub 10mm as per the earlier info.

Another thing to throw the result slightly is that material will be lost as the bullet travels through the rifling so the bullet will eb smaller reaching the target.
Tony C.

Post by Tony C. »

Breaking the line of course will count as a 10, however if we follow your reasoning, ammo that will group @ 21mm will be acceptable.

Lets say you are shooting a match, 1st shot is a 10.1 @ 3 o'clock, next shot is a 10.0 @ 9 O'clock, both shots are 10s and within 21mm, will you use this ammo?

For most shooters, mid range ammo those group around 13-15mm are perfectly good, the difference between it and the top range are consistency, mid range ammo will shoot good to excellent groups, but will throw a fliers or 2 now and again, serious shooters pay over $1000/case so they don't need to worry about fliers, just concentrade on their shooting.

Shooting a 10.0 or 10.1 every shot are just not good enough anymore, since ISSF is now counting center shots to break ties, the original poster of this thread asked what is the selection criteria for top level competitions, IMHO, ammo grouping @ 21mm just aren't not good enough.
Guest

Post by Guest »

Tony C. wrote:Breaking the line of course will count as a 10, however if we follow your reasoning, ammo that will group @ 21mm will be acceptable.

Shooting a 10.0 or 10.1 every shot are just not good enough
that's back-tracking on your previous post to be fair, you said to be sure of landing all shots inside the tenring you needed ammo to group under 10mm. That's incorrect.

On your point above about shooting 10.0s not being good enough - I'll bet if you shoot 60 10.0s in a row you'll win more competitions than you'll lose.
Tony C.

Post by Tony C. »

Guest, whoever you are, I think you miss my first point, for a top rank shooter, him/her idealy will need ammo that will group inside the 10 ring everytime, thats under 10mm. I didn't said only shot landed inside the 10 ring count as 10.

As for shooting 60 10.0 and win matches, can you show me anyone has done that? Frankly, judging from your post, I don't think you understand the disscussion here, in fact I doubt very much you ever shot a rifle match.

Have a good day.
Spencer
Posts: 1889
Joined: Fri Feb 24, 2006 9:13 pm
Location: Sydney, Australia
Contact:

Post by Spencer »

Anonymous wrote:If you want to get down to exacts...

.22 = 5.588mm

5.588 x2 + 10.4 = 21.576, but we need to break that line to count as a ten, so assuming you're shooting on electronics, which can register to 0.1mm accuracy we'll have to minus off 0.2mm for the two outside shots to break the line = 21.376 - far from needing to be sub 10mm as per the earlier info.

Another thing to throw the result slightly is that material will be lost as the bullet travels through the rifling so the bullet will eb smaller reaching the target.
except that
1/ the targets are gauged (paper) or calculated (EST) on 5.6mm, not the projectile diameter, and
2/ a shot only has to touch, not to break the line, and
3/ calculating the outside (or shot center) groups does not have much application for ISSF events where it is the inside diameter of a group that is important. One of the advantages of systems such as Sius Ascor test system on a ballistic testing range is that the INSIDE diameter of the group is calculated for you.
Guest_66

Post by Guest_66 »

And the electronic targets also use truncation values in order to calculate the hits as in or out.
KennyB
Posts: 396
Joined: Fri Sep 17, 2010 5:32 am
Location: London, England

Post by KennyB »

Anyway, back on topic......

I'm not world class either but:
Testing from a bench or vise, I'd reject anything over 14mm.
After that it's down to testing a batch from the shoulder and seeing how predictably it performs.

I've never been lucky enough to have a batch that shot sub 13mm from a vise - one day maybe.



BTW. RWS and Lapua produce the best results for me - Eley doesn't seem to work for some reason (probably the way my barrel has been chambered).
Roodaddy600
Posts: 47
Joined: Thu Jun 24, 2010 8:15 pm

Post by Roodaddy600 »

I will guarantee no one in the world has a gun that shoots less than 10mm groups consistently. If you get consistent 12mm shoot groups you have a hammer gun. And as for people that spend over $1000 a case of ammo not having to worry about fliers, YEAH RIGHT! It happens in ammo no matter what the cost. You won't have as many and not in every lot but you will get fliers.

Shane
Roodaddy600
Posts: 47
Joined: Thu Jun 24, 2010 8:15 pm

Post by Roodaddy600 »

I will guarantee no one in the world has a gun that shoots less than 10mm groups consistently. If you get consistent 12mm shoot groups you have a hammer gun. And as for people that spend over $1000 a case of ammo not having to worry about fliers, YEAH RIGHT! It happens in ammo no matter what the cost. You won't have as many and not in every lot but you will get fliers.

Shane
Guest

Eley Test Range Records:

Post by Guest »

Eley Test Range Records:

November 2008
■Best 40 x shot consolidated group = 13,90mm by Rajmond Debevec Olympic shooter from Slovenia
Rifle: Feinwerkbau 2700
Batch Selected: 1008-04235

■Best 40 x shot consolidated score = 426,1 by Rajmond Debevec Olympic shooter from Slovenia
Rifle: Feinwerkbau 2700
Batch Selected: 1008-04235
November 2009
■Best 40 x shot consolidated score = 428,0 by Glenn Sulser, US Army Marksmanship Unit
Rifle: Anschutz 1813 with Shilen barrel
Batch Selected:
Guest_66

Post by Guest_66 »

A year ago, a friend of mine to do a CAD picture of .22 group size vs score.

Based on that, lets have a closer look at those results from Eley, and based on a 5,6 mm bullet size.

Raymonds 426,1 = 106,525 in avg
That equals a group size of 10,41 - 12,0 mm.
Middle value (4 series): 11,205 mm

Glenns 428,0 = 107,0 in avg.
That equals a group size of 8,81 -10,4 mm.
Middle value (4 series): 9,605 mm

Remember that Eley's results are both 4x10 and the total 40 overlapped. I personally think the total group size is the most important, that one really shows you if a batch is consistent.

Some more stuff:
If you have a 12,0 mm test target, that batch equals 10,6 in avg score/shot.

A 13,0 mm batch equals 10,5.

If you want to score * only (and we presume that 50% of the 10,3 goes 'in' through the electronic targets truncation calculation when hitting between 10,3 and 10,4), you need a batch that holds 15,2 mm.


Best regards from Guest_66
Guest

Post by Guest »

Tony C. wrote:Guest, whoever you are, I think you miss my first point, for a top rank shooter, him/her idealy will need ammo that will group inside the 10 ring everytime, thats under 10mm. I didn't said only shot landed inside the 10 ring count as 10.

As for shooting 60 10.0 and win matches, can you show me anyone has done that? Frankly, judging from your post, I don't think you understand the disscussion here, in fact I doubt very much you ever shot a rifle match.

Have a good day.
I didn't say anyone had shot 60 x 10.0, simply said its possible.

You DID say top ranking shooters would want ammo sub-10mm, that isn't possible, as the above results show from Eley, their record is 40 shots at 13-odd mm, never mind 60 shots.

I've shot several rifle matches this week, so think I'm in a fair position to talk about it.
Guest

50 shots at 50 meters

Post by Guest »

Some from my testing. 50 shots at 50 meters. Barrel attached in stock and in a and shot from a test reg. shot indoor.
http://kennethnielsen.blogspot.com/2010 ... tenex.html

Ken
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