View Full Version : Reading Group Shape

11-24-2010, 05:59 PM
Can experienced BR shooters tell anything or make a judgement about a load or shooting habit from observing a target group ? I have pics of two 110-yard targets I shot last week, both show the same pattern. Trying to see if there is more than meets the eye. Thanks !!

11-24-2010, 06:27 PM
A picture or two would help, it is almost impossible to diagnose a problem without looking at it or having a very detailed description. What kind of rifle; hunting, varmint or benchrest; what kind of bench; what caliber; what kind of rest; etc.

11-24-2010, 06:50 PM
6.5-06 46.8 gr H4831 142 SMK bullets - Original 1912 stock and action, Modelo Chileno Steyr Austria (Model 98 Mauser) 27-inch Douglas Heavy Contour hunting barrel, off bags at 100 yards, some wind estimate 10-15 mph right to left. The load is very light. I hogged the stock out to accommodate the heavy barrel. I surprised myself when I was sitting around and measured the spacing with a caliper. I am trying to see where or what to do next to get er down to size. My stated goal when I joined this BB back in March was to shoot with my son and hit a Gong at 1,000 yards. I figure, other than scope elevation problems, I need a small group at 100 yds, then worry about further out. Tasco 6-24 scope in a 1-piece Redfiled mount btw. The more I learn the more stuck in the $quagmire$ I get. This round was virgin Remington 25-06 brass one lubed pass through the RCBS fullsize die, then trimmed and neck neck sized with the Lee custon Collet die and bullet seater. I have seen cautious individuals hesitant to post for being flamed, not here for that. If I can't get a good answer here, then it's just random BS from well meaning range folks...... Here are the pics....... There's five shots in each group. Two holes of two shots, and a third. Both times. Thanks in advance.



11-24-2010, 07:55 PM
Two 5-shot groups are not going to tell you much--nothing, really. You would have to shoot many more groups to see if your rifle consistently produces a predictable pattern of where the bullets land within each group.

One thing that might reveal some information is to number each shot as it appears on the target. Then, by comparing many groups you can detect patterns if they actually occur.

11-24-2010, 08:20 PM
Never considered that. Thank you. I am getting a record book to record everything I do from now on. Pulled the chrono with battery thats been in a box since 2001. Flicked on and it's still good to go. Take what, minimum 4 groups of five ?? I am still relearning and developing a load.

11-24-2010, 09:11 PM
If your intentions are to shoot out to 1000 yards, skip the 100 yard load development and move out to 300 yards. ;)

11-24-2010, 09:48 PM
Thanks AJ. Range is limited to 200 yards. The longs range is across town, with 1,000 and F-class matches. What will I get at 2x the distance that I cant get at 100 yards ? I am still developing the load. The xtra walking will give the barrel more time to cool off. You're saying the spread in the group will open up and show more. So, I will have more obvious spread to look at and can tune the load better (?) Novice merciful thanks !!!

The Quagmire I refer to is that if I need 20 shots to show a pattern that is repeatable, and I try only 5 variables, thats 100 shots right there. You guys shoot a boat load, huh ? I'll replicate that load, and a little more powder, and little more length, and try at 200 yards on Sunday. Thanks Again.

11-24-2010, 10:23 PM
What will I get at 2x the distance that I cant get at 100 yards ? I am still developing the load. You might be surprised. If things begin to open up quickly at 200, then you've got velocity issues that you really won't be able to see at 100. He's recommending 300 cause that's a little better yet, but still easily able to go on an 8-1/2x11 sheet.

You're saying the spread in the group will open up and show more. So, I will have more obvious spread to look at and can tune the load better (?) Pretty much, yes.

You guys shoot a boat load, huh ?Yep.

I'd begin by finding the powder that's best for your combination. I find it hard to imagine that 4831 is that powder. Probably something faster is going to work out better, but I could be mistaken. If you have a chronograph, get that involved and make sure you have velocity for the 1000 yard trip.

The group you have above is not gonna win a BR match, but, I'd bet you'll make hits on that gong without any problem. Maybe not every shot, (might not even every other), but you'll hit it. THe biggest issue you're up against is velocity. If you don't have enough to send the bullet 1000 yards, then all the short range accuracy in the world won't help. You've probably got to get those 142's up around 2850 or greater (minimum) to do what you intend. But, I'd head to the range and try it at 1K just for the fun of it! Nothing ventured nothing gained.

11-24-2010, 11:10 PM
Yeah, the velocity is marginal. I only have published data to go off of for part of this adventure. Sierra's charts show the 140 SMK (not the 142, my manual is circa 1996) still supersonic at 1K with a muzzle of only 2400 fps. My light load may only be just beyond that. Doesn't mean it will stay nice and tight at that speed, right ?? I think I see the logic now.. .. My old load with the 140 gr hunting spitzer from 1999 or so was at 2880 or so, by chrono. But that was 51.5 grains powder. That load never shot this well. Sierra shows slower powders for velocity and accuracy for what was a wildcat. Their accuracy load is VN160 at 2850 fps, full max for that combo, and velocity with H4350 at 2950, full max do not exceed. The H4831 is within a lick of that in the good book, 50 fps. Too much to learn too fast. What the $%# are these guys doing loading this to a claimed 3200 fps ?? My original load did shoot my first deer. Looks like I'm gonna need a lot more brass and bullets to play with. Thanks for the suggestions.

Charles E
11-24-2010, 11:19 PM
I don't often disagree with 4Mesh, but it does happen. I use to shoot a 6.5/06 Ackley Improved, which is about 4 grains more capacity than your plain 6.5/06. H4831 is a good powder. Rel-22 worked better for me, but there were a few people who got better accuracy with 4831 (Larry Jones, for one, Phil. Both Joel and I shot Rel-22, and for a year, we'd trade off who won group, who won score. And yes, this was with the 142 SMK. Bit stiffer charge than he's using, though.)

One downside of Rel-22 is it's burn rate varies a fair bit from lot to lot. You have to test each new lot. There are years when the whole line of Reloader powders seems fast, years when it seems slow. In the very fast years, you can usually go to Rel-25, in the slow years, Rel-22.

It's rumored that Norma MRP is held more tightly lot to lot. Maybe, but both the Norma and Reloader double-based rifle powders are made by Bofors. That would be a bulk powder, which can vary by 20% in burn rate. Norma and Alliant repackage it and sell it as canister grade; canister-grade powders are suppose to be held to 10% variation. It often seems like Alliant (Reloader) uses all of that. Perhaps Norma controls things better, I do not know.

I go on at length about Rel-22 because so many have found it just about right for the 6.5/06AI.

* * *

About testing at 100 yards: You can, but you have to be able to trust your shooting. Is 3/4 of a bullet hole worth of vertical caused by velocity variations, or less than "quite good" shooting on your part?

I do most of my load development at 100 yards. If there is a bullet hole or so of vertical, I'll still use the load, but make a mental note. If I'm getting vertical at 1,000, I know where to look.

* * *

Statistically, it takes about 10 five-shot groups to be significant. I've seen it argued that to get reasonable Standard Deviation numbers, you need around 70 shots.

Well, that's too many rounds on a barrel.

The usual load development procedure for an experienced BR shooter is to shoot 3-shot groups, where the purpose is ruling things out. If three shots are bad, the fourth and fifth aren't going to make the group any better. Again, you have to trust your shooting. Once you get a powder/bullet combination that isn't bad, it is time to start the 5- or 10-shot groups.

Another thing to remember is Benchrest competitors -- particularly 1,0000 yard BR -- are going to test several powder and bullet combinations with each barrel. Short range benchrest is primarily the 6 PPC for group, or .30 BR for score. Most everybody shoots a rifle of the same weight, with a barrel of the same length, etc. Most of us stick with one powder, and maybe several types of bullets.

This is less true with the 1K stuff. In other words, along with the 142 SMK, I'd at least include trying a Berger-grain 140 VLD, and maybe a GTB 140, or *something* else. That would give you a tangent ogive (Sierra), VLD-secant ogive (Berger), and less radical secant (GTB).

* * *

From your two targets, I'd say your load is promising, but not there yet. That's on the assumption your shooting is "quite good." If so, I'd go up in powder, if you're not seeing any signs of pressure now. Half-grain at a time. Of course, if you're seeing pressure, you have to go the other way.

Slight improvements in group size, and big improvements in consistency come from getting the seating depth dialed in for that bullet/barrel combination.

EDIT you reposted while I was writing:

For contemporary loading data, the 6.5/06 (plain Jane) is very, very close to the 6.5/284. Just start with that data.

Just ignore that 3,200 fps stuff with a 140 grain in a 6.5/06. I've done that with an Ackley Improved (3,300 actually), but that's with a very stiff charge of Rel-22 in a 30-inch Shilen ratchet-rifled barrel. BAT action. With your setup, I'd guess the 2,900 region is about right.

* * *

If you're near Burney, say hello for me. Its been 50 years. Was real nice country then . . .

11-24-2010, 11:41 PM
Thanks to all the above. I'll plink away and report back next week. Hopefully you wont be too busy to offer some additional help.
Way back in 98 or 99 I went through all the available hunting bullets, and also with my Swede. At that time, the Sierra 140 hunting bullet shot best in my 06' and the Hornady 160 RN best in the Swede. I 'll run through another Sierra box or two first, then try some Bergers if I can get any.

Edit: Be in/near Burney next spring for the trout opener !! I'll breathe in some cold mountain air for you !!

11-25-2010, 12:45 AM
I can't tell much by your targets but it looks to me that your load needs tuned. I think you also have some wind effect there.

Try this.


It is rare that I don't find a load that is competitive at 1000 yards (Benchrest) doing a single ladder test for a new rifle/ cartridge. I usually do .2 grain steps unless it is a large cartridge then I go .5 grains. I shoot over a chronograph and check both vel spreads and bullet point of impact between load steps to pick my load.

I do my load development at 200 yards.


brian roberts
11-26-2010, 07:45 PM
strictly black and white target, because it is much easier to see what is occurring using that stark contrast.
With the target you're using, you are attempting to accurately place black crosswires on a black target.
Oh yeah, I see those dandy yellow lines, they're just there to make the job more difficult, since it sells more of those targets, don'tcha know??
For an economical target, I use the Leupold sighting-in target, because with the four black blocks, it provides four aiming points (obviously I don't use this target the way Leupold recommends, either). When you have progressed to the point where the load is getting more promising, then you may wish to start using a BR-type target. I have found with the day-glo targets, the color "bleeds" over the wires, giving one an indistinct aiming point. I haven't ever used any other color since that discovery.

Hope That Helps :D

11-26-2010, 09:12 PM
Again, thanks all above. In two days I have been given a lot of good advice. The reason I used the shoot N see targets was to see the little .264 holes at 100 yards. I now know that is unnecessary, I just need a good black Cross on a white background I can see at 200 yards to aim at. Cheaper, better, what else ? Just made up some this AM before I read this. .. .. Let the group (s) fly. Slowly, over teh Chron, 3 or 5 at a group. Four groups, stop. Run a patch or two. Bring in the target, take the notes with velocity difference. Enjoy an iced tea. Maybe shoot another similar batch with same range of powder, different bullet seating depth. That simple. < 40 shots, but every one a source of documented data. Out to the loading bench...... As long as it stays fun and I understand what is going on. So.......... what are All those other guys doing out there blasting away flipping brass at me ?? Lots of good info at 6mmbr.com. I am going to take my 46.8 and use it as a near low load and work up starting at 46.5, 47.0. 48.0, 49.0 and 50.0. I have already shot 52.0 grains but it was wasted just plinking with my bro. But I know that is safe in my weapon. Any comments are welcome.

11-26-2010, 10:02 PM
I have just a few comments.

To Charles, well, I would not have guessed powders in the 4831/R22 burn rate to be competitive in those cases, and definitely not in your neck of the woods. Guys here complain about the 22 getting too hot so I'd have thought it no good for you.

Next, to Flouncer,
Load some ammo for 1K use, and take that thing to the range to plink that gong. Yer wasting bullets afaic. Once you've gone and shot some at the gong, you can come back and see what improvements are made with your load development. You stand a good chance of learning more that way. It's also nice to see improvement. Especially when you're first starting out.

That load with the 142 at 2400 seems a bit too slow for my taste. A chart may say that will still be supersonic at 1K, but I seriously doubt it'll make it there. An absolute minimum for me would be 2650 and I'm saying just hoping it would make the trip. Maybe they will, but, it's cutting it close. I only ever had 2 6.5's, and neither of them were ever tested to see how slow they could be shot for 1K use. To be competitive, I wanted to be in the typical velocity range so I didn't test things like that. I'll defer to others who've found the low velocities, and I'm sure Charles can give you that info (probably for every bullet in every twist).

Charles E
11-27-2010, 05:15 AM
Don't close your jaws, Phil, you'll bite your tongue. I guess when you said "faster powder in post #8, you meant "something that'll give a higher speed" rather than "faster burn rate"?

The below with a 6.5/06 Ackley Improved:

I never tested below 3,000. With the first barrel, about 3,050 with a 142 SMK gave best results. We could get 3,200, but it wasn't as accurate.

With the second barrel, I could get 3,100 with a 150 Clinch River (not generally available) and "more" with a 140 Clinch River flatbase (not available). Those flatbase bullets were awesome, BTW. Tooley & Shelp won a bunch of wood with them, and I had smallest LG group of the year at Hawks Ridge. Oh, they blew up a fair bit . . .

* * *

Flouncer: Speaking of bullets, the 142 SMK isn't a game bullet, so Sierra says. Before we get any deeper into this, where are you going with this rifle? Hunting larger things? Long-range varmint shooting? Fun in the sun?

11-27-2010, 10:59 AM
Some clarification as I and we drift slightly off course into the very broad range of the topic at hand. Essentially, for me, it is evolving into why and how fast little spining objects hit precisely where you want them. And that is a science for people, enthusiasts, with some spare time. So..... First, I typed my load in my second post in error. My load that really got my interest is actually 48.6 grns, and that is quite a bit more than 46.8. I was encouraged because when I got home, the spread measured center to center, was .56 and .62 inch, way better than I ever remember shooting. And, in both groups, there were two, 2-hole groups. Bullet through a bullet hole. For a real old crusty wood stock Military Mauser, that got my giigy going. I found one of my old Midway carboard ammo reloading boxes from 1998. My sweet load with 50.5 grains H4831 and Sierra 140 SPT Hunting bullet, 3.300 CAL. That load and bullet at that time out shot any and everything I tried, at 100 yards. Even the 140pr HPBT match. And I shot everything from IMR and Hogdon, that was in the Sierra Manual. I still have boxes of Hornady, Speer, Nosler, Barnes X in every imaginable weight. I got my first deer that fall, the shot was less than 60 feet, har har har. Coulda killed it with a spear. Bullet went clean through and I never found it. But I ate well. My son at age 3 knew where meat comes from.........

My re-vitalized intent is to gong at 1,000 yards. With existing equipment. To do that, have to get the best possible group, and a reasonable velocity that is still supersonic at the the target. And with my Cartridge, that isn't hard at all. Just for comparo, I looked at .308Win and .223 and they can just make it, maxed out loads with really long barrels...... As a family, we are cashed out. I am going with what I have. Recall it's a 1912 Model 98 re-barelled to 6.5-06. The stock, the parts that go click are within a blink of a century old. And I have a 1998 Tasco 6-24/40 scope 1-inch tube. Not the brightest or easiest to adjust, but I can see clearly at that distance. Dayton Traister (sp ?) triggeer, actually very nice compared to the mil 2-stage that came originally. I am used to it and easily snick off a click. So my thought process is that this time around I am going to learn everything that I can, and teach my son, now a young man, some firearms safety culture, and just plain fun. And on the way I have almost sucked in my ultra liberal Berkeley living pro gun control brother. I know once he starts shooting and stepping into the game the politics slowly will change, and once they do, they never go back. He has a first gen Ruger mini-14 and it is embarrassed by the 100-yeard old rig at the range. As only brothers do, he is stepping it up and will return with something new, expensive, and no doubt better. The joke is on him.

My 12-year old $59 Chrono still works fine with the similar aged battery !!

Anyhoo, 48.6 grns is probably closer to 2700- 2750, but I will probably end up near 50.5 grains, which I definitely recall was 2880 fps with the 140 Sierra Spitzer boat tail hunting bullet. Same box of 1,000 Federal 210M primers, away we go with a similar but different bullet. Same Lee collet die. Again, my aim (pun intended) is to gong at 1,000 yds. I am just plain lucky that I have a big case to work with, and some very good bullets that have the potential to easily accomplish what I want. If this effort is successful, I will try with my Swede in 6.5x55, but that weapon is limited with a straight bolt and I am not going to drill and tap the receiver for a scope just yet.

After I get a consistent 0.5 inch group at 100 yards, and something close to that MOA at 300 yards, I get to play with the scope and shims to get the necessary elevation for 1,000 yards. Redfield 1-piece base and rings. Maybe some other new shooter/reloaders can read this thread and get into the show.

Fun in the Sun !!!!!

Edit: Available range work is off a concrete shooting bench with sand bags. After Santa, a Harris Bi-pod.

Dog's Elvis
11-27-2010, 04:08 PM
Those groups will likely get better if you increase your velocity to 2850 or more.
Then, play with seating depth.
Third, you can experiment with different primers.
I favor H4831 over R22 because H4831 is less temperature sensitive.

Fred J
11-27-2010, 04:54 PM
With the age and type of scope you use, I would check the parallax. Over the years, the internal of those scopes changed. When shooting groups, developing loads, or just trying to get the best out of your ability and equipment, and bad scope can cost you.

Charles E
11-27-2010, 05:00 PM

1. Barrel life with a 6.5/06 is somewhat limited. You might get 1,500 rounds. Testing, therefore, should have some limits . . .

2. Greg Culpepper shot his 6.5x55 Swedish army rifle in the 1,000 yard "factory class" for a while. He did quite well with it, including a couple wins. It did have a scope.

I'm back to aligning with Phil (4Mesh). Shoot at the gong. Have fun. Someday, if you find your interest still piqued, get a true long-range competition rifle. When the bug bites, there is nothing else that will satisfy.

* * *

(Actually, I was in Montgomery Creek. Burney was the big city . . .)

01-04-2011, 09:02 PM
Just thought I would check back in. Was at the range today, er, I mean I left work sick at lunch........ Off the bench at 100 yards, the handloads found a sweet spot. From a previous session with the CHRONY, the 142 SMK are averaging 2832 fps with 50.5 gr of H4831. Today, I was going to shoot 11, 4-shot groups. I worked up starting at 48.6 and stopped at 51.3 with the groups opening back up, some firing pin splash, and early signs of flattened primer. 51.0, however, was the best I have ever shot, and that 4-shot group makes a nice little triangle that is 0.545" across, outside edge to outside edge, and 0.384" center to center, as best I can measure. My thinking about group size is that the outside to outside distance minus one bullet diameter should equal or be the same as the center to center measurement. It is not in my case. What gives ??

I'll try the 300 and 600 yard ranges next week with loads in this vicinity.

How, exactly do you all measure group size ??


Joe Haller
01-05-2011, 01:24 AM

Both your groups have that 10 o'clock to 4 o'clock pattern.

That "could" mean WIND.

With the right hand spin of the bullet, a wind from 9 o'clock will drift the bullet down a little (about 25% as much as the drift to the right).

A wind from 3 o'clock will drift the bullet up a little.

Same idea as the spin put on a baseball by a pitcher. Same thing that causes an airplane wing to lift the plane. Some folks call it the Bernoullii effect. Others say it's got to do with the bullet pointing into the wind.

Anyway with only two groups, it just one of may possibilities. If you see that 10 o'
clock/4 o'clock pattern on several groups, it might be telling you ya better learn more about wind drift.

Ya got some wind flags out there when ya practice?

Joe Haller :-)

01-07-2011, 09:32 PM
Thanks Joe. Here are pics of the above firing...... Yeah, there's flags all over the place, and in this case, I could feel it .. .. .. COLD !! Maybe 5-10 mph left to right, almost 90 deg and perpendicular to the axis off flight. But it's only 100 yards and I tried to time the wind .....



.. .. .. and here is where I called it a day, and the primers looked abused. Not able to get a decent closeup of the primers with $100 Fry's camera.


brian roberts
01-20-2011, 10:36 AM
Flouncer, you have a private message...