What would make a 100yd group open up by a factor of 5x at 200yds?

[stacy]

EACH IS OWN BUT ITS HARD TO GROUP SHOT WITH A 9X SCOPE OR IT IS FOR ME 12X OR 15X MIN I CAN USE

 

[clunker]

I'm not an expert by any means, but isn't that a keyhole in your second pic? I thought those were a warning sign of an unstable bullet.

 

[Shinbone]

I have considered getting a dedicated fixed-power target scope. But, I am usually working up loads for multiple rifles at one time, so just one target scope wouldn't be enough. My wallet is already crying as it is.

I picked up in a trade a Swarovski Z5 3.5-18x44, with the BRX fine crosshairs reticle. I'll see if I can "limp" along with that optic for load development for awhile.

What looks like a keyhole is just where the bullet hole tore out to one side. All actual bullet holes are very round on all the targets.

 

[hambone1971]

Gun is an all-factory bedded Kimber Montana in .223 Rem shooting Berger FBT 55gn bullets over 26.4gn of AA2230 at 3400fps average velocity. These were shot off a bench with a front rest/bag and a rear bag. 2 foulers were shot from a clean barrel before the groups. 1 minute between shots, 20 minutes between the two groups. Close to zero wind.

I know MOA size can be expected to open up some as the range increase, but 5x from going from 100yds to 200yds is ridiculous.

I've used AA2230 with a lot better results but my load was about 3 gr less.
The Hornady book shows 24.5 max at 3200 fps for 5.56 Nato, nothing for Rem.
When you seat your bullets are they feeling the same from bullet to bullet when
they go in the brass? Neck Tension equal?
If your starting with a super clean barrel it's going to take more than 2 fowling shots to get it shooting. I wouldn't shoot for groups untill I had 10 or 15 down the barrel.
The other thing I wondering about is you mention front rest / Bag and rear Bag .. if possible shoot off a more fixed.stable front rest. Something with no give in it.
My ES is a lot less say 10-20, good luck.
HB

 

[Shinbone]

"When you seat your bullets are they feeling the same from bullet to bullet when they go in the brass? Neck Tension equal?"

I've wondered whether my neck tension is under control. I seat using a Wilson inline die and a 21st Century arbor press. No hydro measuring capabilities, though. Neck tension does sometimes feel different. In fact, sometimes I have to neck-size a particular case down another .001" to keep the bullet from "falling in." This is why I am switching from the Starline brass to Lapua brass.

I have the capability to trim necks, but such level of case prep seems a little over-the-top for a 200yd prairie dog gun.

 

[Bc'z]

"When you seat your bullets are they feeling the same from bullet to bullet when they go in the brass? Neck Tension equal?"

I've wondered whether my neck tension is under control. I seat using a Wilson inline die and a 21st Century arbor press. No hydro measuring capabilities, though. Neck tension does sometimes feel different. In fact, sometimes I have to neck-size a particular case down another .001" to keep the bullet from "falling in." This is why I am switching from the Starline brass to Lapua brass.

I have the capability to trim necks, but such level of case prep seems a little over-the-top for a 200yd prairie dog gun.

Are you annealing?
If your having to resize the occasional case it sounds like your having a bit of spring back.

 

[243winxb]

Neck tension does sometimes feel different. In fact, sometimes I have to neck-size a particular case down another .001" to keep the bullet from "falling in."

I see this as a major problem. Size the neck smaller then needed. Then open with an expander. Aim for .002" neck tension.

 

[Rdlningcltchdmpr]

I would be looking for a different or better bullet

It's not the bullet's. It's the powder, it's always the powder.

 

[Rdlningcltchdmpr]

Gun is an all-factory bedded Kimber Montana in .223 Rem shooting Berger FBT 55gn bullets over 26.4gn of AA2230 at 3400fps average velocity. These were shot off a bench with a front rest/bag and a rear bag. 2 foulers were shot from a clean barrel before the groups. 1 minute between shots, 20 minutes between the two groups. Close to zero wind.

I know MOA size can be expected to open up some as the range increase, but 5x from going from 100yds to 200yds is ridiculous.

The ES isn't great, but it isn't enough to blow up a group that much at 200yds . . . ?


At 100yds, group size is 1.15", ES = 104fps:





At 200yds, group size is 5.37", ES=120fps:




Had almost similar results with a Ruger Hawkeye in .223 Rem at the same shooting session.

At 100yds, group size is 1.05", ES=100fps:




At 200yds, group size is 3.66", ES=144fps:

It's the powder, it's always the powder. 1"+ groups are rotten. My 223 Tikka rifle's make between high zeros to 1/4" . 300 yard groups under 1" mostly with varget powder. I could show you groups of 1" at 100 yards with those same rifle's only using the wrong powder. It's always the powder that makes the accuracy difference.

 

[Nick Caprinolo]

Too much powder. Berger recommends AA 2320 at 23.5 to 25.9 grs. It's their bullet and they did the tests. I will bet that if you start at around 24.3 grs, your results will improve dramatically.

What is the barrel twist rate. It is recommended 1/14 or faster, for 55 gr bullets.

 

[Old Tanker]

You may also want to change your point of aim. When doing load development and groups, I never cover the intended point of impact with the cross hair. At 100, I line up on the lower left corner of a 1” square with the intent of having the group in the center of the square. This gives me a consistent and very small point of aim. I use a 2.5” square at 300. When shooting .22 rimfire on a benchrest target, I line the horizontal and vertical cross hairs tangent to the left side and bottom of the 9 ring. Also, breath, breath, breath. You can’t hold your point if aim much longer than a couple of seconds. Five seconds and longer and your brain/eyes start playing tricks. I learned this valuable lesson shooting off hand, international targets in small bore competition in college.

 

[Homerange]

I have considered getting a dedicated fixed-power target scope. But, I am usually working up loads for multiple rifles at one time, so just one target scope wouldn't be enough. My wallet is already crying as it is.

I picked up in a trade a Swarovski Z5 3.5-18x44, with the BRX fine crosshairs reticle. I'll see if I can "limp" along with that optic for load development for awhile.

I reckon that will open your eyes to precision shooting.

Oh yes doing a couple of rifles at a time would be problematic with just one target scope yet you can still do fire forming and/or velocity/ES checks on rifles with a hunting scope.
I find the choice of target helps immensely with precision shot placement when you haven's sufficient magnification.
Being I can just walk out the door more or less to my range allows me to just need one 4-16x magnification scope and yet it wasn't expensive at all, only some $150 landed and it lives on my 223 except when needed for other load development works.
Being from China the optics aren't top class but certainly good enough for my needs however I'd never take it on a remote trip in challenging weather.

 

[Zero333]

Years ago I was chronographing some loads and a young fella asked if he could chrono his.

So I shot his rifle with 10 of his 223 handloads thorough the chrono aiming at the 300 meter target.
The 300meter 10 shot group was barely over 1 inch, but the ES was over 100 fps

 

[chop house]

I'll see if I can "limp" along with that optic

i am no stranger to limping along when it comes to optics. it's the $$$. when i have to work with hunting optics i use a 'reverse' target so to speak. i print them up with the white space sized according to reticle subtension, and use them like iron dual peep sights so to speak, centering up the white space.

no need to use this much black, but you get the idea:

 

[CharlieNC]

You mentioned this is a hot load. When doing a charge weight ladder I have observed both the ES and groups get abruptly large at high pressures. Meaning the very high ES may not be the cause, but an accompanying symptom. You may be in that regime.

 

[Shinbone]

[My original question was "why a 5x group increase from 100yds to 200yds"?. Obviously, improving the group at 100yds, which a lot of folks are contributing to, is an essential step, so thanks for all that input, too.]

"You mentioned this is a hot load. When doing a charge weight ladder I have observed both the ES and groups get abruptly large at high pressures. Meaning the very high ES may not be the cause, but an accompanying symptom. You may be in that regime."

Looking back through my records for this gun, I see a potential accuracy node at about 3250fps for multiple powders: AA230, Benchmark, H335, and H4895. Of the three powders that didn't pressure-out before reaching 3400fps, only AA2230 showed a potential accuracy node at 3400fps. (Note: I just do a few shots at each charge weight while looking for the pressure max, so these potential nodes don't mean much until I do further testing.) AA2230/3400fps is where I started shooting for groups because I got suckered by the siren song of velocity. But, that four different powders showed a possible node at the 3250fps shows this is where I should have started looking for an accuracy load.

During pressure testing, H4895 showed the broadest potential accuracy node around 3250fps, but the charges are compressed enough that there is some slight marring on the ogive from the seater plug, so, I am not sure if I want to continue working with this powder in this rifle.

Anyway, I will choose one of these 4 powders and load/ shoot groups around 3250fps and see what happens.

 

[nawahine]

Trying different bullets are definitely a good idea.
I have .223’s in AR’s and bolt guns for p/dogs. For reasons (known only by the rifles) they like bulk 55-62 grain bullets (and V-Max, Nosler Varmagedon, etc) Loaded to around 2800-3000 fps usually loaded with CFE 223, TAC, BLC-2, and of course Varget. Once it hits that group.... that’s IT for that rifle.
Like others, I’ve gone thru a lot of makers, weights, configurations, and types (lead and “green” area) of bullets. Some work great and others not so; ‘’tis the reason I have a bunch of partial boxes.
Check with friends and mooch a couple of different weight and types.... you’ll find The One

 

[nawahine]

PS... hey Shinbone, PM me with your mailing address; I’ll send you some samples to try.

 

[Shinbone]

PS... hey Shinbone, PM me with your mailing address; I’ll send you some samples to try.

PM sent, and thanks for the generous offer!!

 

[David Milisock]

I'd try reworking the load and shoot 50 or 60 groups. I'd put my money on just bad 100 yard groups that look better than they really are.