Range Report Ladder Test @ 300 yards. Advice/Interpretations

[AMG04]

This weekend I was able to shoot an initial ladder test at 300 yards. The aim point on target is a 3" circle for size reference.
Load Data:
5.56x45/.223 16" AR
Bullet: 65gr SGK
Powder: Varget
Primer: CCI.41
Brass: Lake City '11

1. 24.6 N/A Sight in on paper, adjuested -2MOA.
2. 24.8 2599
3. 25.0 2650
4. 25.2 2666
5. 25.4 2656
6. 25.6 2710
7. 25.8 2743
8. 26.0 2743
9. 26.2 2766
10. 26.4 2801 slightly flattened primer.

25.6 and 25.8 impacted at the same horizontal plane, but it is a small margin for error. Is this the node I should load within, or should I look around the cluster between 25.0-25.4 even though there is more vertical dispersion?

Your input and advice will be greatly appreciated.

 

[Unknown]

Re: Ladder Test @ 300 yards. Advice/Interpretations

With results as "inconsistent" or erratic as that, I would want to repeat the test a couple of more times to find out if something odd was going on. Factors I would look into before repeating the tests though:

1. Did you start with a really clean bore? Often, until the barrel is "seasoned" or your get all the cleaning solution out, and get some fouling into the barrel, the rifles don't shoot consistently. I have some rifles that season with only 2-5 rounds, other rifles take around 20 rounds before they really settle down.

2. Was there a change in wind direction? As you know, even having wind coming from 12 or 6 O'clock can cause changes in elevation. If the wind was shifting from 12 or 6 O'clock, to either 3 or 9 O'clock, that would explain both the shift in elevation (rounds above the dot) and the shift to the right (rounds lower and to the right).

3. Is the rifle's action torqued down properly? If it is a bolt gun, and either the screws are not tight, they loosen, or the rifle is being seated down into the bedding, the impact can shift while this "settling" or change of torque is happening.

4. If the rifle is a semi-automatic, a gas block that isn't really tight, or one that has not been loc-tite'ed will cause shifts like shown here.

5. Check scope, rings, base, mountings. If I didn't know better, I would suspect that something happened to your system (rifle, bedding, scope, mounting system, wind) that causes this result.

6. Lastly, consider shooter impact on the groups. All of us have bad days on occasion...that is just part of being human. Too much, or too little coffee, not eating right the day before, (or that morning), sleep problems, alcohol, tobacco (or even the lack thereof for addicts) can have effects on our shooting.

After considering all the above, and checking everything out, I would run the tests again a couple of times. If you can repeat the conditions of the original test as closely as possible, it might be helpful to run the same test 2x on the same day, then compare those results to the previous result.

 

[AMG04]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Unknown: Thank you for the detailed response.

1. I did shoot 5 shots to foul the bore, however I have noticed in the past the rifle does settle down and tighten up after an entire day of shooting. My personal best group was the last group fired at 200yds, after shooting 75 rounds of various loads. Prior to next test I will load about 20 rounds to shoot and foul the bore while at the same time warming up and getting comfortable as a shooter.

2. Winds were primarily 9mph from about 7 O'clock, but did shift occasionally and come from 5 O'clock.

3. Semi-auto

4. This statement was news to me! Very interesting. My gas block fits snug, but I did not use loc-tite. I have some on my bench and will apply it, especially if it helps eliminate POI shifts.

5. There is a new scope on the rig, I will triple check to make sure things are tight.

6. This is were you start to find all the problems... Just in the past year have I started moving past the 100 yard line. So I do need to practice and keep working on form and technique. The rifle has a solid bi-pod and I was using a rear bag. I do practice alot of dry firing, but am still working on follow through after the shot. It's all a work in progress, and very addicting!

Thank you for your advice, I feel like I have a place to start now. I should be able to load everything this week and shoot this weekend. Results to follow.

Thanks again,
Austin

 

[TwoGun]

Re: Ladder Test @ 300 yards. Advice/Interpretations

I like trying to interpret these. I have very little experience but this is how I see it. To me the arrows represent motion in the barrel. The first shot is 3.3" high. Assuming you adjusted the scope 6.282" lower in the subsequent shots, the first shot is about 3" low and would be included in the #3 & #5 shots.

 

[AMG04]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Thank you TwoGun:

After reading Unknown's post I have some things to check on my rifle, but will be shooting another test or two this weekend.

The arrows add a nice touch, and there could be some potential with 26.0-26.2.

For some reason I can't attach the photos I measured with On Target, but if you measure the 3 shots 25.0-25.4 it measures 0.429 MOA. That too may have some potential. It looks to me like the barrel is at a "settled" point on the low end of the vibrations.

If I understand the ladder test correctly you are looking for a Node in which the barrel vibration has paused at either end of its vibration pattern? So the goal is to have consecutive shots that impact almost on the same horizontal plane. Is that correct?

Its all a learning process and I appreciate the response, its good food for thought.

Thanks,
Austin

 

[TwoGun]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Yes, that's how I understand it. The highest and lowest shots are not a node though (my opinion). High shots and low shots occur because the barrel is moving as the bullets exists. You can actually get better groups at times outside of a node. The trick is to get reasonable groups but eliminate fliers. The nodes are less likely to produce fliers and ultimately give the best performance at long range.

That's what I get from it having read various articles on the subject.

 

[tobias]

Re: Ladder Test @ 300 yards. Advice/Interpretations

The bullet should leave the barrel when the muzzle is at a dead center of the oscillation (up or down). Then a small variation in load (or muzzle velocity) has only a small influence on the point of impact.

 

[TwoGun]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Also, from what I've noticed, the nodes will be closer to the bottom shots than the high ones. The reason for that, I believe, is the gun is recoiling upwards and amplifies the movement of the bullet when the barrel is in it's upward travel. When the barrel is moving downwards, the recoil of the gun cancels out some of that displacement.

Your pattern seems correct when I look at it. Good shooting.

 

[shoot4fun]

Re: Ladder Test @ 300 yards. Advice/Interpretations

24.8 thru 25.4 look good to me.
I think you may have been coming into another node at 26 to 26.2 grains.
The 26.4 probably moved way up due to erratic SD caused by pressure issues.
Just my opinion though. I am not a pro at this.

 

[AMG04]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Shoot4fun,

Thank you for the insight. I'm looking forward to seeing the results from further testing. 25.0-25.4 seem like a nice place to start. I prefer accuracy over velocity.

Im currently building a 260rem to get me feet wet in long range shooting (just need a stock). In the mean time I am working on my loading/shooting technique with my AR. Im trying to get as much trigger time as possible.

Any additional tips and advice is always welcomed.

Thanks again for posting.

-Austin

 

[ChadTRG42]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Why not just load up 4 or 5 rounds in each charge weight at the high end of the powder charge and see how they group? It's much simpler and you won't waist range trips. Forget the ladder method.

 

[TwoGun]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Because the ladder method reduces the chance of fliers regardless of group size. Short to medium range benchresters could care less about the ladder method. If they find a load that produces awesome results but only throws a flier 5% of the time, they'll take it. At long range for score, say shooting 60 shots to 80 shots those 3 or 4 fliers will screw you. It just depends on what you're trying to accomplish. The 5% is a little exaggerated to illustrate a point. Sometimes a single flier is enough to ruin your day.

From a non-competative point of view, it doesn't really matter.

 

[ChadTRG42]

Re: Ladder Test @ 300 yards. Advice/Interpretations

IMO, fliers are caused from other reasons, like poor brass prep, different neck tensions, and anything related to the components. If you are shooting in your node, you should not get the fliers. The fliers I have seen were traced back to brass issues, not powder or node issues.

 

[ChadTRG42]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Here is a typical target that I see when I am doing my load work-ups. I shoot 5 rounds in 1 charge weight and see how it does, and go up from there. You can see the groups and the consistancy improves with each increase in load. When you are not in the best accuracy node for the rifle and bullet/powder combination, you can see it in the group size and the consistancy in the chronograph. This was done in 21 rounds. There's no fliers in the top right group. If you get fliers, something is causing it with the components or you are out of your node.

Middle- first load
Bottom left- 2nd
top left- 3rd
top right- 4th and last load

 

[Unknown]

Re: Ladder Test @ 300 yards. Advice/Interpretations

Austin,
Although I hate to admit it, I find that on days when nothing makes sense, it is usually traced back to me having a bad day for whatever reason. After decades of shooting, I know how to eliminate many of the variables, but even when I do that, there are some days when I couldn't hit the ground with my ass if I picked both feet up at the same time. As shooters are usually a very competitive bunch, and work hard to control variables, most of us have great difficulty admitting that we simply suck at shooting some days.

On those days, I accept that I'm having a bad day, and try to end my range session by coming up with a exercise on which I can succeed. I think it is mentally important for me to leave the range on a positive note..even if all I do is shoot my long distance rifle at 50 yards to make myself feel better.

Edited to add:

Semi autos require different technique pulling the trigger than bolt guns. It is still trigger control, but things you can get away with on a bolt gun will cause you problems with a semi auto. You have to be really consistent on controlling the trigger in both directions, and rest the rifle in the same place every time.

For semi autos I would check

1. your trigger pulling technique
2. are you mounting the rifle on the rest, and your body the same way for each shot
3. are you allowing any tiny crescent shaped shadow to creep into the scope's edges because of a problem with eye relief, or cheek weld on the stock. The crescent shape always throws the shot to the opposite side of the scope.
4. any change in your body position from shot to shot, either in relationship to the bench, ground, or rifle can make a change in impact.

There are some excellent tutorials on this site that discuss the how and why shooting semi-autos are different. You might also check youtube for some tutorials..some are good, and some are so bad they seem like a sarcastic jab at shooting instructors.