I enjoy shooting. Specifically, I enjoy precision shooting. There is something internally satisfying about shooting small groups or hitting a demanding target. If you are reading this blog, then you probably have the same motivation.
There are many pieces to the precision puzzle. Good bullets, good barrels, and good equipment are all major pieces. Tuning ties all the physical pieces together. Tuning is a systematic process where the shooter adjusts the reloading components (load) to achieve the best precision (smallest groups) possible. When making the next decision in the load development process, group size and shape are the dominant influences.
During tuning, we want to ensure the only variable that affects group size/shape is the single component we are testing. Introducing other variables can lead to unreliable data. Producing unreliable data is worse than no data at all and is a waste of time. Do not let the following factors squander away your time.
1. Tuning Outside of the Precision Window
Every barrel has a precision window; the number of shots, between cleanings, where the groups are the tightest. What differs, amongst barrels, is the width of that window. Trying to tune outside of this window is a waste of time because not enough or too much fouling in the barrel adds another variable that can affect group size/shape.
Solution:
When shooting a clean barrel, take (at least) one fouling shot before shooting the groups. Tune while the barrel is inside the window. Clean the tube when it is nearing the end of the precision window. Just a heads-up: custom barrels routinely have a larger precision window than factory barrels.
For a complete explanation of the precision window see the Blog titled; “Cleaning Part 1: Know When to Clean”.
2. Tuning with an Unstable Rest
This should not need to be stated, yet it is done all the time; a shooter testing different loads while using a wobbly rest. Then, they get all excited that one load shot .2” better than another load.
A muzzle angle change of just 0.01 degrees can translate into 0.63” of movement at 100 yards. Shooting off an unstable rest is adding in another variable that is very difficult to account for. Pretty easy to see that time is being wasted if the rifle is moving before the trigger is pulled.
Solution:
An easy way to find out if your rest is stable enough is to look at a small target through the sights. (For example; a half inch circle at 100 yds.) Any movement will quickly be noticeable on target. No use in wasting time and components if there is not a solid hold on the bullseye.
3. Tuning During Heavy Mirage
Mirage is the bending of light rays as they travel through layers of air with different temperatures. This optical illusion will cause the sight image to “dance” around. Mirage usually occurs at times when there is considerable sunshine. Few shooters can get reliable tuning data while shooting in this condition. It is very difficult to get the consistent aiming point needed while doing load development.
Solution:
Tune in cloudy or low mirage time periods. Checking the weather forecasts for cloudy conditions can allow you to preplan your load development. However, if you are a competitive shooter, mirage conditions can be great practice.
4. Tuning in Extreme Temperature Differences
OK…so this isn’t exactly a waste of time. However, tuning in temperatures that are drastically different from the temperatures you will be competing or hunting in is something to be mindful of. It is a well known fact that temperature affects tune. The longer the distance and/or the greater the precision needed, the more important understanding this information is to the shooter.
Solution:
The majority of short range Benchrest shooters load at the range or have tuners on the end of their barrels to compensate for changes in the weather. The biggest biggest piece of the weather puzzle; temperature.
Hunters do not have to be this anal. There is a larger margin of error for hunting than in competition. However, cartridges designed for hunting rifles are not immune to the temperature induced changes in group size.
There are two items that will help the balancing act between temperature swings and precision. First, research and try temperature resistant powders that will work in your cartridge. (Hodgdon Extreme Powders for example) If needed, be willing to give up a little precision to gain the reassurance the group size will not drastically increase when the temperature changes. Second, record the temperature while first finding the best load. When possible, check the same load when temperatures are within twenty degrees of the average temperature the hunt will occur in. Do not be surprised if you have to make slight changes to the powder charge. The closer the temperature is to what you will be competing or hunting in during tuning, the smaller the changes will be to keep the rifle in tune.
5. Tuning in the Calm
This is probably the most common time waster. Mistakenly, many shooters want to test loads during the calmest times of the day; morning and late afternoon. This information is going to challenge what those marksmen think.
There are a couple of reasons why you should rethink tuning during these calm periods.
Yes, windless shooting may produce some wallet groups; one hole groups that will amaze your friends and colleagues. However, these calm shooting periods can also produce some unexplained train wrecks; groups that have no defined shape, pattern, or even bullets touching.
There was a key word in that last sentence; unexplained. When tuning, unexplained is never good. This does not imply that every load will shoot small groups. Rather, there should be a reason for every group shape. If not, we are wasting our time.
Getting rid of the wind variable is theoretically a good idea. Realistically however, it is not. One of the goals of tuning is to develop a load that will cut through the wind. How can a load be developed to cut the wind if there is no wind?
Solution:
Perform the load development on days with low and steady winds. I routinely check the wind forecast by using this aviation website. http://www.usairnet.com/cgi-bin/launch/code.cgi?Submit=Go&sta=KLNK&model=avn&state=NE (You can change the location to fit your needs) Wind blowing harder than 10 mph is a great time to practice. On the opposite end of the spectrum, I heard top water lures work pretty well on calm days.
6. Tuning without Wind Indicators
Wind will influence the impact point of a bullet. Proper tuning will decrease this effect on the bullet. However, there is a realistic limit to how much the bullet can “cut the wind.”
If a shooter does not focus on the conditions and unknowingly shoots in an extreme change, it is very tough to know if the wind caused the bullet dispersion or the tune of the rifle. Again, if we do not know what caused the group size/shape then we are wasting our time.
Solution:
Lots of things can be used as wind indicators. A few examples are: watching the grass sway back and forth, feeling the breeze on the back of our neck, watching the mirage roll across the ground, and listening to the wind on the objects around us. Wind indicators are everywhere. We just have to notice them. Once we start recognizing indicators, we can use them to know when to shoot, where to hold, or when to wait.
I use wind flags when tuning. However, I am not trying to shoot in the exact same condition, like I would be in a match. When tuning, it is OK (even preferred) to shoot when the wind is blowing a slightly different angle or velocity. This way, we can tell if the bullet is cutting through the conditions like it should. On the other hand, we should not shoot in extreme changes (reversals, let ups, or pushes). Wind flags are a guide of when not to shoot just as much as they are of when to shoot.
It is important to note: There are some very accomplished shooters who tune with no flags. Their philosophy does have merit. They want the bullet to cut through the conditions no matter what the condition is. Pretty hard to argue that logic and very hard to argue their success.
My theory is that those “Hall of Famers” are still using wind indicators, just not wind flags. Through years of focused practice and competing in hundreds of tournaments, these top tier shooters are subconsciously noticing the effects of the conditions around them. In other words, they are not shooting in pushes, reversals, and let ups. The same thing that us “regular Joes” ensure when we use wind indicators.
7. Changing Multiple Components at Once
The main components when doing load development are; bullet, powder, seating depth, neck tension, and primer. All of those components can be adjusted to see what happens to group size and shape. A major key to tuning is to only adjust one component at a time.
When a shooter changes more than one variable at a time they do not know which change made the difference in the group. If you do not know what made the difference, it is a waste of time.
Solution:
To get reliable data, only change one component at a time. The abbreviated traditional route is; pick a bullet and powder. If using a resizing die that accepts bushings, begin with .002 neck tension. Seat the bullet at the 0.000” mark (jam length). Beginning with a light powder charge, start shooting groups with increasing powder charges (Watching for pressure signals along the way). Once the round, cluster shaped, group forms, see if the groups tighten up by varying the bullet seating depth. If you want to go further, experiment with increasing or decreasing neck tension, then different primers. The key is to only change one variable at a time. For a more in-depth look at the process of tuning see the Blog titled: Tuning Part 2: Handloaders
Every day is a good day to go shooting, but not every day is a good day to tune. The goal of tuning is to find the right recipe for a particular rifle. You will know the rifle likes what you are feeding it by the group shapes and sizes. When those groups are not reliable, we are wasting barrel life, components, money and, most importantly, time. I hope this blog helps you use your time more wisely. Until next time, enjoy the process.
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