This Article/Blog was published by RifleShooter Magazine Online. (Dec 14, 2021) Due to contract obligations, I am not allowed to post this on my website for one-year. The published article can be found here:
Acknowledgements: This conglomerate of information has been accumulated, piece by piece, from years of discussions at matches, online research, and road trips with accomplished shooters. Many competitive marksmen like Al Nyhus, Don Crunk, Dean Walther, Craig Nagel and Hall of Fame members Mike Bigelow, Randy Robinett, Jack Neary, and Speedy Gonzales have been gracious enough to share much of this information.
Have you ever eaten something and it did not agree with your body? Heartburn was your system’s way of telling you not to eat those habanero peppers ever again.
Rifle barrels will communicate in much the same way. The barrel will give signs, based on what it needs, to perform at the highest level of precision possible. Here are a couple languages the tube will speak.
Time to Clean
Every barrel has a precision window; the number of shots, between cleanings, where the groups are the tightest. This window is largely dictated by the amount of fouling in the barrel. What differs, amongst barrels, is the starting point and width of that window.
The vast majority of tuned rifles will shoot better with some fouling. The process of shooting rounds to enter the precision window is called fouling the barrel. Starting with a clean barrel, the tube will tell you it has entered its precision window when the groups quickly tighten up.
Precision will start to decline once the barrel exits the window. For most barrels, this initial increase in group size is very slight. However, the farther from the window the barrel gets, the louder it will scream it is time to clean.
Use Scope Shield Scope Covers when traveling, in the field, storage and cleaning. Click to order.
Best Tune for the Rifle
Group shape is the main jargon when finding the best tune for the rifle. Here are six common group shapes and what they could mean.
Vertical stringing is typically the barrel’s way of asking for an increase in powder charge.
Y axis groups may also indicate the front bag is too hard on the shooting rest.
A horizontal group might be a weather report, meaning the shooter missed changes in the wind. However, X axis groups could also be the barrel saying there is a seating depth issue and/or it wants a slight increase in powder to drive through the conditions better.
A diagonal group might be your barrel’s way of requesting an adjustment in neck tension.
A 3/2 or 4/1 pattern is an indication that your load is getting too hot. Try decreasing the powder a few clicks. Pressure signs may also accompany these groups.
A barrel that is getting too hot can also start "throwing shots". If a knot is forming, then a shot goes out, check the temperature of the barrel before making any adjustments to components.
The dreadful train wreck; no two bullets are close to touching. Lots of things could be wrong. Assuming no equipment malfunctions or horrendous shooting conditions, major changes are needed to powder charge and/or seating depth. Train wrecks could also indicate there is a wrong bullet/powder or bullet/twist rate combination.
When the round cluster configuration is formed, the barrel is saying it likes what you are feeding it. Keep in mind, the size of this cluster is relative. A custom rifle’s circular cluster should be smaller than a group from a factory hunting rifle. However, the overall round shape will remain the same in tuned rifles.
Time to Retire the Barrel
Barrels are similar to car tires. With use, they eventually wear out and need to be replaced. Just like car tires, not all barrels wear out at the same rate. Do not fret. When you listen, the barrel will give some signs it is getting tired.
Toward the end of its life, the barrel will start shooting increasingly larger groups. Initially, these slightly bigger groups are hard to decipher. Did I miss a condition? Is it time to clean? Is the tune changing? Or... is the barrel saying it is close to being used up?
A tiring barrel will also produce some signs that are easier to interpret. Cleaning patches will gradually start becoming darker blue due to the barrel scraping off more copper. Another sure sign is the increasing amount of time and effort it takes to get the barrel clean. When added together, these signs all point in the direction of a barrel that is nearing the end.
Occasionally the barrel corresponds very softly and we have to strain to hear it. These subtle whispers are the small changes in group size or the slight changes of color on the cleaning patches. Other times, the barrel is broadcasting what it wants. For instance; the first few shots getting into the precision window and the shapes of the groups when tuning. Regardless of volume, barrels are always communicating. We just need to listen. Until next time, enjoy the process.
