December 10, 2022Saturday Movies: Finding length to Lands — Multiple MethodsSetting the optimal bullet seating depth is crucial for maximum accuracy. Some cartridges and barrels can deliver excellent accuracy with a wide variety of bullet seating depths. However, some barrels are more picky and may prefer a particular depth such as.006? in the lands and.020? off. This precision can only be achieved if you know exactly where the lands are in your barrel. You should also know the exact position of the lands in your barrel, as barrel throats can move with increasing round counts. Saturday Videos today show a variety of methods to determine the Length to Lands of your rifle barrel. The Hornady O.A.L. is the most popular method. A modified threaded case is used to gauge. This is possible with some practice and a fine touch. We offer videos with alternative methods, each with their pros and cons. Finding Cartridge Length to Lands using O.A.L. A Hornady O.A.L. is the best way to determine length to lands. Gauge Tool with a comparator and a set of calibrators. This method is often used with a modified case for our 6mmBR rifle. We can achieve results in.0015 using the technique below. Three out of four times. Multiple measurements are recommended. We recommend taking multiple measurements. Take your time, slow down. Here are FIVE TIPS to help you get reliable and repeatable length-to-lands measurements using the Hornady O.A.L. Gauge:1. Start with a clean chamber.
2. The modified case should be securely screwed down and placed on the OAL Gauge. Sometimes it can come loose during repeated measurements.
3. Place the modified case slowly, but gently, into the chamber.
4. Push the gray plastic rod VERY CAREFULLY. It is not uncommon for the bullet to be slightly tilted. Before you apply pressure, let the bullet center in your throat. Tap a few times until you feel resistance. Do not push too hard, as this will cause the bullet to jam in the lands.
5. You should repeat the measurement at least three more times. If you follow our instructions you should usually get a repeatable measurement within 0.0015? Typically, you should get repeatable measurements within 0.0015?. They were pushing too hard on the gray rod and going too fast, creating a hard jam. Modified Gauge This Brownells video demonstrates how to use the modified (threaded), case for your rifle’s cartridge. Attach it to your O.A.L. Then, attach the gauge to the O.A.L. It takes some practice to achieve consistent results. It takes some practice to get consistent results. Gauge. The gauge is made by drilling out the primer pocket, tapping and threading the bottom of your case. First Gavin Gear demonstrates how to use the Hornady O.A.L. Modified Gauge. The second method shows how to use Loctite inside the neck to secure a bullet. Make sure that there is no Loctite outside the neck. You don’t want it in your chamber! Place the case and bullet in the chamber. The bolt will then be closed to secure the bullet. After waiting for the Loctite time to set, you can gently remove the cartridge. Time-mark 16:50 is the third method. This involves a Jam method that uses a bolt with the firing pin assembly (and ejector) removed. This allows for no additional pressure to be applied to the case. Gavin notes that the bullet ogive can be colored using a permanent marker to indicate lands contact. Erik Cortina, an F-Class ace shooter, posted about this third Jam method: “My method was actually the last one Travis showed. This is the one that lets the lands push bullets in. It is dependent on neck tension. To prevent bullet ogive from sticking to the lands, I also put die wax into bullet ogive. The Alex Wheeler method is a way to seat a bullet deeper and deeper until it closes. There are many ways to measure this, as you know. “Finding length to Lands the Speedy Method” This is another way to determine length to land that works with an unmounted barrel. Thomas “Speedy”, a top gunsmith, and ace benchrest shooter, explains this method. Speedy inserts a bullet into the chamber, then adjusts the depth of the seating with an inline seat die until there is no resistance or sticking. Speedy can then easily adjust the length to lands with his micrometer-sized seating die. Speedy’s method is recommended if you don’t have a modified bolt and don’t want to disassemble the bolt to measure it. This allows the bolt to be used to smoothly advance a bullet-filled case into the chamber. The bullet will then return to the “first touch” contact position. Next, remove the case slowly and measure. We will show you how to measure the length of your rifle’s lands using a caliper or bullet comparator. NOTE: A Modified Case from a store may not give the exact same length as your own fired case. This is true, but it is important to note that the Modified Case may not deliver the exact same length from case base to lands as your own fired case. Simply take a neck-sized, fired case with no primer and cut the necks vertically using a Dremel. This will ensure that the bullet is held in place when you chamber the loaded round. The bullet will move back as soon as it touches the rifling. The bullet will slide back into the case as the cartridge chambers. This will give you the length to land. Although it is not perfect, this is good enough to determine the length to land for hunting rifles. The video maker explains that there is no need to buy gauges if you are willing sacrifice one case. This method can be used with patience and a little time. Additional explanation. How to adjust tension — Length, Number of Neck Cuts
Andris Silins from Forum explains that she uses this method. There are two ways to adjust tension. You can make the cuts shorter or longer. You will get less tension if you make the cuts longer. You would get more tension if you only used three cuts instead of 4. It is important to be gentle when opening and closing the bolt. You could accidentally ram the bolt shut. It is a good idea to keep a few fingers near the case to help it straighten out when you open it. The ejector will push it sideways so it is best to keep one or two fingers close by. READ MORE.Finding the Lands With HK Rifleworks Another video shows how to disassemble the bolt so the firing pin assembly & spring don’t apply pressure on the empty box, which could affect the bullet as it touches the lands. The video maker demonstrates how to quickly disassemble the bolt using a Brownells bolt assembly tool (3:20 mark). Once you have a repeatable measurement you will know exactly where the “first touch” is. You can adjust your seating depth so that it is into the lands or jump the bullets. Many benchrest shooters prefer to load “into lands”. Hunters and PRS/NRL shooters will prefer to jump their bullets.0020? Or more.
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