Today’s video showcase covers bore-sighting methods and technology. Bore-sighting the old-fashioned way — by looking down the bore of a rifle at a target — is not difficult. With a conventional bolt-action rifle, visual bore-sighting can be done quickly and easily. Rest your gun securely on bags, remove your bolt and set up a 50-yard target with a large bright orange or black center circle. Look through the back of the action and you should be able to sight down the bore with your own eyes just fine. There’s no need for expensive hardware. In fact it may be easier to bore-sight the “old-fashioned way” rather than try to see a laser in bright sunlight at 50 yards (or even 25).
However, with lever guns and semi-auto rifles, including the popular AR15, M1 Garand, and M1A, the design of the receiver may make it virtually impossible to sight down the bore with the naked eye. That’s where a modern laser bore-sighting device comes in handy. For those situations where a bore-sighting tool is needed, we recommend a laser bore-sighter that fits inside your chamber. An in-chamber laser device, as shown below, is handy and has less safety risk than a tool which fits in the end of the barrel.
How to Bore-Sight Your Rifle in Five Minutes
This video from Australia shows the basics of the bore-sighting process. First set up a target 50 yards (or closer) from your shooting station. Make sure the rifle is well-supported and stable. When the target is ideally centered in the BORE of the barrel, then adjust the reticle on your scope to center the crosshairs on the middle of the target. Then, after checking down-range, take a few test shots. Finally, move the target out to 100 yards and confirm your zero, as explained at the close of today’s article.
Vortex Shows How to Bore-Sight Rifles
This well-made, informative video from Vortex covers the basics of bore-sighting. Bore sighting your rifle is a simple way to establish an initial zero to get you on target faster and save you ammo at the range. Thankfully, it doesn’t take a ton of gear or ammunition to bore-sight a rifle effectively. Video host Jimmy from Vortex provides a handy, step-by-step guide in this 10-minute video.
Bore-Sighting Using a Barrel-Mounted Laser Bore-Sighter
If you wondered why a barrel-mounted laser bore-sighter was off-center? Or if you want to learn how to use one properly, this video shows how to safely and properly zero a scope using a barrel-mounted laser bore sight device. Another option is a small cartridge-sized laser that fits inside the chamber. These sell for under $25.00 and are convenient. There are safety advantages to in-chamber lasers.
Initial Bore-Sighting at Home (Before You Head to the Range)
This useful video shows how to bore-sight a rifle at home. This can save time (and money for ammo) when you do get to the range to confirm your scope’s zero. This home procedure works best if the target is well-illuminated while the rifle is in a shadowed area, creating the best contrast. Also make sure the rifle is on a steady support — such as a portable gun vise or sandbags front and rear.
Bore-Sighting with a Red Dot (Reflex) Sight
As with conventional scopes, if you have a red dot sight or reflex optic, you’ll need to bore-sight your rifle, then zero the optic. [Reflex sights use a reflex lens to project a dot or reticle onto the target, whereas red dot sights use a flat, reflective surface to display a red dot reticle.] In this video, retired Navy SEAL Mark Cochiolo demonstrates how to bore-sight then adjust a red dot. Bore sighting allows you to zero your red dot so that your shots hit near your intended point of impact.
Learn More about Bore-Sighting with Tools
To learn more about bore-sighting, you can view a detailed article on the Warne Scope Mounts website. This features through-the-barrel images and discussion of tools that fit in the chamber or barrel to project a laser beam down-range. Shown below are cartridge-sized projecting lasers that fit in a rifle’s chamber. These are available for a wide variety of cartridge/chamber sizes.
WARNING: If you use an in-barrel laser be sure to remove it BEFORE chambering a round. ANY obstruction in the barrel can cause serious injury or even death if you fire a round.
Bore Sight Grid Tool with Arbors
The Bushnell Bore Sight with Arbors is a bore-sighting tool that many gun stores and gunsmiths use. This device uses arbors but does not transmit a laser.
You attach the tool to the end of the barrel and align it with your scope. A grid is visible inside the bore-sighter. Look at that grid and then and align your scope’s reticle with the grid. This Bushnell unit ships with three expandable arbors in 22-270 caliber, 7mm-35 caliber, and 35-45 caliber.
How to Zero a Hunting Rifle Efficiently
Once you have bore-sighted your rifle to get “on target” successfully, then you want to zero your optic so that the shot falls exactly where you want it at your target distance, typically 100 yards. This Vortex video shows you how to quickly and efficiently sight-in and zero a hunting rifle before heading out into the field. This video explains a simple procedure that lets you get a solid zero in just three shots. Of course you probably want to fire a few more rounds to confirm your zero before you head off to your hunting grounds, but this will let you get on-target with a minimum amount of time and ammo expended. This helpful video now has 3.2 million views on YouTube!
Fouling Shots and Cold Bore Condition
If you recently cleaned your rifle, you may want to fire two or three fouling shots before you start this procedure. But keep in mind that you want to duplicate the typical cold bore conditions that you’ll experience during the hunt. If you set your zero after three fouling shots, then make sure the bore is in a similar condition when you actually go out hunting.
What can happen when the bottom-most primer in a primer feed tube goes off? A big bang, that’s what. Some or all of the primers in the vertical feeding tube can go off in a chain detonation. That’s exactly what happened to Dustin Ellermann, Top Shot Season 3 Champion. Scary experience, but thankfully Dustin was not injured. He writes: “Super thankful that I was wearing my Wiley X eye protection this weekend when I was reloading some .223 rounds. My press detonated nearly 100 small rifle primers. Shown here is the magazine feed tube. Not fun but it could have been much worse. Stay safe!”
When working with progressive reloading presses, you should definitely wear eye protection. Dustin’s chain detonation experience proves that — without a doubt. Remember you only have one set of eyes!
RCBS APS Strips — Alternative to Primer Tubes When you stack a column of primers in a single metal tube, you’re asking for trouble. As Dustin Ellermann learned, when one primer fires, the entire column can follow suit in a chain detonation. Thankfully, you do have options when it comes to primer feeding on a progressive press. RCBS developed an innovative, smart system with primers in horizontal plastic strips. Instead of being stored in a vertical tube, primers are placed in flat, plastic “APS” strips, with a ring of plastic separating each primer. Moving horizontally, primers are never stacked, so the chance of a chain detonation is reduced dramatically. The re-usable APS strips are color-coded for different primer types. You can buy CCI “pre-loaded” primer strips, or you can insert any brand of primers into strips using an RCBS strip-loader tool.
RCBS APS Strip Priming System This video shows how to use APS primer strips wiht a bench-mounted priming system.
AccurateShooter.com Editor Uses Strip Primers
This Editor owns an RCBS Pro-2000 progressive press. The RCBS strip-priming system was one key reason I selected the RCBS Pro-2000 over similar-priced progressives from Dillon and Hornady. I believe the strip primer system is safer, more positive, and easier to use. Before I purchased my RCBS progressive, I “road-tested” the competition. I loaded hundreds of rounds on each of four different progressives: Dillon 550B, Dillon 650, Hornady Lock-N-Load, and RCBS 2000. I was concerned about the primer feed tubes on the Dillons, and I found the RCBS rotary powder measure was much more precise (and easier to adjust) than the sliding bar system on the Dillon machines. The RCBS priming system was definitely more fool-proof than the system on the Hornady press (a first-generation L-N-L that had issues with primer feeding). After “test-driving” blue, red, and green brand progressives extensively, I settled on the RCBS Pro-2000. A decade later, I still think I made the right choice. I like the APS strips for big jobs, and I can also use them in the RCBS hand-priming tool (shown below). With the strips, it’s easy to prime 20 or 40 cases at a time, and then switch to another type of primer for comparison testing.
NOTE: Unfortunately, most of the RCBS APS system tools are no longer in production. But the tools and strips are still available on eBay and many reloading Forums, in some cases “new in box”. This Editor’s APS hand priming tool is still working great after 15 years.
The APS priming system also works with press-mounted priming tool, bench-mounted tool, and APS hand-tool. EdLongRange uses the press-mounted tool: “I also like the APS approach but use the press-mounted unit (saves your hands/wrists — and I haven’t had a need for a progressive press in over 20 years). Loading the primers in the strips is a bit of a PITA but very manageable. As with all tools there is a learning curve.” CLICK HERE for video showing strip-loading tool and press-mounted APS tool. The RCBS press-mounted tool is no longer in production by RCBS, but you can still find it in some stores or on eBay.
Savage Arms offers a series of Shooting Tips in the Savage Blog. Here is a helpful article from Team Savage Shooter Stan Pate. This covers how to ship your rifle safely, and then re-establish zero properly when the gun is reassembled after transport.
Traveling with Firearms — Important Advice
Traveling with firearms can be stressful. You must comply with multiple regulations and then trust your expensive guns to airline baggage handlers. And after arrival you’ll need to put your rifles back together and confirm the zeros. This article offers helpful travel advice from Team Savage shooter Stan Pate. Pate has traveled the globe competing with match rifles. Here he shares his tips for making trips easier on you and your firearms.
Easier Air Travel With Firearms
TSA isn’t nearly as careful with your rifles as you are. Proper storage before sending your firearm up a conveyer belt and into the belly of a plane is critical. Stan Pate spends lots of time each year traveling the skies and has devised a system for keeping his rifle safe when going to and from.
“Never travel with your firearm completely assembled,” Pate cautions. “A fully assembled firearm is much heavier [as a total unit] than one that has been broken-down and stored [in separate sections]. More weight creates more in-the-case movement, which can result in damage. I learned this the hard way years ago. My rifle was actually broken in half when traveling to an international competition. Record your torque settings, use those settings during reassembly and your return to zero should be no problem.”
“Be sure to check on current TSA rules and regulations before travel to be aware of any changes that may effect how you pack your rifles,” says Pate.
Rifle Reassembly and Resetting Zero
The quicker you can reestablish your zero, the quicker you can relax and stop worrying about if your rounds are going to hit their mark during competition. Pate, over the years, has developed a system for rifle reassembly and getting back to zero as quickly as possible. While his torque settings may not be the same as yours, the process can still be used.
“The barreled-action goes back on the stock, and then I tighten all three receiver screws finger tight,” says Pate. “Next, I tighten the front two receiver screws down to 35-inch pounds. The rear receiver screws on this particular rifle likes 15-inch pounds. [Note: Proper torque settings will vary with your action and stock type. Most actions have TWO screws, not three.] Scope attachment comes next, and I follow manufacturer settings when tightening it down. All that’s left to do now is go zero your rifle.”
This video explains an efficient method to Re-Zero your rifles
There is an excellent article about primers on the Shooting Times website. We strongly recommend you read Mysteries And Misconceptions Of The All-Important Primer, written by Allan Jones. Mr. Jones is a bona fide expert — he served as the manager of technical publications for CCI Ammunition and Speer Bullets and Jones authored three editions of the Speer Reloading Manual.
This authoritative Shooting Times article explains the fine points of primer design and construction. Jones also reveals some little-known facts about primers and he corrects common misconceptions. Here are some highlights from the article:
Size Matters
Useful Trivia — even though Small Rifle and Small Pistol primer pockets share the same depth specification, Large Rifle and Large Pistol primers do not. The standard pocket for a Large Pistol primer is somewhat shallower than its Large Rifle counterpart, specifically, 0.008 to 0.009 inch less.
Magnum Primers
There are two ways to make a Magnum primer — either use more of the standard chemical mix to provide a longer-burning flame or change the mix to one with more aggressive burn characteristics. Prior to 1989, CCI used the first option in Magnum Rifle primers. After that, we switched to a mix optimized for spherical propellants that produced a 24% increase in flame temperature and a 16% boost in gas volume.
Foiled Again
Most component primers have a little disk of paper between the anvil and the priming mix. It is called “foil paper” not because it’s made of foil but because it replaces the true metal foil used to seal early percussion caps. The reason this little disk exists is strictly a manufacturing convenience. Wet primer pellets are smaller than the inside diameter of the cup when inserted and must be compacted to achieve their proper diameter and height. Without the foil paper, the wet mix would stick to the compaction pins and jam up the assembly process.
Primer Functionality and Primer Types Compared
This video looks at a variety of primer types from multiple manufacturers, foreign and domestic. The video explains the basics of how primers function, and then explains the key characteristics of standard primers, magnum primers, and mil-spec primers (designed for semi-auto rifles).
Many novice hand-loaders believe that neck bushing Inside Diameter (ID) size is the only important factor in neck tension. In fact, many different things will influence the grip on your bullet and its ability to release from the case neck. To learn more about neck tension and “case grip”, take the time to read this article carefully. We bet you’ll gain knowledge that will let you load more accurate ammo, with better ES/SD.
Editor: Guys, this is a VERY important article. You really should read it over carefully, twice. Variations in the force required to release a bullet can significantly affect accuracy and ES/SD. You really need to know how the grip on bullet can be altered by many different factors.
Neck Tension (i.e. Grip on Bullets) Is a Complex Phenomenon
While we certainly have considerable control over neck tension by using tighter or looser bushings (with smaller or bigger Inside Diameters), bushing size is only one factor at work. It’s important to understand the multiple factors that can increase or decrease the resistance to bullet release. Think in terms of overall brass-on-bullet “grip” instead of just bushing size (or the internal neck diameter in non-bushing full-length sizing dies).
Bullet grip is affected by many things, such as:
1. Neck-wall thickness.
2. Amount of bullet bearing surface (shank) in the neck.
3. Surface condition inside of neck (residual carbon can act as a lubricant; ultrasonic cleaning makes necks “grabby”).
4. Length of neck (e.g. 6mmBR neck vs. 6mm Dasher).
5. Whether or not the bullets have an anti-friction coating.
6. The springiness of the brass (which is related to degree of work-hardening; number of firings etc.)
7. The bullet jacket material.
8. The outside diameter of the bullet and whether it has a pressure ridge.
9. Time duration between bullet seating and firing (necks can stiffen with time).
10. How often the brass is annealed.
11. Amount (length) of neck sized (e.g. you can size only half the neck).
12. Interior diameter of bushing, or neck section of non-bushing die. – and there are others…
One needs to understand that bushing size isn’t the beginning and end of neck tension questions, because, even if bushing size is held constant, the amount of bullet “grip” can change dramatically as the condition of your brass changes. Bullet “grip” can also change if you alter your seating depth, and it can even change if you ultrasonically clean your cases.
6-time U.S. National Long-Range Champion John Whidden adds: “Our tests show us that the condition of the necks in regards to lubed or not, carbon inside or not, squeaky clean or not, etc., matter even more than the size of the bushing used. An ultrasonically cleaned or brand new dry case neck make for some quite high seating force.”
In our Shooters’ Forum a reader asked: “How much neck tension should I use?” This prompted a lengthy Forum discussion in which other Forum members recommended a specific number based on their experience, such as .001″, .002″, or .003″. These numbers, as commonly used, correspond to the difference between case-neck OD after sizing and the neck OD of a loaded round, with bullet in place. In other words, the numbers refer to the nominal amount of interference fit (after sizing).
While these commonly-used “tension numbers” (of .001″, .002″ etc.) can be useful as starting points, neck tension is actually a fairly complex subject. The actual amount of “grip” on the bullet is a function of many factors, of which neck-OD reduction during sizing is just one. Understanding these many factors will help you maintain consistent neck tension as your brass “evolves” over the course of multiple reloadings.
Seating Depth Changes Can Increase or Decrease Grip on Bullet
You can do this simple experiment. Seat a boat-tail bullet in your sized neck with .150″ of bearing surface (shank) in the neck. Now remove the bullet with an impact hammer. Next, take another identical bullet and seat it with .300″ of bearing surface in another sized case (same bushing size/same nominal tension). You’ll find the deeper-seated bullet is gripped much harder.
Neck-Wall Thickness is Important Too
I have also found that thinner necks, particularly the very thin necks used by many 6mm PPC benchrest shooters, require more sizing to give equivalent “grip”. Again, do your own experiment. Seat a bullet in a case turned to .008″ neckwall thickness and sized down .003″. Now compare that to a case with .014″ neckwall thickness and sized down .0015″. You may find that the bullet in the thin necks actually pulls out easier, though it supposedly has more “neck tension”, if one were to consider bushing size alone.
In practical terms, because thick necks are less elastic than very thin necks, when you turn necks you may need to run tighter bushings to maintain the same amount of actual grip on the bullets (as compared to no-turn brass). Consequently, I suspect the guys using .0015″ “tension” on no-turn brass may be a lot closer to the guys using .003″ “tension” on turned necks than either group may realize.
Toward a Better Definition of Neck Tension
As a convenient short-cut, we tend to describe neck tension by bushing size alone. When a guy says, “I run .002 neck tension”, that normally means he is using a die/bushing that sizes the necks .002″ smaller than a loaded round. Well we know something about his post-sizing neck OD, but do we really have a reliable idea about how much force is required to release his bullets? Maybe not… This use of the term “neck tension” when we are really only describing the amount of neck diameter reduction with a die/bushing is really kind of incomplete.
My point here is that it is overly simplistic to ask, “should I load with .001 tension or .003?” In reality, an .001″ reduction (after springback) on a thick neck might provide MORE “grip” on a deep-seated bullet than an .003″ reduction on a very thin-walled neck holding a bullet with minimal bearing surface in the neck. Bushing ID is something we can easily measure and verify. We use bushing size as a descriptor of neck tension because it is convenient and because the other important factors are hard to quantify. But those factors shouldn’t be ignored if you want to maintain consistent neck tension for optimal accuracy.
Consistency and accuracy — that’s really what this all about isn’t it? We want to find the best neck tension for accuracy, and then maintain that amount of grip-on-bullet over time. To do that you need to look not only at your bushing size, but also at how your brass has changed (work-hardened) with time, and whether other variables (such as the amount of carbon in the neck) have changed. Ultimately, optimal neck tension must be ascertained experimentally. You have to go out and test empirically to see what works, in YOUR rifle, with YOUR bullets and YOUR brass. And you may have to change the nominal tension setting (i.e. bushing size) as your brass work-hardens or IF YOU CHANGE SEATING DEPTHS.
Remember that bushing size alone does not tell us all we need to know about the neck’s true “holding power” on a bullet, or the energy required for bullet release. True bullet grip is a more complicated phenomenon, one that is affected by numerous factors, some of which are very hard to quantify.
Yet another .300 Blackout disaster. Unfortunately, that .300 Blackout cartridge can fit in a .223 Rem chamber. Shooting a .308-caliber bullet in .223 bore is a recipe for disaster.
The .300 AAC Blackout aka “300 BLK”, is a compact 30-caliber cartridge designed to work in AR-15 rifles. It has a shorter cartridge case to accommodate the bigger 30-caliber bullet while still fitting in a standard AR-15 magazine. Unfortunately, that’s the danger. A careless shooter can toss a .300 Blackout cartridge in with .223 Rem rounds without noting. And because the case-head size is the same as the .223 Rem (5.56×45) the rifle’s bolt assembly will happily chamber and fire the .300 BLK round. Problem is, that forces a .308 diameter bullet down an undersized .223-caliber bore. Not good!
This images were provided by Tactical Rifle Shooters on Facebook. The message was clear: “Don’t try to run 300 Blackout in your .223/5.56mm. It won’t end well. The problem is identical rifles and identical magazines but different calibers.”
Image from Accurate Shooter Forum. Cutaway shows the jammed .30-Cal bullet:
For those who MUST have a .300 Blackout, here are some things you can do:
1. Use different colored magazines for .300 Blackout vs. .223 Rem.
2. Fit all your uppers with caliber-labeled ejection port covers.
3. Mark .223 Rem upper handguards with the caliber in bright paint.
4. Mark all .300 BLK Rounds with heavy black marker.
Comments by Folks Who Viewed these .300 Blackout Disaster Photos:
“The .300 Blackout is simply a badly-designed round. A properly-designed round would have had a feature in the shape that would have prevented cross loading in the first place.” — D. Santiago
“I almost made that mistake… I had a magazine of 300 BLK inserted in my .223/5.56 all night. Fortunately, I never pulled the trigger. Once I realized the mistake, I almost got ill. [After that incident] I no longer own a 300 BLK.” — B. Welch
“Happened to me hog hunting from a helo. Gun exploded in my face.” — B. Hood
“Fire-forming projectiles [is] so wrong in centerfire!” — M. Stres
“Had some dude come into the store the other day wanting .300 Blackout ammo to shoot in his 5.56 AR. It took 15 minutes of explaining for him to understand you got to have a .300 Blackout Upper!” — R. Williams
A while back, our friend Bill Marr of Rifleshooter.com conducted a fascinating 6mm Creedmoor barrel cut-down test that reveals how velocity changes with barrel length. This time Bill started with a 24″ Proof Research stainless steel barrel on a Howa action. Bill says this was a well-used barrel, with over 1800 rounds through it. So, the velocities might be a bit different than a new barrel of similar length. Bill cut the barrel down in one-inch increments. Here are some results from the test:
For this latest test, Rifleshooter cut the barrel in one-inch increments from 24″ to 16.1″ (just over legal minimum). Velocities were measured with a MagnetoSpeed V3 chronograph mounted on arm attached to the stock. This allowed the chrono to be adjusted inwards as the barrel was cut shorter, inch by inch.
For the 6mm Creedmoor cartridge, Bill loaded Hornady 108gr ELD Match bullets over 41.5 grains of Hodgdon H4350 with CCI 200 primers in new Starline brass.
The results were interesting to say the least. Bill reports: “Muzzle velocities ranged from 2,893 ft/sec at 24″ to 2,598 ft/sec at 16″ for a decrease in muzzle velocity of 295 ft/sec. Muzzle velocity changes per inch of barrel length ranged from 6 ft/sec per inch between 20 and 19 inches to 63 ft/sec per inch between 19 and 18 inches. Average velocity change per inch of barrel length was 37.9 ft/sec.”
Bill concludes: “An average drop of 37.9 ft/sec/inch of barrel is fairly significant and is what would be expected with a fast moving 6mm cartridge like the 6mm Creedmoor. While I’m used to seeing 6mm Creedmoors with slightly longer barrel lengths than 24″, when coupled with a sound suppressor the additional length can make moving the rifle quickly more difficult.
I’d suggest staying with longer barrel lengths wherever possible with this cartridge. At shorter lengths, it does give up more performance than its big brother the 6.5 Creedmoor.”
More 6mm Creedmoor Velocity Data from 2017 Cut-Down Test
If you’re curious about 6mm Creedmoor velocities at longer barrel lengths, back in 2017 Rifleshooter completed a 6mm Creedmoor barrel cut-down test from 31 inches all the way down to 17 inches. The test included four bullet types from 95 grains to 110 grains. With the 110gr Sierra MK, velocity at 31″ was an impressive 3110 fps. Surprisingly the velocity didn’t decrease that much for the first few inches. Even at 26″ (a five-inch reduction), measured velocity with the 110s was 3073 fps, a loss of 7.4 fps per inch on average. With a barrel shortened all the way to 20″ however, velocity had dropped down to 2949 fps, a significant (161 fps) loss. CLICK HERE for complete results from that 31″-17″ Barrel Cut-Down Test.
If you have been waiting to purchase a chronograph… now is a great time to buy. You can get the reasonably-priced MagnetoSpeed Sporter for $249.00. You can set up this device in a few minutes, and you never have to go downrange to fiddle with a tripod or fuss with wires. The MagnetoSpeed Sporter is simple and effective — a no-hassle solution.
See MagnetoSpeed Sporter Chronograph Features Reviewed in Video
We’re impressed by the Sporter chrono, as are other shooters — this unit is very popular. Like the MagnetoSpeed V3, the Sporter faithfully records shots, even in complete darkness. Shot strings are recorded digitally and can be transferred to a smart phone via MagnetoSpeed’s XFR accessory (and Apps).
The Magnetospeed Sporter offers most of the features of the more expensive models (see chart below for details) and has a updated sensor. MagnetoSpeed says the Sporter is “Ideal for contoured rifle barrels (sporter barrels) and long-barreled revolvers.” The Sporter Chronograph Kit (shown above) includes: Bayonet Sensor, 3.5 foot Data Cable, Remote Display (with Battery), Strap with thumb nut, Two V-block spacers, and compact storage box.
Q: Will the Sporter Chrono work with thicker barrel (i.e. greater than 1″ diameter)?
A: The manufacturer recommends the $449.00 V3 model for thicker barrels. But, wink-wink, if you have a 1.25″ barrel you can get this to work, based on what we’ve seen.. If you have a really fat barrel (up to 2.0″ diameter), get the V3. Magnetospeed also says the V3 is needed for airguns, shotguns, and muzzleloaders.
Click Image for Full-Screen Photo
The Sporter Chrono attaches quickly and easily. It has a 3.5-foot-long cord, and will work with Muzzle Brakes and Flash-hiders up to 2.7″ long.
The Tactical Rifle Shooters Facebook Group recently showcased tools used to measure case headspace before and after “bumping” the shoulder. After a case is fired, hand-loaders who full-length size their cases will typically bump the shoulders back anywhere from .001″ to .0035″, depending on the rifle and application. With our 6mmBR and Dasher cases we like about .0015″ bump.
You want the amount of case sizing and bump to be the same for all your brass. To ensure uniformity, it makes sense to measure your cases before and after the FL sizing process. When we have time, we check every case. Other folks will simply check the first 3-4 cases coming out of the FL sizing die to ensure the FL die setting is correct and delivering desired headspace/bump.
1. Whidden Gunworks Shoulder Bump Gauge
There are a variety of tools that can be used to measure shoulder bump. Our favorite is a special cartridge-specific bushing made by Whidden Gunworks. The Whidden Shoulder Bump Gauge enables you to adjust your sizing die to the desired measurement. The bump gauge is attached to your calipers with a set screw and determines the measurement from the base to the shoulder of the case. The photo below, from Tactical Rifle Shooters, shows the Whidden Bump Gauge for the .375 CheyTac cartridge.
2. Dave Manson Vertical Comparator with Dial Read-Out
Dave Manson states: “This tool was designed to make life easier for the advanced shooter and re-loader by allowing precise measurement of ammunition, case, and chamber headspace. With this information, the re-loader will be able to fine-tune clearances and fits between his ammunition and chamber, with resultant improvements in accuracy and case life.” The functions of the Manson Comparator are:
1. Measure headspace of factory or reloaded ammunition
2. Quantify chamber headspace by measuring headspace of a fired case
3. Ensure minimal shoulder set-back when setting up re-loading dies
4. Compare base-to-ogive length to ensure consistent bullet-to-rifling relationship.
Hornady’s Lock-N-Load Headspace Comparator system is easy-to-use and handy. You can get a kit with Red bushing-holder body and 5 bushings for $43.43 at Midsouth. Hornady explains: “The Lock-N-Load® Headspace Comparator… gauge measures variations in brass before and after firing or re-sizing. It allows for headspace comparison between fire-formed brass and re-sized brass.” IMPORTANT: Hornady states: “To determine the proper bushing diameter for your cartridge, simply add the neck diameter and the shoulder diameter and divide that number by two. Use the bushing closest to that number.” Hornady offers five: .330″, .350″, .375″, .400″, and .420″.
One tip — We have found the Hornady gauges may vary a little from unit to unit even with the same nominal size. If you have more than one gauge for the same cartridge, test each on your brass — you may then note a slight difference in your bump measurements. Mark one and use that consistently. There is also an Anvil Base Kit that mounts to the opposite blade on the caliper. This provides a more stable surface for the base of your case.
4. L.E. Wilson Case Gage Depth Micrometer
If you are looking for precise “bump” measurements without having to mess with calipers and clamp-on gauge blocks, you may want to consider the L.E. Wilson Case Gage Depth Micrometer (currently $130.00). This takes very precise, repeatable measurements, but you need to know your starting point. The manufacturer explains: “Every reloader should know exactly how much your Full Length Sizing Die is pushing back the shoulder. With the NEW Case Gage Depth Micrometer you can do just that! It has never been easier to measure you cases headspace before and after sizing. The Depth Mic allows you to slip the micrometer perfectly over the top of the Gage with your case inserted into the Gage and take a measurement. Micrometer has graduations of .001″. The Case Gage Depth Micrometer is set to a zero of .100″ on the scale at our factory. Because of differences in ‘feel’ and temperature, we include a the Gage Block for you to test Zero and to adjust if necessary.”
5. Pistol Brass Case DIY Bump Gauge
Last is a “field expedient” set-up if you do not have any of the comparator tools shown above. A sized .45 ACP case (or other suitable pistol case) can be used to measure shoulder bump. The mouth of the pistol case sits on the shoulder of your rifle cartridge brass.
Make sure the .45 ACP case is trimmed square and that it is round. We recommend you first run it through an expander, then size it, trim it and chamfer. Next, take the .45 ACP case and slip it over the neck of a fired, unsized rifle case with the primer removed. Align the two cases between the jaws of your calipers and note the length from rim to rim (See left photo below).
OK, now you have the length for a fired rifle case BEFORE sizing. Next, take a full-length sized rifle case (without primer) and do the same thing, placing the .45 ACP case over the neck of the FL-sized case (Right Photo). The difference between the two numbers is the amount of “bump” or set-back you are applying to the shoulder. Here the difference is .0015″. The amount of bump you need varies with your chamber and your load, but .0015-.002″ is a good initial setting.
Assembly Diagram: Here are all the components of the target frame. The overall maximum assembled dimensions are roughly 26″ wide, 41″ deep, and 66″ tall (the cardboard is 2 x 3 feet).
One of the easiest ways to build a portable target stand is to use PVC pipe and connectors. Utah .308 Shooter “Cheese” has created a simple yet sturdy target frame, and he’s shared his design so you can build a similar frame easily and at low cost. The components are wood furring strips, 2″-diameter PVC pipes (and connections), and a 2’x3′ sheet of cardboard. The PVC base can be glued together, or, for easier transport and storage, you can leave some or all of the connections free. “Cheese” tells us: “I didn’t glue any of it together so I could disassemble it, shove it in a bag and take it anywhere.”
“All the parts are just pushed together and not glued. That way I can break it down and carry it all in a bag. Also, if a buddy (not me!) happens to shoot the stand, I can easily replace just the damaged piece. The last 6 inches of the furring strips are wittled-down a bit so they can be pushed into the upright pipes with a little friction. The cardboard is 2 x 3 feet, and I use a staple gun to attach it to the furring strips. Then I just staple the target onto the cardboard and go at it.
Of course you can modify the dimensions as desired. I chose the black ABS pipe over white PVC simply for cost — black ABS is a little cheaper. You can also glue some or all of the parts together, it’ll just be larger for transporting. In windy conditions, the thing likes to come apart. Duct tape might work well.
For weight, I thought about filling the two end pipes with sand and gluing test caps on each of their ends. The test caps still allow the pipes to slip into the elbows.”
Add Anchors or Internal Weight for Stability
On a very windy day, a PVC stand can shake or even topple over. There are a couple solutions to this. Some people fill the PVC pipe sections with sand to add weight, or you can put short sections of Re-BAR inside the long legs. One GlockTalk forum member noted: “I built [a frame] almost identical to this. I also take four pieces of wire coathanger bent into an inverted “U” shape to anchor the frame to the ground. It is so light that wind will knock the stand over [without anchors].”
You can find photos of a similar home-made PVC target stand (with a slightly different rear section) on the Box of Truth website. This also employs a PVC tubing base with wood uprights. We’ve also seen all-PVC target stands, but we’ve found that it is easier to attach the cardboard to wood strips than to PVC pipe. Also, if the upper section is wood, you can fit different height targets, while using the same base.