February 1st, 2015

Over-Shooting the Berm — When a Mere 5 Degrees Can Be Deadly

In our Shooters’ Forum, there was an discussion about a range that was threatened with closure because rifle over-shoots were hitting a farm building over two miles from the firing line. One reader was skeptical of this, asking “how’s that possible — were these guys aiming at the stars?” Actually, you may be surprised. It doesn’t take much up-angle on a rifle to have a bullet land miles down-range. That’s why it’s so important that hunters and target shooters always orient their barrels in a safe direction (and angle). Shooters may not realize how much a small tilt of the barrel (above horizontal) can alter a bullet’s trajectory.

How many degrees of muzzle elevation do you think it would take to hit a barn at 3000 yards? Ten Degrees? Twenty Degrees? Actually the answer is much less — for a typical hunting cartridge, five to seven degrees of up-angle on the rifle is enough to create a trajectory that will have your bullet impacting at 3000 yards — that’s 1.7 miles away!

Five degrees isn’t much at all. Look at the diagram below. The angle actually displayed for the up-tilted rifle is a true 5.07 degrees (above horizontal). Using JBM Ballistics, we calculated 5.07° as the angle that would produce a 3000-yard impact with a 185gr .30-caliber bullet launched at 2850 fps MV. That would be a moderate “book load” for a .300 Win Mag deer rifle.

Gun Angle long range

Here’s how we derived the angle value. Using Litz-derived BCs for a 185gr Berger Hunting VLD launched at 2850 fps, the drop at 3000 yards is 304.1 MOA (Minutes of Angle), assuming a 100-yard zero. This was calculated using a G7 BC with the JBM Ballistics Program. There are 60 MOA for each 1 degree of Angle. Thus, 304.1 MOA equals 5.068 degrees. So, that means that if you tilt up your muzzle just slightly over five degrees, your 185gr bullet (2850 fps MV) will impact 3000 yards down-range.

Gun Angle long range

Figuring Trajectories with Different Bullets and MVs
If the bullet travels slower, or if you shoot a bullet with a lower BC, the angle elevation required for a 3000-yard impact goes up, but the principle is the same. Let’s say you have a 168gr HPBT MatchKing launched at 2750 fps MV from a .308 Winchester. (That’s a typical tactical load.) With a 100-yard zero, the total drop is 440.1 MOA, or 7.335 degrees. That’s more up-tilt than our example above, but seven degrees is still not that much, when you consider how a rifle might be handled during a negligent discharge. Think about a hunter getting into position for a prone shot. If careless, he could easily touch off the trigger with a muzzle up-angle of 10 degrees or more. Even when shooting from the bench, there is the possibility of discharging a rifle before the gun is leveled, sending the shot over the berm and, potentially, thousands of yards down-range.

Hopefully this article has shown folks that a very small amount of barrel elevation can make a huge difference in your bullet’s trajectory, and where it eventually lands. Nobody wants to put holes in a distant neighbor’s house, or worse yet, have the shot cause injury. Let’s go back to our original example of a 185gr bullet with a MV of 2850 fps. According to JBM, this projectile will still be traveling 687 fps at 3000 yards, with 193.7 ft/lbs of retained energy at that distance. That’s more than enough energy to be deadly.

Permalink Shooting Skills, Tech Tip 6 Comments »
January 25th, 2015

Cortina’s Corner: Installing Jewell Trigger in Panda F-Class Action

Eric Cortina Lapua Jewell Trigger Panda Stolle Action Kelbly Kelbly's

In the video below, Forum member Eric Cortina shows how to install a Jewell Benchrest trigger into a Kelbly F-Class Panda action. You could follow the same simple procedure to install a Jewell in a standard Panda action. Kelbly’s sell both standard and long versions of the F-Class Panda action. Both versions feature integral recoil lugs in the front.

To see more detail in this “how-to” video, you can zoom it to full-screen size. Simply click the full-screen icon (4-cornered frame) just to the right of the YouTube logo in the lower right.

Eric Cortina Lapua Jewell Trigger Panda Stolle Action Kelbly Kelbly's

Eric Cortina Lapua Jewell Trigger Panda Stolle Action Kelbly Kelbly's

Permalink Gunsmithing, Tech Tip 1 Comment »
January 21st, 2015

Preacher Builds Stock the Old-Fashioned Way — with Hand Tools

Forum member Preacher recently crafted a nice varmint rifle for fellow Forum member Dave 0. (aka “Waskawood”). But rather than buy an off-the-shelf stock, Preacher crafted this stock all by hand, starting from a laminated blank panel. He calls this stock project his “Axe Job”.

CLICK for Full-size Photo
hand made axe job stock 17 VMA varmint

This stock is being used on a prairie dog rifle, chambered for a 17-caliber wildcat, the 17 VHA, which is based on an H&K 4.6x30mm parent case. With about nine grains of 300 MP pistol powder, the 17 VHA drives 20-grainers at about 3850 fps. (SEE details at end of article).

The ‘Axe Job’

Report by Preacher
I like carving with the laminates because all the lines are right there in front of my eyes, so it’s easy to follow along and get it just right, until it’s pleasing to the eye. I never use a template, I just keep checking the lines as I go along. I have all the needed equipment to power build one of these, but I really enjoy the time spent on the hand work. From start to completely ready-to-install, I’ll have about six (6) weeks into one of these stock projects. A lot of that is drying time for the clear coats.

A little work with the hand axe, after a trip through the band saw…
hand made axe job stock 17 VMA varmint

The majority of the laminated blank panels I use for my gunstocks are purchased directly from Cousineau Wood Products or from Rutply.com. You have to buy at least four full panels at a time, all the same color, but that will yield eight (8) stocks. Seems like I have a little over $150.00 in a blank large enough to start making a full-sized, benchrest-style stock.

A little work with a chisel…
hand made axe job stock 17 VMA varmint

A little work with a rasp. (Before I was rich and famous and could afford really good rasps, I used a good old horse shoe rasp.)
hand made axe job stock 17 VMA varmint

A little more work with the chisel…
hand made axe job stock 17 VMA varmint

Preacher’s Advice on Carving Your Own Stock
The one main advantage of being older that dirt, and tormented with MS the past 40 years, is lots of free time to enjoy what ever I can do these days, as long as I can set down to do it, and I can make a lot of wood chips setting down.

Any one can do this if they have the time to devote to it. All it takes is time and a good eye for details. I made a lot of firewood over the years, until I got the hang of it. Most all those problems were inletting, and screw hole spacing. Get those right the first time and you’re on your way….

A little more work with the rasp…
hand made axe job stock 17 VMA varmint

A few coats of Auto clear has it about buttoned up…
hand made axe job stock 17 VMA varmint

Micro 17 VHA Wildcat
Here’s the finished rifle built by Preacher for Dave, using the ‘Axe Job’ stock. Dave tells us: “Preacher chambered the rifle for the 17 VHA, a wildcat based on the H&K 4.6x30mm MP7 PDW case necked down to 17 caliber. There are numerous articles in the Varmint Hunter’s Magazine about it. This efficient little round shoots 20gr ballistic tips at 3850+ fps. That’s not too shabby for ‘nine point something’ grains of pistol powder.”

“My intentions for my 17 VHA rifle are to plop down in the middle of a PD town with my swivel bench and shoot prairie dogs. I also thought it would be a nice platform to test the accuracy of the cartridge. If I like the little round as well as I think, I plan to build a more practical rifle that I can carry. I really want to thank Preacher for his patience with me through this project, as it was my first custom build.”

hand made axe job stock 17 VMA varmint

Permalink Gunsmithing, Tech Tip 5 Comments »
January 17th, 2015

Rifle Barrel Cleaning 101 — The Criterion Way

Editor: This article appears on the Criterion Barrels website. It provides good, conservative advice about barrel cleaning. Understand that cleaning methods may need to be adapted to fit the amount and type of fouling (and the particular barrel). In general, we do try to minimize brushing, and we follow the procedures Criterion recommends respecting the crown/muzzle. We have also had very good success using wet patches followed by Wipe-Out bore foam. Along with the practices outlined by Criterion below, you may want to try Wipe-Out foam. Just be sure to use a fitted cleaning rod bore guide, to keep foam out of the action recesses and trigger assembly.

Criterion Barrels Cleaning Clean Solvent rod guide Hoppes Wipe-Out

What is the Best Way to Clean a Rifle Barrel?

We are asked this question quite frequently alongside requests for recommended break-in procedures. Improper barrel cleaning methods can damage or destroy a barrel, leading to diminished accuracy or even cause a catastrophic failure. When it comes to barrel maintenance, there are a number of useful techniques that we have not listed. Some techniques may work better with different barrel types. This series of recommendations is designed to incorporate a number of methods that the Criterion Barrels staff has used successfully both in the shop and on their personal rifles. Please feel free to to list your own recommendations in the below comments section.

We recommend the use of the following components during rifle cleaning:

• Cloth patches (sized for the appropriate caliber)
• Brass jag sized properly for your bore
• One-piece coated cleaning rod
• General bore cleaner/solvent (Example: Hoppes #9)
• Copper solvent of your choosing (Example: Sweets/KG 12)
• Fitted cleaning rod bore guide
• Plastic AP brush or toothbrush
• Q-Tips
• Plastic dental picks
• CLP or rust preventative type cleaner

There are a number of schools of thought relating to the frequency in which a barrel should be cleaned. At minimum we recommend cleaning a barrel after each shooting session to remove condensation, copper, and carbon build-up. Condensation is the greatest immediate threat, as it can cause the barrel to rust while the rifle sits in storage. Copper and carbon build-up may negatively impact future barrel performance, increasing the possibility of a failure in feed or function. Fouling should be removed whenever possible.

The below tips will help limit the wear of different parts of your barrel during routine maintenance, helping extend the life of the barrel and improving its performance.

The Crown
The crown is the portion of the barrel where the bullet loses contact with the lands and grooves and proceeds to exit the firearm. The area most critical to accuracy potential is the angle where the bullet last touches the bore of the barrel.

Avoid damage to this area by using a plastic toothbrush and CLP type cleaner to scrub the crown from the exterior of the barrel. Even the most minimal variation in wear to the crown will negatively impact barrel performance, so be careful to avoid nicking or wearing away this part of the barrel.

Reducing Cleaning Rod Wear to the Crown
When running a patch through the barrel, place the muzzle about a ¼” from a hard surface that runs flat at a perpendicular angle to the cleaning rod’s direction of travel, like a wall or the edge of a work bench (pictured). When the jag impacts the hard surface, retract the cleaning rod and remove the patch.

By withdrawing the jag prior to its exit from the barrel, you are limiting the possibility of the brass dragging upon the crown if the rod is at all bent or misaligned. The soft cloth patch will continue to serve as the point of contact between the jag and the barrel, minimizing potential wear.

If possible, insert the rod through the chamber, pushing it forward toward the muzzle. Some rifles, such as the M1 Garand or M14, will require you to insert the cleaning rod through the muzzle. In these situations the use of a cleaning rod guide is recommended to limit the friction placed upon the crown.

Avoid using cleaning rod segments for scraping carbon from the recessed muzzle of an AR-15 barrel. We used this trick in the Marine Corps to impress the armorers and NCO’s with the cleanliness of our muzzles, but it likely played a significant role in reducing the service life of the rifle barrel in question.

Use a Q-Tip soaked in solvent to remove any copper or carbon residue from the recessed muzzle of an AR-15 barrel. A little bit of remaining carbon on the face of the muzzle will not negatively affect bullet travel so long as the crown edge remains consistent around the circumference of the bore.

The Lands and Grooves
This portion of the barrel may experience reduced efficiency due to copper fouling and cleaning rod damage. If copper fouling takes place during the initial break-in of the rifle, make sure to check our barrel break-in article.

For regular maintenance we suggest using a single piece coated cleaning rod rather than the traditional segmented rod or bore snake. While segmented rods and bore snakes may be convenient for field use, the corners between the segments may bow out and catch on the lands, scraping along the length of the rifling. Residual grit and particles from expended cartridges may also get caught between segments, resulting in an abrasive surface working its way down the length of the barrel. Most bore snakes will remove significant amounts of carbon fouling, but may fall short in the removal residual carbon buildup and copper fouling during deep cleaning. Good rods can be sourced from multiple manufacturers, but we have found good results using both Pro-Shot and Dewey brand products.

General cleaning requires the use of patches rather than nylon or brass bore brushes. Brass brushes may be required when aggressive cleaning is required, but can lead to unnecessary wear on the barrel if used frequently. This is not due to the nature of the soft brushes themselves, but from the abrasive particles of grit that become embedded in the material that is being run repeatedly through the bore. We recommend the use of bore guides when cleaning from both the muzzle and breech. These bore guides will help serve to protect the crown and throat from cleaning rod damage.

If significant resistance develops while running the cleaning rod through the bore, no attempt should be made to force it in further. Back the rod out and inspect the barrel to determine the cause of the resistance. The jag may be pushing between a bore obstruction and the rifling, digging a divot into the barrel before pushing the obstruction back through the muzzle. One way to minimize the risk of a stuck rod is by utilizing a slightly smaller patch during the initial push.

The process of cleaning the length of the rifling is relatively straightforward:

1. Check to make sure the rifle is safely unloaded.
2. Carry out any necessary disassembly procedures prior to cleaning.
3. Remove bolt (if possible) and insert fitted cleaning rod bore guide in action.
4. Soak a patch in bore solvent (similar to Hoppes #9).
5. Center and affix the patch on the brass jag, inserting it into the chamber end of the barrel. A misaligned patch may cause the jag to damage the lands of the rifling, so make sure the patch is centered on the jag.
6. Run the patch the full length of the barrel, retracting it upon reaching the end of the muzzle.
7. Let the solvent sit for a minute.
8. Continue to run patches through the bore until carbon residue is minimized.
9. Run a dry patch through the bore to ensure carbon residue has been removed.
10. Soak a patch in copper solvent (Sweet’s or KG-12).
11. Run the patch through the bore, leaving it to sit for 3-5 minutes (do not let solvent sit for more than 15 minutes.*)
12. Repeat this process until no blue residue remains on the patches.
13. Run a patch of Hoppes #9 and a dry patch through the bore to neutralize the copper solvent.
14. Inspect the barrel prior to reassembling the rifle, verifying that no bore obstructions remain.

*Please note that some ammonia-based copper solvents may prove to be corrosive if left sitting in the barrel for an extended period of time. It is essential that these solvents be removed within 15 minutes to avoid ruining the bore.

The Chamber
Proper cleaning of the chamber is a critical component of a general cleaning procedure. Carbon rings can build up near the neck and throat of the chamber wall, leading to feeding malfunctions and pressure spikes inside the chamber.

The chamber can be the trickiest part of the barrel to effectively clean, due to its fluctuation in size and the awkward ergonomics often required to remove carbon residue. Numerous chamber specific devices have been created to address this problem, and while some should be avoided (steel chamber brushes), others can be used to great effect (cleaning stars and plastic dental picks). The simplest approach to cleaning a chamber is to apply solvent to a couple patches, and use the cleaning rod to spin the wadded up patches inside the confines of the chamber. This should aid in removing any excess carbon. A Q-Tip can be used to reach portions of the chamber unreached by patches.

The Barrel Exterior
While the condition of the crown, rifling, and chamber are essential to firearm performance, the finish of the exterior should also be cleaned after handling. Condensation, humidity, direct water contact, and salt residue from skin contact can cause rust or corrosion. An application of anti-corrosion products is recommended when placing a firearm into deep storage for an extended period of time. [Editor: AccurateShooter.com recommends Corrosion-X or Eezox, but other products work well too.]

Finding Cleaning Components
While most cleaning components can be found at your local gun shop, some specialty items may need to be sourced through online retailers such as Brownell’s. Criterion utilizes both Dewey and Pro-Shot brand cleaning components during our day-to-day operations.

Do you have any rifle cleaning tips or tricks not mentioned in the above article? We’d love to hear about them. You can post your comments below.

Permalink - Articles, Tech Tip 2 Comments »
January 13th, 2015

Using the Giraud Power Trimmer — Smart Video from Erik Cortina

Forum member Erik Cortina recently launched his own YouTube Channel dedicated to precision reloading and accurizing. Erik’s videos demonstrate the proper use of specialized reloading tools and provide helpful hints. Erik’s latest video is about the “mother of all brass trimmers”, the Giraud powered case trimmer. Erik says: “It you do volume reloading… this is the only trimmer to get. It not only trims to length but it also chamfers your case mouth inside and out.” In his video, Erik offers some very clever and useful tips that will help you get the most from your Giraud.

The Giraud trimmer is very precise. When set up correctly, it can trim brass with amazing consistency. In the video, Erik trims 5 pieces of brass in 15 seconds (6:32 mark). He then measures all five with precision calipers (7:00-8:08). All lengths are exact within .0005 (half a thousandth). Erik notes that the Giraud trimmer indexes off the case shoulder. As long as you have fire-formed brass with consistent base-to-shoulder dimensions, you should get very consistent trim lengths.

The secret to the system is a 3-way cutting head. This cutter can be swapped in and out in a couple minutes with wrenches provided with the kit. Erik has three different heads; one each for 6.5mm, 7mm, and .30 caliber. The video shows how to adjust the cutting heads to match caliber diameter (and to get the desired amount of inside/outside chamfer).

This is a manufacturer’s photo showing an older model.
Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

To trim and chamfer cases, you simply insert them nose-first into the cartridge-specific case-holder. Erick offers a smart tip — He uses a die locking ring to position the cartridge holder (3:15). This can be locked in place. Erik says die locking rings work much better than the hex-nuts provided by Giraud (with the hex-nut, one must re-set cut length each time you change case-holders.)

Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

The Giraud can be used in either horizontal or vertical modes. Erik prefers to have the trimmer aligned vertically, allowing him to push cases down on the trimmer head. But the trimming unit has twin sets of rubber feet, allowing horizontal or vertical orientation.

Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

Improved Case-Holder Made with Chamber Reamer:
For his .284 Shehane, Erik had to create his own case-holder (Giraud does not make one for that wildcat cartridge). Erik used his chamber reamer. To his surprise, Erik found that the brass was easier to trim in the custom case holder (compared to the Giraud-made spring-loaded holders). With a perfect fit, trimming and case extraction went more smoothly and the process was easier on his hands. (See 9:00-10:00). Based on Erik’s experience, you may want to create your own custom case-holder.

Trim Bullet Meplats Also
With a special bullet-holder fitting and meplat cutter head, the Giraud power trimmer can be used to trim bullet meplats. Trimming meplats can help make the Ballistic Coefficents of a batch of bullets more consistent. Uniforming meplats is also often done as a first step in the process of “tipping” bullets to improve BC.

Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

Giraud Power Trimmer

Permalink - Videos, Reloading, Tech Tip 7 Comments »
January 13th, 2015

Calculate Barrel Weight with FREE Software from Dan Lilja

Dan Lilja Rifle BarrelsAre you re-barreling a match rifle and need to know if you will still make weight? Or perhaps you want to select the right contour to hit an optimal carry weight for a new varmint rifle? Dan Lilja offers FREE software that will calculate barrel weight for straight contour, straight taper, and radius-tapered barrels. Dan’s software even calculates how fluting alters barrel weight.

For general info on barrel weight calculation for straight and straight tapers, read this article on Lilja’s website. Click HERE for another article explaining weight calculation with barrels that have a radiused (curved) contour section.

Here are the free software programs offered by Dan Lilja. Right click and “Save As”:

Straight Contour (.exe file) | Straight Contour (Excel file) | Contoured Barrels with Radius (Excel file)

Dan Lilja Barrel Contour diagram

Permalink Gunsmithing, Tech Tip 2 Comments »
January 3rd, 2015

How to Remove a Cartridge Case Stuck in a Die

To err is human… Sooner or later you’ll probably get a case stuck in a die. This “fix-it” article, which originally appeared in the Western Powders Blog, explains the procedure for removing a firmly stuck cartridge case using an RCBS kit. This isn’t rocket science, but you do want to follow the directions carefully, step-by-step. Visit the Western Powders Blog for other helpful Tech Tips.

Western powders, ramshot, norma, accurate

Curing the Stuck Case Blues

stuck72

decapstem72Sticking a case in the sizer die is a rite of passage for the beginning handloader. If you haven’t done it yet, that’s great, but it probably will eventually happen. When it does, fixing the problem requires a bit of ingenuity or a nice little kit like the one we got from RCBS.

The first step is to clear the de-capping pin from the flash hole. Just unscrew the de-capping assembly to move it as far as possible from the primer pocket and flash hole (photo at right). Don’t try to pull it all the way out. It won’t come. Just unscrew it and open as much space as possible inside the case.

Place the die upside down in the padded jaws of a vise and clamp it firmly into place. Using the supplied #7 bit, drill through the primer pocket. Be careful not to go too deeply inside the cartridge once the hole has opened up. It is important to be aware that the de-capping pin and expander ball are still in there and can be damaged by the bit.

Drill and Tap the Stuck Case
taping72drilling72

Once the cartridge head has been drilled, a ¼ – 20 is tap is used to cut threads into the pocket. Brass is relatively soft compared to a hardened tap, so no lube is needed for the tapping process. RCBS says that a drill can be used for this step, but it seems like a bit of overkill in a project of this nature. A wrench (photo above right) makes short work of the project.

RCBS supplies a part they call the “Stuck Case Remover Body” for the next step. If you are a do-it-yourselfer and have the bit and tap, this piece is easily replicated by a length of electrical conduit of the proper diameter and some washers. In either case, this tool provides a standoff for the screw that will do the actual pulling.

pulling72fingers72

With an Allen Wrench, Finish the Job
Run the screw through the standoff and into the tapped case head. With a wrench, tighten the screw which hopefully pulls the case free. Once the case is free, clamp the case in a vice and pull it free of the de-capping pin. There is tension here because the sizing ball is oversized to the neck dimension as part of the sizing process. It doesn’t take much force, but be aware there is still this last little hurdle to clear before you get back to loading. Don’t feel bad, everyone does this. Just use more lube next time!

wholekit72unstuck72

Article find by EdLongrange. We welcome reader submissions.
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January 3rd, 2015

TECH Tip: Fire-Form with Fouler Shots

PPC Fire-formingHere’s a tip for guys who shoot the 6 PPC, 6 Dasher, or other wildcat cartridges that require fire-forming. Use your fouler shots to fire-form new cases. That way your fouler shots do “double-duty” and you get your brass fire-formed without putting extra rounds through your expensive barrel.

This procedure is recommended by Joel Kendrick, the 2004 IBS 600-yard Shooter of the Year. After he cleans his barrel, Joel knows it takes two or three shots to foul in the bore before accuracy returns. When shooting his PPC, Joel uses those fouler shots to fire-form his new brass. Joel explains: “I like to have relatively new brass always ready. By fire-forming a couple cases after each barrel-cleaning during a match, by the end of the weekend I’ve got a dozen or more freshly fire-formed cases to put into the rotation. If you do this with your fouler shots you get your fire-forming accomplished without using up any extra barrel life.”

We thank Joel for this smart suggestion. For those who do not have a dedicated barrel for fire-forming, this should help keep your round-count down. Joe currently works as the Supplier Quality Process Engineer for MMI-TruTec, a company that offers barrel surface coatings that can further extend your barrel life.

Permalink Tech Tip 2 Comments »
December 29th, 2014

Squeeze Play — The Many Factors Involved in Neck Tension

Redding neck bushingsIn our Shooters’ Forum a reader asked: “How much neck tension should I use?” This prompted a 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.

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.

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 significantly, and it can even change if you ultrasonically clean your cases.

Bullet grip is affected by many things, such as:

  • 1. Neck-wall thickness.
  • 2. Amount of 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. 6BR neck vs. 6BRX).
  • 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. The time duration between bullet seating and actual firing (necks can stiffen with time).
  • 10. How often the brass is annealed

— and there are others…

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.

PPC lapua brassNeck-Wall Thickness is Important Too
I have also found that thinner necks, particularly the very thin necks used by many PPC 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.

Permalink Reloading, Tech Tip 2 Comments »
December 28th, 2014

Close Call: Tumbler Catches on Fire in Reloading Room

Electrical Fire Tumbler ExtinguisherA fire in the home is always to be feared. And a fire in your reloading room can be disastrous. Near your reloading bench you probably have flammable solvents, and maybe gunpowder. What would happen if an electrical fire started in your reloading room? Would you be alerted? Do you have a proper fire extinguisher at hand?

Here’s a true story from Forum Member Joe O. (aka “Joecob”) that provides a valuable safety lesson. After Joe started up his old tumbler, an internal connector worked loose, causing an arc which started a fire in his basement reloading area. Luckily Joe had a functioning smoke detector, and a fire extinguisher.

Very few of us would worry about fire when we plug in a tumbler or other AC-powered reloading tool. But there is always the possibility of a malfunction and a fire. Quick thinking (and a handy extinguisher) prevented serious damage to Joe’s reloading room and house — but things could have been worse (much worse), had Joe not responded quickly.

Fire in the Reloading RoomReport by Joecob
The day before ‘Sandy’ hit I was cleaning brass the way I always have. I set the vibratory tumbler on the back of my reloading bench in the basement. I loaded the media hopper with 40 fired empty brass cases (and walnut media), plugged the cord in, turned the tumbler on and went back upstairs to watch TV. I could hear the tumbler running in the background.

About half an hour later I heard the basement smoke alarm go off. I ran downstairs. Flames were licking from the melting plastic of the tumbler.

ABC fire extinguisherI grabbed the nearby ABC cannister extinguisher and squirted out the fire and soaked the charred bench areas with water. Good thing I had the extinguisher! And I was glad I religiously store powder and primers properly — away from the bench (and everything else).

What caused the fire? It looks like an internal AC connector finally vibrated loose enough to arc and ignite the plastic. WHEH! I had been using that thing for 25 years the same way without mishap. Guess I should have known to periodically check the guts of a thing that plugs in and vibrates for a living?

Today I went out and bought a new even bigger ‘Pro’ ABC extinguisher, plus a dual-detector smoke alarm, and an ultrasonic cleaner. That experience was scarier than the storm. I hope this true account might help someone else to avoid a bad experience.

In his account, Joe refers to an “ABC” cannister fire extinguisher. The “ABC” refers to the fire classification rating: Class A (trash, wood, and paper), Class B (liquids and gases), and Class C (energized electrical equipment) fires. There are many brands of ABC-rated extinguishers.

The rechargeable Kidde 210 unit contains four pounds of a multipurpose monoammonium phosphate dry chemical extinguishing agent. It has a discharge time of 13 to 15 seconds, a discharge range of 10 to 15 feet, and an operating pressure of 100 PSI. The seamless aluminum cylinder measures 4.5 inches in diameter and 15.7 inches tall. The Kidde 210 has a six-year limited warranty.

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December 28th, 2014

Tips for Loading Straighter Ammo with Less Run-Out

This article originally appeared in Sinclair Intl’s Reloading Press Blog, which has been merged into the Gun Tech Section on Sinclair’s website, www.SinclairIntl.com

Steps to Minimize Bullet Run-Out

Poor bullet run-out can cause poor and inconsistent accuracy, and variations in bullet velocities. The truer the loaded round, the more consistent your results will be on paper and across the chronograph.

Sinclair Concentricity gaugeMeasuring Concentricity
We all know that low run-out is the goal. But how can you tell if your run-out is high or low? Run-out is generally measured in thousandths of an inch with a concentricity gauge. There are many concentricity gauges to choose from that work well. Some work on loaded rounds only, some have a bullet straightening feature, and a few work on both loaded rounds and empty cases for checking case neck concentricity. The tool of choice for the Sinclair Reloading Tech Staff is the Sinclair Concentricity Gauge (Part # 09-175).

This tool is a mainstay on my bench, and it is used about as much as I use my reloading press! The tool uses two sets of bearings that are set on lateral, length-adjustable anodized aluminum blocks to accommodate cartridges from .221 Fireball-sized cases up to .50 BMG. The indicator is set on a height adjustable swiveling base on a stand that can be used for checking bullet or case neck run-out. The adjustable blocks ride aligned in a precision-milled slot. The entire set up is on an anodized base plate that gives excellent support during the process that is crucial to operation and accuracy. Basically the operation consists of placing a loaded round (for checking bullet run-out) or an empty case (for case run-out) on the bearings with the indicator end touching the chosen point to be measured. The case is easily spun with one finger as the indicator measures the amount of run-out. Once this process has been done a few times it is a fast and accurate means of measurement. In terms of indicator type being used, whether dial or digital, I actually prefer a standard dial indicator over the digital type. My reason for this choice is that you can see the needle jump when run-out is present. I believe this to be easier and faster than looking at digital numbers while measuring. In the video below, Sinclair’s Bill Gravatt shows how to use the Sinclair Concentricity Gauge correctly.

YouTube Preview Image

Sizing Steps to Minimize Run-Out
One of the most common steps in the reloading process that contributes to bullet run-out occurs is the sizing operation. If improper techniques are used or there are issues with the sizing die set up, a once perfectly concentric case can become out of whack. By using the proper dies for your application, properly setting up the die/shell holder or floating the de-capping/expander assembly, you can eliminate problems before they happen.

Sinclair Concentricity gaugeMany of us on the technical staff choose the Redding Type-S series of dies. These are full-Length or neck sizing dies that utilize a removable/changeable neck bushing (sold separately) to size the neck according to your application. These dies are machined with true precision and quality in mind. The Type-S dies come with a standard de-capping assembly with a caliber-specific expander ball in place. In addition to this an undersized retainer to hold the de-capping pin is included with the die. In my experience with these dies I use the standard expander ball with new, unfired brass on the initial re-size. I will then use the undersized retainer in place of the expander ball with brass that has been fired. I have found this step crucial in my reloading regiment to minimize bullet run out. The use of the expander ball can cause a few thousandths of run-out when the case is being pulled back out of the sizing die. With the undersized retainer in place the only thing that touches the neck of the case in sizing is the bushing. If you prefer to use an expander ball, Redding offers caliber specific carbide floating expander balls that fit on the de-capping rod. This free floating expander ball will self center on the case neck, and reduce the amount of run-out that can be caused by a standard expander ball.

When setting up a Type-S sizing die, set the neck bushing into the die with the numbers facing down toward the body of the die. Tighten the de-capping assembly until it contacts the bushing and then back it off ¼ of a turn. This allows the bushing to free float in the die. You should be able to hear the bushing rattle if you shake the die. Having the bushing free floating self centers the neck, and again minimizes any run-out that can occur.

If you prefer other brands of sizing dies there are a few tricks that people use to minimize run-out as well. Many reloaders claim that the use of an O-ring at the base of the de-capping assembly lock nut will float the assembly and help self center during sizing. Another trick that has been used is to remove the retaining pin on the shell holder slot on the press ram, and use an O-ring in its place to hold the shell holder in place. This allows the shell holder to self center during sizing as well.

Seating Steps to Minimize Run-Out
Run-out issues can arise during the bullet seating process. To reduce run-out during seating, use a high-quality die with a sliding sleeve. The sliding sleeve perfectly aligns the case with the bullet to be seated. Good examples of these dies are the Redding Competition Micrometer bullet seating dies, Forster Ultra Seaters, or RCBS Competition Seating dies. All of these dies utilize a micrometer top to precisely set seating depth. They are all very high quality dies that have tight tolerances to maximize bullet straightness during seating.

We receive many questions about seating long pointed bullets such as the Berger VLD or Hornady A-Max. One problem that the reloader faces with longer bullets is that they are so long that the standard seating stem is not machined deep enough to contact these bullets properly. The point of the bullet “bottoms out” in the stem and the result is off-center seating and/or rings and dents on the bullet nose. If you plan on using such bullets, you should purchase a “VLD” style seating stem, which is cut to accommodate the longer bullets. The use of this stem results in truer seating of the bullet without leaving a ring or marring the tip of the bullet.

Besides using a traditional press and threaded seating die, another great way to get a true bullet seat is by using an arbor press and Wilson chamber-type seating die. These dies are cut to very tight tolerances and have proven themselves as the main choice for bench rest enthusiasts. The design of the die positively aligns the case with the bullet as they are both captured by the die before the bullet is pushed straight into the case by the stem. These seating dies are available with the standard seating cap and stem or an additional micrometer top can be added for precise adjustment. Wilson also offers a stainless seating die with an integral micrometer seating head.

Finally another trick used by many in the seating process is to turn the case while the bullet is being seated. Some people claim this will keep things straight. What they do is raise the ram in increments while seating and rotate the case in the shellholder in increments of 90 degrees from the original starting while the bullet is being seated. Personally I have tried this and have seen no significant difference at all. However you may be the judge of this one. It makes sense, and maybe I should try this a little more before I rule it out.

After the Rounds Are Loaded — Batch Sorting by Concentricity Levels
No matter how meticulous you are, and no matter how good your components and tools are, run-out will still show up. Reloaders can drive themselves crazy trying to make each and every loaded round a true “0” in run-out. You will still see some minimal amount no matter what you do. Set yourself a standard of maximum allowable run-out for your loads. For instance for my Long Range 600- and 1000-yard F-Class loads I like to see .002” or less. I average .0015” and see a few in the range up to .004”. I spin each loaded round on my Sinclair Concentricity Gauge and sort them by run-out. Those that run over .002” I use for sighters or practice. Though achieving zero run-out (on every round) isn’t possible, minimizing run-out can definitely help your performance. Not only will your loads shoot better but you will have one less thing to worry about when you are lining up the sights on the target.

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December 27th, 2014

TECH TIP: Use a Block to Maintain Front Bag Shape

front rest bag blockHere’s a simple solution for lumpy front sandbags. Cut a small block the width of your fore-end and place that in the front bag between matches. You can tap it down firmly with a rubber mallet. This will keep the front bag nice and square, without bunching up in the center. That will help your rifle track straight and true. Rick Beginski uses wood (see photo), while our friend John Southwick uses a small block of metal. The metal block might work a little better, but the wood version is easier to make with simple tools. John Loh of JJ Industries offers a slick Delrin block with a built-in bubble level. Loh’s block helps ensure that the actual top surface of your front bag is level, as distinct from the front rest assembly.

John Loh Front Rest JJ Industries

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