In this video, Forum member Erik Cortina shows how to create a custom modified case for use with the Hornady Lock-N-Load Overall Length Gauge (formerly the Stoney Point Tool). While Hornady sells modified cases for many standard cartridges, if you shoot a wildcat such as the 6mm Dasher or .284 Shehane, you’ll need to create a custom modified case*. And even if you shoot a standard cartridge such as the .308 Winchester you can get more consistent measurements if you make a custom modified case from a piece of brass fired in your chamber.
The process is straight-forward. Take a piece of brass fired in your chamber and full-length size it (with about .002″ shoulder bump). Then you need to drill out the primer pocket. Erik uses a mini-lathe for the operation, but this general process can be done with a drill press or other tools. Erik shows how to do this with a 0.290″ HSS (High Speed Steel) drill bit on a mini-lathe. After drilling the hole comes the tricky part — you need to tap the case with the precise 5/16″ x 36 threads per inch (tpi) right-hand thread that matches the male thread on the O.A.L. Gauge. This 5/16″ x 36 tpi tap is pretty uncommon, but you can order it from Amazon.com if you can’t source it locally.
If you use a mini-lathe, Erik suggests loosening the tailstock slightly, so it can float while cutting the threads. Erik also says: “Make sure you get the tap on pretty tight — it’s going to want to spin.” Erik turns the case at about 100 rpm when tapping the threads. Once the case and tap are rigged, the actual tapping process (see video at 6:00) takes only a few seconds. While the mini-lathe makes the tapping process go more quickly, the threading can also be done with other systems.
TIP: Don’t just make one modified case, make three. That gives you one for your range kit, one for your home reloading bench, plus a spare (since you WILL eventually lose or misplace one).
Here’s the Stuff You Need
5/16″-36 TPI Threading Tap
The required thread is somewhat uncommon. You need a 5/16″ – 36 tpi Right Hand Thread Tap. If you can’t find it locally, Amazon.com carries the correct tap. Erik notes: “The 5/16-36 tpi tap is not a common size. I think Hornady did this on purpose to make it more difficult for the average guy to make his own modified cases.”
0.290″ Drill Bit
Erik uses an 0.290″ HSS “L” drill bit. (This “L” Letter Gauge code designates a 0.290″ diameter bit). A close metric equivalent would be 7.3 mm (0.286″). Erik says: “A 9/32″ drill will also work but it will be harder to run the tap in since the hole will be .281″ instead of .290″ with the Letter Gauge L bit.”
Tips for Using O.A.L. Gauge with Modified Case
We’ve noticed that many folks have trouble getting reliable, consistent results when they first start using the Hornady O.A.L. Gauge (formerly the Stoney Point Tool). We’ve found this is usually because they don’t seat the modified case properly and because they don’t use a gentle, consistent method of advancing the bullet until it just kisses the lands.
Here is our suggested procedure for use the O.A.L. Gauge. Following this method we can typically make three of four measurements (with the same bullet), all within .001″ to .0015″. (Yes, we always measure multiple times.)
1. Clean your chamber so there is no build-up of carbon, debris, or lube. Pay particular attention to the shoulder area.
2. Screw the modified case on to the O.A.L. Gauge. Make sure it is seated firmly (and doesn’t spin loose). Note, you may have to re-tighten the modified case after insertion in the chamber.
3. Place your selected bullet so that the ogive (max bullet diameter) is behind the case mouth. This prevents the bullet from “snagging” as you insert the tool in the action.
4. Insert the O.A.L. Gauge into your chamber smoothly. Push a little until you feel resistance. IMPORTANT — You need to ensure that the shoulder of the modified case is seated firmly against the front of your chamber. You may have to wiggle and twist the tool slightly. If you do not have the modified case seated all the way in, you will NOT get a valid measurement.
5. Advance the bullet slowly. (NOTE: This is the most important aspect for consistency!). Push the rod of the O.A.L. tool gently towards the chamber. DON’T shove it hard! Easy does it. Stop when you feel resistance.
6. IMPORTANT. After gently pushing on the rod, give the end of the rod a couple forward taps with your finger. If your bullet was slightly skewed, it may have stopped too far back. Adding a couple extra taps will fix that. If the bullet moves after the taps, then again push gently on the rod. NOT too much! You just want to push the bullet until it just “kisses” the lands and then stops. Do NOT jam the bullet into the rifling. If you do that you will never get consistent results from one measurement to the next.
* For a $15.00 fee, Hornady will make a custom modified case for you if you send two fired pieces of brass. Send fired cases and $15.00 check to: Hornady Manufacturing, Attn: Modified Cases, 108 S. Apollo St., Alda, NE 68810. More Info HERE.
At the 2015 Berger Southwest Nationals, Forum member Erik Cortina cornered Bryan Litz of Applied Ballistics. Erik, the F-Open winner in the 600-yard Mid-Range match, was curious about bullet sorting. Knowing that bullets can be sorted by many different criteria (e.g. weight, overall length, base to ogive length, actual bearing surface length etc.) Erik asked Bryan to specify the most important dimension to consider when sorting. Bryan recommended sorting by “Base to Ogive”. Litz noted that: “Sorting by overall length can be misleading because of the nature of the open-tip match bullet. You might get a bullet that measures longer because it has a jagged [tip], but that bullet might not fly any different. But measuring base to ogive might indicate that the bullet is formed differently — basically it’s a higher resolution measurement….”
Ballistics Q & A in Shooter’s Forum
Got more questions about bullets? Our Shooters’ Forum has a special area for Bullets & Ballistics topics. There you can get your own questions about bullets and ballistics answered by Bryan Litz and other experts from Applied Ballistics.
This was supposed to be the “easy day” at the Berger Southwest Nationals (SWN), with targets at the “shorter” distance of 600 yards. But the wind gods did not cooperate. The wind blew all day long, with significant velocity changes (from strong to very strong) and tricky angle changes. It was a challenge even for a National Champion. James Crofts, reigning F-TR National Champ, said today presented the toughest wind conditions he’s ever witnessed at Ben Avery: “Conditions were brutal, to say the least. At 600 yards I found the 7 Ring, so it wasn’t easy”. But James was up to the task, winning the F-TR division. Forum member Erik Cortina took top F-Open honors in this Wednesday mid-range match. But he agreed with Crofts that the blustery winds were very challenging — with the high velocities you had to watch the right flags to pick out the angle changes.
In the video below, James and Erik talk about the challenge of shooting in these kind of conditions, and they also talk about their choices in F-Class hardware (rests, bipods, scopes).
After we posted Erik Cortina’s video featuring the trimming of 7mm Shehane cartridges with a Giraud Power Trimmer, many of our readers asked: “What’s a 7mm Shehane? How does it differ from a standard .284 Winchester?” To answer that question, we’re reprising a “cartridge profile” we ran a couple seasons back. This talks about the qualities of the 7mm Shehane, and includes a reamer print. The 7mm Shehane is an excellent “upgrade” to the .284 Win. The added capacity may not seem like much, but it allows some Shehane shooters to reach a higher, optimal velocity node.
7mm is the caliber to beat in F-Class Open Division (though many guys are looking hard at the big 30s.) With a standard .284 Winchester, or better yet, a .284 Improved, you can drive the high-BC Berger 180gr bullets to competitive velocities. A .284 Improved will shoot well inside a 6.5-284, and you’ll probably get significantly longer barrel life (at least 1800 rounds vs. as little as 1200 for the 6.5mm).
The straight .284 Win is a good cartridge, but in most barrels, it can’t push the 180s at 2900-2950 fps velocity levels*. A lot of barrels will top out at about 2850. That’s where the .284 Shehane comes into play. The .284 Shehane is a slightly modified wildcat that retains the same 35° shoulder as the parent case. However, by blowing the sidewalls out 0.010″, the .284 Shehane picks up about 3.3 grains of extra case capacity. That enhancement makes a BIG difference. The extra boiler room is enough to drive the 180s at 2900-2950 fps with H4831sc. With N560 or Reloder 17 you can go even faster.
Scotland’s Grant Taylor used the .284 Shehane to finish 3rd overall in the 2009 individual F-Class World Championships at Bisley, England. Grant reports: “I have a .284 Shehane and it’s very accurate with superb vertical spreads at 1000 yards. I have to thank Jim Hardy for putting me onto the caliber, it has awesome accuracy. I’m getting 2930-2950 fps with spreads in the 3-5 fps range. I use Hodgdon H4831sc powder, CCI BR2 primers, and pointed 180gr Bergers.”
Forum member Jim Hardy has shot the .284 with great success. He tells us: “In my humble opinion, the .284 Shehane is the best balanced long range round there is — bar none. I (perhaps_ have shot more of this chambering than anyone else, and it has proven better than I ever expected. Here is why:
You have to shoot a 30 Cal magnum with a 240gr bullet to equal the performance of most 7mm chamberings with the 180 Berger VLD. With the .284 Shehane, you have a .308 bolt face, medium action, and Lapua brass. You use less powder than the 7 mags, and have great accuracy and ballistics even while fire-forming. The .284 Shehane shoots inside the 6.5 AND the straight 284, the 300 WSM, and the 300 Win Mag with less recoil. The .284 Shehane offers twice the competitive barrel life of the 6.5-284, an easy 2950 fps with H4831 SC, [and it] can run 3000+ with N560 and Reloder 17, which is right there with the 7mm WSM. What is not to love about the 284 Shehane? It is a no-brainer for long range — F-Class or Prone or 1000-yard Benchrest.”
*Some exceptional barrels chambered in straight .284 Win can reach 2900 fps with the 180s. Ryan Pierce, who recently set a 450-24X Pending F-Open record, has a 32″ Brux barrel that is delivering 2900 fps with the straight .284. However, Ryan acknowledges that his velocities are not typical: “A lot of .284 Win barrels top out at around 2850 fps with the 180s.”
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.
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.)
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.
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.
7mm is the caliber to beat in F-Class Open Division (though many guys are looking hard at the big 30s.) With a standard .284 Winchester, or better yet, a .284 Improved, you can drive the high-BC Berger 180gr bullets to competitive velocities. A .284 Improved will shoot well inside a 6.5-284, and you’ll probably get significantly longer barrel life (at least 1800 rounds vs. as little as 1200 for the 6.5mm).
