Hot-Rodding the RCBS ChargeMaster Powder Dispenser

The RCBS ChargeMaster 1500 electronic powder scale and dispenser is the most popular product of its kind on the market. In our original Electronic Powder Dispenser Comparison Test, the ChargeMaster normally dispensed most kinds of powder faster than competitive units from Lyman and PACT. However, after the initial release of the ChargeMaster 1500, RCBS “tweaked” the software a bit to achieve more consistent charge-throws. This slowed down the process somewhat. Some owners have wanted to speed up their ChargeMaster. This IS possible with a relatively simple reprogramming. Most of the internal parameters of the Chargemaster can be modified, under guidance from the tech staff at RCBS.

Gunsmith and Forum member NAT Lambeth reports: “I thought My RCBS ChargeMaster 1500 Combo was fast enough. But I still called RCBS and asked for the programing changes to see if I could speed it up. It was a lot easier than I thought. My 1500 Combo was taking from 15-30 seconds to dispense the powder to the tenth of a grain. I reprogrammed the numbers and now it takes between 7 and 15 seconds to dispense to a tenth. This effectively doubled my loading speed. I only changed the HSB_A1, HSB_B1, and BSP_C1 settings.”

Key ChargeMaster Parameters with Default Settings
HSB_A1 (15.68) Grains under target weight to go from full to high speed
HSB_B1 (3.42) Grains under target weight to go from high to slow speed
BSP_C1 (1.08) Grains under target weight to go from slow to final trickle speed

Nat cautions that you should talk to a RCBS tech before attempting to re-program your ChargeMaster: “You will benefit from talking to the RCBS tech. I have now gone back and played with the numbers a couple of times. (The numbers given to me by the tech at RCBS were still a little conservative.) I think each machine may have its own likes and dislikes. If you get too aggresive with lowering your numbers it will over-throw your intended load.“

Source for ALL the Parameters
There is an extensive discussion of RCBS ChargeMaster programming on the South Africa Hunting Rifle Shooting Assn. (SAJSV) Forum. In this SAJSV Forum ARTICLE, Jaco Brink lists virtually all the programming codes. Importantly, Jaco also provides the default values for various parameters. This is very important, because the ChargeMaster does not have a “return to default” option. Once you change any value, if you want to return to the original value you must enter it manually. Jaco cautions: “I have to advise you to only make changes to your scale if you are confident to do so, and remember that there is not a ‘return to default’ setting in the scale. If all else fails return your scale to the default settings [I have listed].”

CLICK HERE for list of RCBS ChargeMaster Default Programming Values

Use a McDonald’s Straw to Reduce “Over-Throws”
Jaco Brink provided another useful tip to avoid “over-throws” (excess charge weight): “The RCBS employee advised me to take a McDonnell’s straw (because it is thicker than a normal straw), cut off about a half inch piece and put it into the tube where the powder exits. This caused the last [few kernels] of an extruded powder to cluster less, and reduced the amount of overthrows dramatically.”

CLICK HERE for more ChargeMaster 1500 optimization TIPS.

Spotting Scope Resolution at 1000 Yards (in Ideal Conditions)

While attending the CA Long Range Championship recently, we had the opportunity to test the performance of a high-magnification (63X) spotting scope in near-ideal conditions (maybe the best I’ve ever witnessed). On the event’s last day we arrived at 5:45 am, literally as the sun was cresting the horizon. I quickly deployed our Pentax PF-100ED spotting scope, fitted with a Pentax SMC-XW 10mm fixed-power eyepiece. When used with the 100mm Pentax scope, this 10mm eyepiece yields 63X magnification. Befitting its $359.00 price, this eyepiece is extremely clear and sharp.

At the crack of dawn, viewing conditions were ideal. No mist, no mirage, no wind. The first thing this Editor noticed was that I could see nail heads on the target boards — that was pretty amazing. As soon as the first practice targets went up, to my surprise, I could see 6.5mm, 7mm, and 30-caliber bullet holes in the white at 1000 yards.

That’s right, I could see bullet holes at 1000. I know many of you folks may not believe that, but there was no mistaking when I saw a 7mm bullet cut the white line separating the Nine Ring and Eight Ring on the target in view. (I was watching that target as the shot was fired and saw the shot-hole form). And when I looked at the 30-cal targets, the bullet holes in the white were quite visible. In these perfect conditions I could also make out 3/8″ bolt heads on the wood target frames.

The Human Factor
When viewing the bullet holes, I was using my left naked eye (no safety glasses or magnification). I also had a contact lens in my right eye (needed for distance vision). To my surprise, while I could see the bullet holes without much difficulty with my left eye, things were fuzzier and slightly more blurry with the right eye, even when I re-focused the scope.

Then I invited 3 or 4 shooters to look through the scope. One younger guy, with good eyes, said immediately: “Yeah, I can see the holes — right there at 4 o’clock and seven o’clock. Wow.” Some older guys, who were wearing glasses, could not see the holes at all, no matter what we did to the scope’s main focus and diopter adjustment.

The lesson here — if you have to wear glasses or corrective contact lenses, just that extra bit of optical interference may make a difference in what you can see through the scope. Basically anything that goes between the scope eyepiece and your eyeball can degrade the image somewhat. So… you may be better off removing your glasses if you can still obtain good focus sharpness using the diopter adjustment and focus ring. I did the left vs. right eye test a half dozen times, and I could definitely see small features at 1000 yards with my naked eye that I could not see with my right eye fitted with a contact lens. (I did have to re-focus the scope for each eye, since one had a corrective lens while the other did not.)

Mirage Degrades Image Sharpness and Resolution
The “magic light” prevailed for only an hour or so, and then we started to get some mirage. As soon as the mirage appeared I was no longer able to see raw bullet holes, though I could still easily see black pasters on the black bulls. When the mirage started, the sharpness of the visible image degraded a huge amount. Where I could see bullet holes at dawn, by mid-morning I could barely read the numbers on the scoring rings. Lesson: If you want to test the ulimate resolution of your optics, you need perfect conditions.

Chromatic Aberration Revealed
As the light got brighter and the mirage increased I started to see blue and red fringing at the edges of the spotting disk and the large numerals. This was quite noticeable. On one side of the bright, white spotting disc you could see a dark red edge, while on the other side there was a blue edge (harder to see but still present).

The photo below was taken through the Pentax spotter lens using a point and shoot camera held up to the eyepiece. The sharpness of the Pentax was actually much better than this photo shows, but the through-the-lens image does clearly reveal the red and blue fringing. This fringing is caused by chromatic aberration — the failure of a lens to focus all colors to the same point. Chromatic aberration, most visible at high magnification, causes different wavelengths of light to have differing focal lengths (see diagram). Chromatic aberration manifests itself as “fringes” of color along boundaries that separate dark and bright parts of the image, because each color in the optical spectrum cannot be focused at a single common point on the optical axis. Keep in mind that the Pentax does have “ED” or low-dispersion glass, so the effect would be even more dramatic with a cheaper spotting scope.

CLICK HERE to view LARGE PHOTO that shows aberration more clearly.

If you have wondered why the latest top-of-the-line spotting scopes (such as the $3995 Leica APO-Televid 82) cost so much, the answer is that they will deliver even LESS chromatic aberration at long range and high magnification. With their exotic apochromatic (APO), ultra-low-dispersion glass, a few ultra-high-end spotting scopes can deliver an image without the color edging you see in the photo above.

The Pentax PF-100ED is a heck of a spotting scope. Any scope that can resolve bullet holes at 1000 yards is impressive. The body on this unit now runs about $1700.00 by itself, or you can get the PF-100ED with a 26-78X zoom lens for about $1900.00. But if you want the ultimate in optical performance, with minimal chromatic aberration, you may need to step up to something like the 88mm Kowa Prominar TSN-883 with Flourite Crystal lenses ($2310.00 body only), or the 82mm Leica APO ($3995.00 with 25-50X eyepiece). Plus, we’ve heard reports that Zeiss is working on a new APO “Über-scope” for release next year.

EDITOR’s NOTE: The purpose of this report is to show what is possible… in IDEAL conditions. With this Pentax 100mm, as well as a Swarovski 80mm, we have often been able to resolve 6mm bullet holes at 600 yards. But again, that performance requires really good viewing conditions. By 10:00 am at my range, even with the 100mm Pentax at 75 power, seeing 6mm bullet holes is “iffy” at best. So don’t go out and mortgage the house to buy a $4000 optic with the hope that you’ll be able to spot your shots at 1000 yards. If conditions are anything less than perfect, you’ll be lucky to see bullet holes at 500 yards. The real solution for very long-range spotting is to set up a remote target cam that broadcasts a video picture to a screen at your shooting station.

Primers and Load Velocity: CCI-BR2 vs. Wolf in .308 Win

We are often asked “Can I get more velocity by switching primer types?” The answer is “maybe”. The important thing to know is that changing primer types can alter your load’s performance in many ways — velocity average, velocity variance (ES/SD), accuracy, and pressure. Because there are so many variables involved you can’t really predict whether one primer type is going to be better or worse than another. This will depend on your cartridge, your powder, your barrel, and even the mechanics of your firing pin system.

Interestingly, however, a shooter on another forum recently did a test with his .308 Win semi-auto. Using Hodgdon Varget powder and Sierra 155gr Palma MatchKing (item 2156) bullets, he found that Wolf Large Rifle primers gave slightly higher velocities than did CCI-BR2s. Interestingly, the amount of extra speed (provided by the Wolfs) increased as charge weight went up, though the middle value had the largest speed variance. The shooter observed: “The Wolf primers seemed to be obviously hotter and they had about the same or possibly better ES average.” See table:

Varget .308 load	45.5 grains	46.0 grains	46.5 grains
CCI BR2 Primers	2751 fps	2761 fps	2783 fps
Wolf LR Primers	2757 fps	2780 fps	2798 fps
Speed Delta	6 fps	19 fps	15 fps

You can’t extrapolate too much from the table above. This describes just one gun, one powder, and one bullet. Your Mileage May Vary (YMMV) as they say. However, this illustration does show that by substituting one component you may see significant changes. Provided it can be repeated in multiple chrono runs, an increase of 19 fps (with the 46.0 grain powder load) is meaningful. An extra 20 fps or so may yield a more optimal accuracy node or “sweet spot” that produces better groups. (Though faster is certainly NOT always better for accuracy — you have to test to find out.)

WARNING: When switching primers, you should exercise caution. More speed may be attractive, but you have to consider that the “speedier” primer choice may also produce more pressure. Therefore, you must carefully monitor pressure signs whenever changing ANY component in a load.

Plenty of CCI-BR2 and Wolf Large Rifle Primers in Stock
If you’re looking for either the CCI BR-2 or Wolf Large Rifle Primers, Wideners.com currently has both in stock. The CCI BR2 primers (item CCIBR2) cost $42.50 per 1000. The Wolf LR Primers (item QQQLR KVB-7) cost $29.50 per 1000 OR $142.00 per 5000.

Barrel “Depreciation” and the True Cost of Shooting

How much does it cost you to send a round downrange? Ask most shooters this question and they’ll start adding up the cost of components: bullets, powder, and primers. Then they’ll figure in the cost of brass, divided by the number of times the cases are reloaded.

For a 6BR shooting match bullets, match-grade primers, and 30 grains of powder, in brass reloaded a dozen times, this basic calculation gives us a cost per shot of $0.46 (forty-six cents):

Bullet $0.30 (Berger 105 VLD) MidwayUSA
Primer $0.03 (Wolf SmR magnum) Wideners
Powder $0.08 (Reloder 15 @ $18.85/lb) Powder Valley
Brass $0.05 (Lapua priced at $63/100, 12 reloads) Brunos

Total $0.46 per round

$1.00 Per Shot True Cost? Yikes!
OK, we’ve seen that it costs about $0.46 per round to shoot a 6BR. Right?

Wrong! — What if we told you that your ACTUAL cost per round might be closer to double that number? How can that be? Well… you haven’t accounted for the cost of your barrel. Every round you fire down that tube expends some of the barrel’s finite life. If, like some short-range PPC shooters, you replace barrels every 700 or 800 rounds, you need to add $0.60 to $0.70 per round for “barrel cost.” That can effectively double your cost per round, taking it well past the dollar per shot mark.

Calculating Barrel Cost Per Shot
In the table below, we calculate your barrel cost per shot, based on various expected barrel lifespans.

As noted above, a PPC barrel is typically replaced at 700-800 rounds. A 6.5-284 barrel can last 1200+ rounds, but it might need replacement after 1000 rounds or less. A 6BR barrel should give 2200-3000 rounds of accurate life, and a .308 Win barrel could remain competitive for 4,000 rounds or more.

The table below shows your barrel cost per shot, based on various “useful lives.” We assume that a barrel costs $500.00 total to replace. This includes $300.00 for the barrel itself, $160.00 for chambering/fitting, and $40.00 in 2-way shipping costs. Yes, you may have a smith that works for less, but these are typical costs shooters will encounter when ordering a rebarreling job.

The numbers are interesting. If you get 2000 rounds on your barrel instead of 1000, you save $0.25 per shot. However, extending barrel life from 2000 to 3000 rounds only saves you $0.08 per round.

NOTE: We assume component costs of $0.46 per round based on our 6BR example. If you shoot a larger caliber that burns more powder, and uses more expensive bullets and/or brass, your total cost per round will be higher.

How to Reduce Your TRUE Cost per Round
What does this tell us? First, in figuring your annual shooting budget, you need to consider the true cost per round, including barrel cost. Second, if you want to keep your true costs under control, you need to look at ways to extend your barrel life. This can be accomplished in many ways. First, you may find that switching to a different powder reduces throat erosion. Second, if you’re able to slow down your shooting pace, this can reduce barrel heat, which can extend barrel life. (A varminter in the field is well-advised to switch rifles, or switch barrels, when the barrel gets very hot from extended shot strings.) Third, modifying your cleaning methods can also extend the life of your barrel. Use solvents that reduce the need for aggressive brushing, and try to minimize the use of abrasives. Also, always use a properly fitting bore guide. Many barrels have been prematurely worn out from improper cleaning techniques.

Greatest Hits: Ballistics App for I-Pods and I-Phones

LINK: Advanced Ballistics Program for I-Phones and I-Pods
Apple’s I-Phone and I-Pod offer a superb user interface with serious computing power. Here’s a very trick software App (good enough for the U.S. military) that runs ballistic calcs and even has a bullet database.

Tech Tip: Same Load Varies in Velocity with Different Barrels

Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.

Chron Testing Lapua Factory Ammo
We recently chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.

Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels. Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest.

Results Are Barrel-Specific, Not Brand-Specific
These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.

Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.

Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6BR, .243 Win, 6.5×47 Lapua, 6.5×55, .308 Win, 30-06, or 300 WM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. When you complete a new 6BR rifle, it’s wise to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.

Combat Corrosion with Rust-Fighting Products

Winter is coming and that means cold temps and wet weather. Heck it’s even raining in California this week. When it’s cold and damp out, you need to pro-actively guard against rust and corrosion on your valuable tools and firearms. As temperatures drop, moisture can condense from the air, causing guns to rust, even if they are stored in a safe.

We recommend that you use a proven corrosion inhibitor to protect your firearms during winter storage. We did extensive testing and recommend three products to combat rust: BoeShield T-9, Corrosion-X, and Eezox. These are all excellent products, but this Editor’s first choice is Eezox, because it cleans as well as protects, and because Eezox does not leave a sticky or waxy coating on your arms. Eezox is also ideal for fine, blued firearms. After 2-3 light applications it provides a dry protective finish that allows high polish blueing to shine through.

CLICK HERE for Anti-Corrosion Product Test Results

Eezox is available in small drip bottles, 4-oz. cans, and 4-, 6-, and 18-oz. aerosol spray cans. We typically apply Eezox to a patch from an aerosol can, then wipe down the firearm. Let the Eezox dry, then reapply. This will give you outstanding protection. Just make sure you wipe down ALL the metal surfaces, which may require removing the barreled action from the stock. We’ve seen examples of guns that rusted on the underside of the action because the owner had only bothered to wipe down the barrel and exposed section of the action. You can purchase Eezox from gun stores, MidwayUSA ($8.99 for 7 oz. can), or Warren Custom Outdoor.

Foam Cases Are Rust Magnets — Use Bore Stores
Just about the worst thing you can do in the winter (short of leaving your rifle outside in the rain) is to store firearms in tight, foam-padded cases. The foam in these cases actually collects and retains moisture from the air, acting as the perfect breeding ground for rust.

Those plastic-shelled cases with foam interiors are for transport, not for long-term storage. Don’t repeat the mistake of a wealthy gun collector I know. He stored four valuable Colt Single Action Army (SAA) revolvers in individual foam-padded cases, and locked these away in his gun safe. A year later, every one of his precious SAAs had rusted, some badly.

For storing long guns in your safe, we strongly recommend Bore Stores. These synthetic fleece gun sacks are coated with silicone and corrosion inhibitors. The thick fleece also protects your guns from nicks and scratches. Rifle-size Bore Stores can be purchased for $12.00 – $16.00 from Brownell’s or MidwayUSA, or direct from the manufacturer Big Spring Enterprises, which can also craft custom sizes on request.

Gauge Low-Light Scope Performance with ScopeCalc.com

Hunters and tactical shooters need scopes with good low-light performance. For a scope to perform well at dawn and dusk, it needs good light transmission, plus a reasonably large exit pupil to make maximum use of your eye’s light processing abilty.* And generally speaking, the bigger the front objective, the better the low-light performance, other factors being equal. Given these basic principles, how can we quickly evaluate the low-light performance of different makes and models of scopes?

Here’s the answer: ScopeCalc.com offers a FREE web-based Low-Light Performance Calculator that lets you compare the light gain, perceived brightness, and overall low-light performance of various optics. Using this scope comparison tool is pretty easy — just input the magnification, objective diameter, exit pupil size, and light transmission ratio. If the scope’s manufacturer doesn’t publish an exit pupil size, then divide the objective diameter in millimeters by the magnification level. For example a 20-power scope with a 40mm objective should have a 2mm exit pupil. For most premium scopes, light transmission rates are typically 90% or better (averaged across the visible spectrum). However, not many manufacturers publish this data, so you may have to dig a little.

ScopeCalc.com’s calculator can be used for a single scope, a pair of scopes, or multiple scopes. Once you’ve typed in the needed data, click “Calculate” and the program will produce comparison charts showing Light Gain, Perceived Brightness, and Low-Light Performance. In the example below, we compared a “generic” 5-18×50 Tactical scope with a “generic” 8-32 Benchrest scope.

Though the program is easy to use, and quickly generates comparative data, assessing scope brightness, as perceived by the human eye, is not a simple matter. You’ll want to read the annotations that appear below the generated charts. For example, ScopeCalc’s creators explain that: “Perceived brightness is calculated as the cube root of the light gain, which is the basis for modern computer color space brightness scaling.” In addition, the way ScopeCalc measures Low-Light Performance is pretty sophisticated: “Low Light Performance [is calculated] as the average of light gain and resolution gain through magnification, as a measure of target image acuity gain in low light similar to Twilight Performance specified by scope manufacturers. Low Light Performance calculated here is much more useful than Twilight Performance, as Twilight performance is the average of the just the objective lens diameter times magnification, while Low Light Performance is the average of the actual Perceived Brightness times magnification, which also includes the exit pupil/eye pupil relation, light transmission, approximated diffraction, as well as the perception of relative light gain. Just as with Twilight Performance, this Low Light Performance calculation does not yet include lens resolution and contrast as factors. Therefore lower quality optics will yield relatively less gains at higher magnifications.” Got that?

*In low light, the human eye can typically dilate to 5mm – 7mm. The exact amount of dilation varies with the individual, and typically declines, with increasing age, from 7mm (at age 20) to a dark-adapted pupil of about 5.5mm by age 65. To take full advantage of a scope’s light-gathering capacity, the diameter of an eyepiece exit pupil should be no larger than the max diameter of your eye’s dark-adapted pupil, so that all of the light collected by the scope enters your eye, rather than falling on the iris. A large 8mm exit pupil may seem good, but it would be partly “wasted” on a shooter in his 60s.

Don’t Over-Chamfer Your Necks — Bullet Damage Can Result

Shaving bullet jackets is a problem reloaders encounter from time to time. It can be caused by excessive neck tension, burrs on the case mouth, or over-aggressive chamfering that leaves a ragged edge on the case mouth. Larry Medler discovered some rounds where the bullet jackets were getting shaved. Diagnosing the problem, he found that this was caused by his outside neck chamfer. He was using a powered screwdriver to rotate the case, and over-cutting plus tool chatter was causing the case neck to roll inwards. This created a thin, sharp edge that actually cut into the bullet jacket as the bullet was being seated.

Larry has a Load Force 250 measuring instrument that records the dynamic bullet seating force and displays the results on a computer screen. Larry noted that spikes in seating force were associated with the cases where the bullets were shaved. Inspecting the cases, Larry realized what was happening. Chamfering the outside after doing the inside allowed his tools to cut too much. Combined with tool chatter, this actually created a sharp, ragged edge that rolled inward towards the bullet: “I discovered I had rolled the case mouth rim inward while deburring the outer edge. When deburring the case mouth on the outside edge, every now and then I could hear some tool chatter. The effects of this chatter really show in the picture.”

The above chart shows the dynamic bullet seating force for the bullet with the shaved jacket. Note the large initial force used to cut and scratch the bullet outer surfaces. The final seating force of 47 pounds is just before the Wilson Seating Die bottoms out and the force on the load cell jumps. The chart below shows normal bullet seating force.

As a fix, Larry decided to reverse the neck deburring operations. Now he deburrs the outside first. This reduces tool chatter and prevents the edge from rolling over, because the neck thickness has not been thinned by inside chamfering. While Larry uses a powered screwdriver to speed his case processing, the lesson applies to those who chamfer manually as well–do the outside first and never overcut.

Remember, you simply want to remove burrs and create a slight chamfer. You don’t want to thin the brass significantly at the case mouth. This is why it is important to be very careful when using a deep-angle cutter such as the K&M inside neck chamferer. Click HERE to read Larry’s full report on neck chamfering, with more details on use of the Load Force 250 measuring instrument. Using device such as this, or a K&M arbor press equipped with a seating force gauge, will help you diagnose problems with your neck tension and reloading procedures.

Shot Order and Calibration When Using Electronic Scales

Here’s a tip that can help you score higher at matches and get more predictable results when weighing loads with an electronic scale. Kelly Bachand, a top prone shooter and electrical engineering major at the Univ. of Washington, tells us that all digital scales can drift. Therefore Kelly recommends re-calibrating electronic scales often. In addition — and this is key — Kelly recommends that you shoot the ammo in the exact order in which it was loaded. Arrange your loaded ammo in a box in the order of loading and shoot it first-loaded to last-loaded. (Or, if you prefer, shoot it last-loaded to first-loaded.) The important thing is to maintain the order and not mix everything up. That way, if your scale drifts, the effect of drift on charge weight will be incremental from one loaded round to the next, so point of impact change should be negligible. Conversely, if you shoot your last-loaded round right after your first-loaded round, the effect of scale drift is at its maximum, so powder charge varience is maximized. And that can produce a different point of impact (POI) on the target.

Tips on Loading with Electronic Scales
by Kelly Bachand
If you use a digital scale to measure powder charges, recalibrate the scale often. I like to do this about every 25 rounds or so. Additionally, most electronic scales rely on eddy currents for their precision. Eddy currents are easily disrupted by static electricity so keep a cloth or ground strap nearby to remove any static currents should the scale start acting up; I usually just use a fabric softener sheet that has gone through the dryer once.

Shoot Ammo in Order of Loading
I shoot my rounds in the same order or reverse order as I load them. If the charge weight varies due to scale drift during use, the difference will be gradual if I shoot in the same order as production (or reverse order). I should be able to adjust for the slight varience in charge weight without having any wildly high or low shots (see the charts below for a graphical demonstration). I usually load my ammunition just 100 rounds at a time. Give yourself plenty of time and remember that you will make your best ammunition when you are fully awake and alert.

This graph demonstrates the effect a .01% (that’s 1/100th of 1 percent) difference in scale measurement would have over the course of 100 rounds assuming the desired load is somewhere between 46 and 47 grains. The final round made would have almost 1% less (or more) powder than the first, that’s almost an 0.5 grain difference from the first. If shot back to back, these rounds will invariably have different points of impact on the target.

This graph demonstrates the same .01% difference in scale measurement but this time with a recalibration every 25 rounds. By recalibrating the scale every 25 rounds the furthest a weighed charge ever gets from the original is less than 0.25%. Again if the charge being weighed is between 46 and 47 grains then the 26th round made would vary from the 1st by .12 grains. Even that small difference would likely show on target.

Either way it is important to note that if the bullets are shot in the same (or reverse) order as they are made, the biggest difference from bullet to bullet in this example is less than .01 grains.

Improved Ultrasonic Cleaning with Citranox

Forum Member Dave B., aka “Gunamonth”, is a chemist/physicist with decades of experience working with the ultrasound process. He has achieved great results cleaning cases via ultrasound. Dave tried a variety of solutions and he favors a mix of water and Citranox®. This achieved the best results, and did not require a separate neutralizing step if you rinse the cases thoroughly after. Citranox, mixed 1:75 or 1:100 with water (distilled H20 is best), is inexpensive to use. Phospate-free Citranox® contains a blend of organic acids, anionic and non-ionic surfactants and alkanolamines. For more information on using Citranox®, check out THIS FORUM THREAD.

Dave notes: “I had a lot of communication with the technical VP of Alconox about trying to clean fired cases with an ultrasonic unit. He sent me a copy of his ultrasonic cleaning manual and recommended a product called Citranox®. So far I’ve been very impressed. With once- or twice-fired brass they clean up very quickly. The worst cases I tried were 6 Dashers that had been fired ten times with Varget and never cleaned. The worst fouling was in the bottom of the case around the flash hole. They took longer and I used a more concentrated cleaning solution but they did come out clean. The price is reasonable. I paid $35 a gallon and for once- or twice-fired cases I dilute the cleaner 100 to 1. There is much less chemical reaction with the brass than there is with vinegar. No weird colors, just shiny bright. I even used it with hot water, which speeds up the cleaning process. No need to neutralize. Just rinse in running water and they’re squeaky clean. The cleaner is mostly detergents with a little citric acid. Even at a 1:75 ratio my $35 worth of cleaner will make 75 gallons of solution. It doesn’t seem to be reusable but 75 gallons is a whole lot of solution when I only use about two cups at a time.”

The price has gone up a bit since Dave acquired his Citranox, but Amazon.com sells Citranox for $40.00 per gallon, or you can buy a gallon of Citranox from LabSafety Supply for $46.40.

Handy Excel Formula Predicts Useful Barrel Life

How long will a barrel last before the accuracy “goes south”? There are so many variables involved (powder type, bore diameter, bullet coatings etc.) that it’s hard to predict. You might say “Well, my buddy has a .243 and he got 1500 rounds before the throat was shot out” — those kind of comparisons can be useful, but they’re not very scientific, and they won’t help much if you’ve got a gun in a new chambering (such as the 6.5×47) for which long-term test results are lacking.

Is there a more reliable way to predict barrel life — one that will work for a broad range of calibers? Well, Forum member MikeCr has developed an Excel spreadsheet that accounts for a number of variables, and gives a pretty good estimate of useful barrel life, whether you’re shooting a .223 Rem or a 338 Lapua Magnum. Mike’s program predicts barrel life using five variables: 1) Bullet Diameter; 2) Powder Charge weight; 3) Powder Heat Potential (KJ/kg); 4) Pressure (in psi); and 5) Bullet Coating (yes/no). Mike provides a table with Heat Potential ratings for most popular powder types. The user needs to know the pressure of his load. This can be estimated with QuickLOAD.

You can download the lastest version of Mike’s spreadsheet below. You’ll need Excel or an Excel viewer to open the file.

Click to Download Spreadsheet: Barrel Life Spreadsheet (Latest Version)

Shown below is Mike’s Spreadsheet, with variables for a 6BR shooting 105gr “naked” bullets with 30.3 grains of Hodgdon Varget powder. The formula predicts 2401 rounds of barrel life. That corresponds pretty well to what we’d expect for a 6BR — about 2500 rounds.

Mike observes: “There has been alot of discussion lately related to cartridge design and resulting barrel life. This is a really important factor to consider amongst a myriad of choices. Barrel life is controversial, and subjective. There are no clear-cut standards for comparison. But a few years ago, I put together a spreadsheet based on Bart Bobbit’s rule of thumb. It worked pretty good, only occasionally failing some tests when validated against posted barrel lives.

According to Ken Howell, I had to account for pressure. And Henry Child’s powder temperature testing provided another piece needed. So, I’ve tweaked it here and there to pass more tests. From 223rem to 300 UltraMagnum. Another element added, but turned off is shot interval. I would need way more tests to lock in on this. But everyone knows, the faster you shoot, the worse the barrel life.

Anyway, another factor hard to define is ‘accurate’ barrel life. This cannot be quantified without standards. Barrels are replaced when expectations are no longer met. I feel that a [barrel] passes peak potential in a finite period due to throat erosion. But that don’t mean it’s toast, if it still shoots well enough. It’s just as likely that many of us never see that peak potential anyway. It’s a slippery thing. Point-blank BR competitors will toss a barrel when it leaves the 1s. I could get another 4000 rounds from it, and be content with its performance, I’m sure.”

NOTE: Mike says: “This spreadsheet may show a lower barrel life than you prefer. But it pretty well spotlights cartridges to stay away from if you plan much time at the range or in dog town.”

Editor’s Comment: We want to stress that Mike’s spreadsheet is a helpful tool, but it is not a definitive “take-it-to-the-bank” indicator of barrel life. Mike cautions that predicting barrel life involves so many different factors (including how hot the barrel is run), that the task is a bit like predicting tread life on car tires. Still, the spreadsheet is very helpful. It can certainly put shooters on notice that some chamberings (such as the 6-284) are likely to be a barrel burners. That can help you make a smart decision when choosing a chambering for your next rifle.