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January 5th, 2013
Do you have an older Anschütz model 54-actioned match rifle with a press-in barrel? Perhaps you want to re-barrel your Anschütz to get a few more years of precision shooting out of the old warhorse? Or maybe you want to adapt the Anschütz to a modern stock design for Silhouette, Rimfire Benchrest, or Prone shooting. If you’ve got an older Anschütz m54 that needs re-barreling, you need to send it to a gunsmith who has a proven track record with the model 54s, a smith who can remove the original barrel properly and then install either a new press-in barrel, or a screw-in barrel (after threading the action).
 Mark Penrod — Recommended Anschütz Smith
Forum member Edward (aka EAL22) suggests sending Anschütz rimfire projects to Mark Penrod in North Manchester, Indiana. Writing in our Shooters’ Forum, Edward states:
“Penrod can fix you up. He can either press fit [a new barrel] or thread your action [for a screw-in barrel]. He has built guns both ways. Here are some photos of his work. It’s not a bench gun but a nice Anschütz in a System Gemini stock.”
Forum member Bill B. concurs: “I second the suggestion that you send it to Mark Penrod. I’ve just got done working with him on a Hall rimfire action to which he fitted two barrels, a Benchmark and a Lilja. I am building a prone position rifle. He was easy to work with providing good communication, and he’ll do whatever is needed to make your rifle shoot its best.”
Other Recommended Smiths — Bruce Hongista and MT Guns
Another recommended rimfire smith is Bruce Hongisto. Forum member Steve W., a benchrest shooter, says: “My suggestion is to email Butch Hongisto at Hongisto [at] fidnet.com. Butch does amazing work and has made two rimfires for Lapua to use in their factory accuracy evaluations in Finland. Write Butch and ask him which way you should go. He knows his stuff.”
In California, Chesebro Rifles (the successor to Mac Tilton’s MT Guns) has a vast selection of older Anschütz match rifles. Gunsmith Mark Chesebro can rebarrel an older model 54 as well as adapt older Anschütz rifles to modern stocks. Mark even is working on converting single-shot model 54s to repeaters fitted with sturdy, inexpensive CZ detachable magazines. I’ve held the prototype repeater conversion with a 24″ barrel, and it is very cool. I predict the rimfire tactical guys will be lining up to buy these single-shot-to-repeater conversions. Availability is still a few months away. For more info, visit ChesebroRifles.com.
January 3rd, 2013
 In our Shooters’ Forum a reader recently 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.
 Neck-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.
December 22nd, 2012
The NRA’s American Rifleman Online website has an excellent article showing how to construct a rock-solid Reloading Bench. There are plenty of photos, and a detailed set of Bench Blueprints showing all dimensions and listing all needed materials. This bench is very well designed, with many deluxe features, such as an upper drawer with fitted slots for die boxes, and large lower drawers with 100-lb rated slides to store heavy materials or tools. If you have good wood-working skills this would be an excellent project.
CLICK HERE to Download Article with Photos | CLICK HERE for Bench Blueprints
The author, Dave Campbell, offers good advice on building the bench top: “I ripped a sheet of 3/4″ AC plywood into two 24″ wide pieces and cut them to 72″ long. Then I glued them together to form a 72″ long, 1 1/24″ thick top. The trick here is to keep the edges smooth and flat so that the laminate will adhere properly and without voids. I chose a light grey laminate finish for the top because it’s easier to see what I am working on and keep clean. If you have never worked with laminate, remember it’s prudent to glue and rout the edges flush before gluing on the top. The top was attached to the carcass with eight steel L-shaped angle brackets and No. 10×1 1/4″ wood screws.”
Photos Copyright © 2008 The National Rifle Association, used by permission
December 17th, 2012
How to Set Up Your Full Length Sizing Die
by Ron Dague, Sinclair International Technician
From Sinclair’s Reloading Press Blog
At Sinclair International, we are often asked for a fool-proof method to set up a full-length sizing die, and begin reloading our fired cases. The method used by many target shooters today is to set up your full length die to closely match your rifle chamber and minimally full-length size your cases –as little as .001″ for bolt-action rifles. I prefer to use this method for all of my bolt-action cartridges.
STEP ONE
I like to de-prime five (5) cases (de-prime only, do not full length resize) and measure from the base of the case to the shoulder with our Sinclair Comparator Body (09-1000) and Bump Gage Insert(09-10200). We refer to this as our headspace measurement. Our Electronic Caliper (#MIC-14) works well and may be pre-set at .000” making this headspace measurement easy to capture. The Sinclair Comparator/Gauge Body and Bump Gage Inserts make this task fairly simple. L.E. Wilson Tools & Gages, Hornady Manufacturing, and RCBS all make similar units to achieve your headspace measurement.
 STEP TWO
With your full-length die threaded into your reloading press, loosen the lock ring and run the press ram up toward the full length die with a shell holder in place (with no case). Then, screw the die toward the shell holder until it stops. Back the die out of the press and away from the shell holder one full turn and set the lock ring finger tight.
STEP THREE
Lubricate each of the cases with your favorite sizing lube (my favorite is Imperial Sizing Die Wax) and resize a case. Again, take a headspace measurement from base to shoulder. [When running the case up into the die, be sure the press ram moves the full limit of its upward travel.] If there’s no change in the measurement from the fired dimension, loosen the die lock ring and turn the full length sizing die downward 1/8 of a turn. [Editor’s Note: You’ll need to use smaller turn amounts as you get close to the desired amount of bump. We suggest moving just a few degrees of die rotation at a time once you’ve reached the point where the die hits the shoulder without moving it back.] Now repeat the sizing process with a second lubricated case and take the measurement again. Keep rotating the die downward gradually (in small increments) and repeat the case sizing process until you see approx-imately .001”-.002” reduction to your fired headspace measurement. We prefer a headspace reduction of approximately .001″ – .002″ for bolt action rifles and .003″ – .005″ for semi-auto rifles. You can adjust to your rifle as to what works best. Don’t forget to load 10 rounds or so and try them from the rifle’s magazine to make sure they function properly.
Full-length Sizing vs. Neck-Sizing
Just a quick word on neck sizing…..I have personally never been a big fan of neck sizing. Often times when I put neck sized cases back in the rifle, the bolt would close with some drag, or it would be a bit “snug”. This was mostly recognized with factory rifles. I didn’t have any problems with accuracy, just with cycling the action for a follow up shot. If your rifle is custom chambered with the action straightened and trued, neck sizing will work well on 4-5 firing’s and then you will need to full length size or use a body die to set the shoulders back when the cases begin to “stick”. Hope these tips help make the use of a headspace gauge and full length die set up much easier.
Ron Dague
Sinclair Tech and Reloading Instructor
800-717-8211
rond@sinclairintl.com
Reloading Tip Courtesy Sinclair Int’l; Story Sourced by Edlongrange
December 13th, 2012
Most of us assume that if we weigh our powder carefully (down to the tenth of a grain or less) we can achieve a uniform powder fill from case to case in our handloads. Weighing does ensure that the weight of the propellant in each case is the same, but is the column of powder the same by volume each time? “Not necessarily” is the answer. An interesting experiment by our friend Boyd Allen demonstrates that the manner in which you place kernels in the case can make a significant difference in the height of the powder column within the brass case.
Using a Gempro 250 scale, Boyd measured exactly 30.6 grains of Vihtavuori N-133 powder. He then inserted this powder in the same cartridge case multiple times. (The case has a fired primer in place.) But here is the key — Boyd used various filling techniques. He did a slow fill, and a fast fill, and he also experimented with tapping and drop tubes. What Boyd discovered was that you can start with the exact same weight of powder (in fact the very same set of kernels), yet end up with vary different fill heights, depending on how you drop the kernels into the case. Look at the photos. Despite variations in lighting, the photos show the same 30.6 grains of powder, placed in the same cartridge, with four different methods.
Boyd Explains the Procedure Used for his Experiment.
EDITOR’s NOTE: So there is no misunderstanding, Boyd started with a weighed 30.6 grain charge. This identical charge was used for ALL four fills. After a fill the powder was dumped from the case into a pan which was then used for the next fill technique to be tried. So, the powder weight was constant. Indeed the exact same kernels (of constant weight and number) were used for each fill.
Boyd writes: “I used the same powder for all fills, 30.6 gr. on a GemPro 250 checked more than once. All fills employed the same RCBS green transparent plastic funnel. The fast drop with the funnel only overflowed when it was removed from the case neck, and 15 granules of powder fell on the white paper that the case was sitting on. The fast-funnel-only drop with tapping, was done with the funnel in place and the case and funnel in one hand, while tapping the case body with the index finger hard, many times (about 20 fast double taps). My idea here was to “max out” the potential of this tapping technique.
The slow drop with the funnel and 10″-long .22 cal. Harrell’s Precision drop tube, was done by holding the scale pan over the funnel and tapping the spout of the pan repeatedly on the inside of the funnel about 1/3 down from the top, with the scale pan tilted just enough so that the powder will just flow. Many taps were involved, again, to max out the technique.
Again, to be clear, after each case filling, the powder was poured from the case back into the scale pan carefully. You may notice the similarity between the fast drop with the drop tube, and the funnel only with tapping. Although I did not photograph it, fast tube drop and tapping (combined) improved on tapping alone, but only to about half as far down the neck as the slow with drop tube. Due to the endless possible permutations, I picked four and left it at that.
I believe that I can make the rough judgment that the scale pan funnel and drop tube technique, which involved a longer drop period, and probably less velocity at the top of the tube, left more room in the top of the case neck than the slow drop from the measure with the same drop tube. You have both pictures, so you can make the comparison.” — Boyd
Does Powder Column Height Variance Make a Difference?
Boyd’s experiment proves pretty conclusively that the method of dropping a given weight of powder can affect the height of the powder column in the case and the degree of powder compression (when a bullet is seated). He showed this to be true even when the exact same set of kernels (of constant weight) was used in repetitive loadings. This raises some interesting questions:
1. Will subsequent cartridge transport and handling cause the powder to settle so the variances in powder column height are diminished?
2. If significant inconsistencies in powder column height remain at time of firing, will the difference in fill level hurt accuracy, or result in a higher extreme spread in velocity?
3. Is there any advantage (beyond increased effective case capacity) for a tight (low level) fill vs. a loose (high level) fill?
We don’t know the answer to these follow up questions. This Editor guesses that, if we tested low-fill-height rounds vs. high-fill-height rounds (all with same true fill quantity by weight), we might see meaningful differences in average velocity. I would also guess that if you fired 10 rounds that exhibited quite a difference in powder column heights, you might see a higher ES/SD than if you shot 10 rounds loaded with a very consistent powder column height (either high or low). But further testing is needed to determine if these predictions are true.
December 9th, 2012
 Here’s a clever, easy modification for your RCBS ChargeMaster electronic powder dispenser. Many folks use a McDonald’s straw to smooth kernel flow out of the dispensing tube. Forum member Mike S. (aka in2deep) found that, even with a straw in place, he sometimes got clumps, which dropped 5-6 kernels at once, throwing off his dispensed weight.
Mike looked at the situation and ingeniously decided to trim the straw into little v-shaped arms or prongs. This helps to break up the clumps, so the kernels flow out the end of the tube more consistently during the dispense cycle. Mike writes:
Soda Straw Modification
This is a further tweak of the popular soda straw modification as the original mod would still allow Varget powder to collect in the straw and dump sometimes as many as 6 or 8 or even more extra kernels in the pan. It would sometimes signal an overcharge, but even when it didn’t there could be as many as 6+ kernels too high or too low (total spread of 12+).
The little arms (prongs) on the straw tend to separate the kernels into groups of 1 or 2 or 3 and prevents piling and many times the throw is now within 1 or 2 kernels of the desired weight.
Straw Cutting Tips — Mike found the shape/angle of the “arms” is very important. If the cuts are too fine or too course it allows the kernels to collect almost like before but the illustrated angle seems to allow an average of only 2 or 3 kernels per trickle input from the machine. This means that more charges are much closer to the actual desired weight and max kernel variances will be cut in less than half and there will be almost no overthrows.
Credit Boyd Allen for sourcing this tip.
December 9th, 2012
While many of us now favor digital photography over “old-fashioned” 35mm film, don’t toss those old 35mm film canisters, especially the clear Fuji-type with secure snap-in lids. Small plastic film canisters have a multitude of uses for the shooter and reloader.
Here Are Some of the Things You Can Do with Film Canisters:
1. If you weigh powder charges after throwing them with a manual powder dispenser, throw the charges first into a film canister and then use that to drop the powder into the measuring pan on your scale. The canister will catch every kernel of powder. If you throw charges directly into a weighing pan, powder can sometimes bounce out. Using the film canister will help keep spilled powder off your loading bench and floor.
2. Store extra sets of foam ear-plugs in the canister. You never want to be without ear protection. This editor has four film canisters filled with plugs. Two go in the range kit, one goes in the car’s glove compartment, and a second stays in a lock box I use to transport pistols. This way I never find myself at the range without ear protection.
3. Place your smaller cotton patches in film canisters, marked by caliber. If you use the water-tight Fuji-style canisters, you can even pre-soak the patches with solvent. You can have one canister for wet patches, another for dry patches. That saves time when you’re at the range, and avoids spillage. One caution–some solvents may react with plastic, so test this first before you put a solvent-filled canister in your range kit.
4. Use film canisters to hold your neck bushings, sorted by caliber. With a permanent marking pen, you can mark the side or top of the canister with the bushing sizes, or caliber.
5. Store your favorite Bolt Grease (for rifles) or anti-seize compound (good for pistol slide rails), in the canister. You don’t need to fill it all the way up — a little dab will do ya. We only recommend this with the snap-top Fuji canisters.
6. During transport, Protect your muzzle with canisters. When shipping a rifle or barrel, slip the film canister over the muzzle, then secure it with electrical tape. This will protect the precious crown of a match barrel from dings or damage.
There are countless other uses for 35mm film canisters. We invite readers to respond with their own tips on using these handy containers. If you don’t have some stashed in your workshop already, you can get empties for free at most film processing centers. The clear plastic Fuji canisters are the best — you can see what’s inside and the lids are watertight.
December 6th, 2012
Even with high-quality brass from Lapua, Norma, and RWS, occasionally you may find one or two cases per box which have a small flake or obstruction in the flash-hole. This will appear like a thin crescent on one side of the flash hole (see photo). You should inspect ALL new brass before loading to identify any pieces with a partially-obstructed flash hole. It’s a good idea to remove any flake or thin crescent left as an artifact of the flash-hole forming process. Because the flash-hole itself is normally centered and of the correct diameter, it is not necessary to ream the flash-hole to a larger diameter. All you really need to do is remove the small obstruction(s). This can be done quickly with inexpensive tools.
Use a Small Pin Vise to Remove Flash-Hole Obstructions
Folks have asked if there is a tool that can remove obstructions from a Lapua small, BR-sized flash hole without opening the hole size. The Lapua PPC/BR flash hole is spec’d at 1.5mm, which works out to 0.059055″. Most of the PPC/BR flash-hole uniforming tools on the market use a 1/16″ bit which is nominally 0.0625″, but these often run oversize — up to 0.066″.
If you want to just clear out any obstructions in the flash hole, without increasing the flash hole diameter, you can use an inexpensive “pin vise” with an appropriate drill bit. For $1.00, eHobbyTools.com sells a 1.5mm drill bit, item 79186, that matches the Lapua flash hole exactly. Other vendors offer a #53 pin vise drill bit that measures .0595″ or .060″ (depending or source). An 0.0595″ bit is close enough. You can find pin vises and these small-diameter drill bits at hobby stores.
For quite some time, Sinclair Int’l has sold a similar device for small (PPC and BR-size) flash holes. Like the new 07-3081 unit for large flash holes, the 07-3000 Reamer for small flash holes works from the outside, so it can index off the primer pocket. It reams to .0625″, and also costs $45.99. The standard dimension for Lapua 220 Russian and 6mmBR flash holes is 1.5mm or .0590″. This tool will permit standard-size decapping rods with .0625″ tips to work without binding. However, note that both Forster and Redding normally supply .057″ decapping pins with their PPC and BR dies. So, it is NOT necessary to ream your Lapua BR/PPC flashholes, unless you prefer to do so for uniformity. It IS, however, a good idea to check BR/PPC flash holes for burrs before loading the first time.
NOTE: If you purchase either the 07-3081 or 07-3000 Sinclair Flash Hole Reamer tools, we recommend you mic the cutter tip before you process a bunch of cases. Sometimes a tip comes through that is oversize. This will ream the flash holes larger than you may intend.
December 1st, 2012
You’ve heard of Heavy Metal, maybe even Heavy Water, but what about Heavy Sand? Every serious shooter should know about Heavy Sand for benchrest sandbags. Heavy Sand can weigh up to twice as much as ordinary silica sand (sold as “Play Sand”). By filling your rear bag with Heavy Sand rather than silica sand, you can nearly double the bag’s mass, and that can translate to better bag performance. A heavier bag resists movement and stays aligned better during recoil. If your bag moves during recoil, or becomes misaligned from shot to shot, that can alter your point of impact and open up your groups. Adding weight to your rear bag is a simple, cost-effective way to shoot more consistently, with greater overall accuracy.
Jason tested and compared four kinds of sandbag fillers: Zircon, Chromite, Riverbed Sand, and ordinary Play Sand. Zircon is the heaviest type of sand readily available to shooters, followed by Chromite. Zircon is 98% heavier than Play Sand, while the black Chromite sand is 94% heavier than Play Sand. Riverbed Sand, commonly sold in pet stores as “Reptile Sand”, is less dense, measuring about 55% heavier than Play Sand.
Increase Bag Weight Up to 10 pounds
Compared to silica sand, how much extra weight can Heavy Sand (Zircon, Chromite, Riverbed) add to your sandbag? Up to 10 pounds, depending on the size of your rear bag. Check the chart below for the specifics. By filling a standard bunny ear bag with Zircon (vs. silica sand), you can increase bag weight by about 5 pounds. A super-sized BigFoot bag can gain 10 pounds in overall weight when filled with Zircon as opposed to silica sand.
To learn more about Heavy Sand (and where you can buy it), read Jason’s comprehensive Sand Comparison Article. It includes photos of the different sand types and links to Heavy Sand vendors, such as R.W. Hart (Zircon) and Sinclair International (Chromite).
December 1st, 2012
Let’s say you’ve purchased a new scope, and the spec-sheet indicates it is calibrated for quarter-MOA clicks. One MOA is 1.047″ inches at 100 yards, so you figure that’s how far your point of impact (POI) will move with four clicks. Well, unfortunately, you may be wrong. You can’t necessarily rely on what the manufacturer says. Production tolerances being what they are, you should test your scope to determine how much movement it actually delivers with each click of the turret. It may move a quarter-MOA, or maybe a quarter-inch, or maybe something else entirely. (Likewise scopes advertised as having 1/8-MOA clicks may deliver more or less than 1 actual MOA for 8 clicks.)
 Reader Lindy explains how to check your clicks: “First, make sure the rifle is not loaded. Take a 40″ or longer carpenter’s ruler, and put a very visible mark (such as the center of an orange Shoot’N’C dot), at 37.7 inches. (On mine, I placed two dots side by side every 5 inches, so I could quickly count the dots.) Mount the ruler vertically (zero at top) exactly 100 yards away, carefully measured.
Place the rifle in a good hold on sandbags or other rest. With your hundred-yard zero on the rifle, using max magnification, carefully aim your center crosshairs at the top of the ruler (zero end-point). Have an assistant crank on 36 (indicated) MOA (i.e. 144 clicks), being careful not to move the rifle. (You really do need a helper, it’s very difficult to keep the rifle motionless if you crank the knobs yourself.) With each click, the reticle will move a bit down toward the bottom of the ruler. Note where the center crosshairs rest when your helper is done clicking. If the scope is accurately calibrated, it should be right at that 37.7 inch mark. If not, record where 144 clicks puts you on the ruler, to figure out what your actual click value is. (Repeat this several times as necessary, to get a “rock-solid”, repeatable value.) You now know, for that scope, how much each click actually moves the reticle at 100 yards–and, of course, that will scale proportionally at longer distances. This optical method is better than shooting, because you don’t have the uncertainly associated with determining a group center.
Using this method, I discovered that my Leupold 6.5-20X50 M1 has click values that are calibrated in what I called ‘Shooter’s MOA’, rather than true MOA. That is to say, 4 clicks moved POI 1.000″, rather than 1.047″ (true MOA). That’s about a 5% error.
I’ve tested bunches of scopes, and lots have click values which are significantly off what the manufacturer has advertised. You can’t rely on printed specifications–each scope is different. Until you check your particular scope, you can’t be sure how much it really moves with each click.
I’ve found the true click value varies not only by manufacturer, but by model and individual unit. My Leupold 3.5-10 M3LR was dead on. So was my U.S.O. SN-3 with an H25 reticle, but other SN-3s have been off, and so is my Leupold 6.5-20X50M1. So, check ‘em all, is my policy.”
From the Expert: “…Very good and important article, especially from a ballistics point of view. If a ballistics program predicts 30 MOA of drop at 1000 yards for example, and you dial 30 MOA on your scope and hit high or low, it’s easy to begin questioning BCs, MVs, and everything else under the sun. In my experience, more than 50% of the time error in trajectory prediction at long range is actually scope adjustment error. For serious long range shooting, the test described in this article is a MUST!” — Bryan Litz, Applied Ballistics for Long-Range Shooting.
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