A while back, Roy Bertalotto acquired a budget-priced Kimber 82G rimfire target rifle from the CMP. The Kimber comes with an oiled-wood stock that works fine for three-position training, but Roy wanted to shoot the gun for the bench. The original Kimber stock, with its narrow, radiused forearm, was not ideal for this purpose. Roy wanted a wide, flat fore-end, which is much more stable in the bags. Rather that spend hundreds on a new benchrest stock, Roy modified his Kimber’s original stock by slicing a section off the bottom of the stock and then replacing this with a 3/4″ X 2 3/4″ X 15″ piece of walnut.
WATCH Project Stages in Slide-Show Below:
Roy explains: “The modification I did on my Kimber 82G stock was done using a milling machine, hand planes, files, die grinder and sand paper. It can also be done with simple hand tools — it will just take longer. The first step is removing the wood on the bottom of the fore-end. This was accomplished in the milling machine. A scrap piece of 2X8 was mounted to the milling machine’s table and the surface milled to be perfectly flat. The Kimber stock was screwed to this 2X8 with two large screws and the bottom of the stock was milled flat. Once this was done, a piece of 3/4″ X 2 3/4″ X 15″ walnut was glued using West System epoxy to the cut out area. I use West System epoxy in boat building, but any good wood glue will work.”
After gluing the new bottom piece in place, Roy milled the sides to provide side flats with a radius to transition from the wider lower section to the narrower upper part of the fore-end. As a added enhancement, Roy contoured the rear of the fore-end to blend with the rear of the stock, adding what he calls “1965 Ford Mustang side scoops”. Roy then used a Die Grinder with a 1.5″ sanding wheel to modify the wrist area to provide more thumb relief.
Following the cutting, milling, gluing, and shaping, Roy sanded with 150 grit and 300 grit sandpaper before applying multiple coats of Tung Oil. Once the main stock was completed, Roy completed the project by crafting an extended buttplate from a couple pieces of 1/8″ aluminum and two 1.5″ aluminum tubes, “all polished to a slightly less than mirror finish”. NOTE: This metal buttplate assembly was made from scratch (other than the pad). This is not an aftermarket extension kit.
Overall the gun turned out very nicely. Log on to Roy’s RVB Precision webpage to learn more about this Kimber stock modification project, and view more photos of the building process.
Have you recently purchased a new scope? Then you should verify the actual click value of the turrets before you use the optic in competition (or on a long-range hunt). While a scope may have listed click values of 1/4-MOA, 1/8-MOA or 0.1 Mils, the reality may be slightly different. Many scopes have actual click values that are slightly higher or lower than the value claimed by the manufacturer. The small variance adds up when you click through a wide range of elevation.
In this video, Bryan Litz of Applied Ballistics shows how to verify your true click values using a “Tall Target Test”. The idea is to start at the bottom end of a vertical line, and then click up 30 MOA or so. Multiply the number of clicked MOA by 1.047 to get the claimed value in inches. For example, at 100 yards, 30 MOA is exactly 31.41 inches. Then measure the difference in your actual point of impact. If, for example, your point of impact is 33 inches, then you are getting more than the stated MOA with each click (assuming the target is positioned at exactly 100 yards).
How to Perform the Tall Target Test
The objective of the tall target test is to insure that your scope is giving you the proper amount of adjustment. For example, when you dial 30 MOA, are you really getting 30 MOA, or are you getting 28.5 or 31.2 MOA? The only way to be sure is to verify, don’t take it for granted! Knowing your scopes true click values insures that you can accurately apply a ballistic solution. In fact, many perceived inaccuracies of long range ballistics solutions are actually caused by the scopes not applying the intended adjustment. In order to verify your scope’s true movement and calculate a correction factor, follow the steps in the Tall Target Worksheet. This worksheet takes you thru the ‘calibration process’ including measuring true range to target and actual POI shift for a given scope adjustment. The goal is to calculate a correction factor that you can apply to a ballistic solution which accounts for the tracking error of your scope. For example, if you find your scope moves 7% more than it should, then you have to apply 7% less than the ballistic solution calls for to hit your target.
NOTE: When doing this test, don’t go for the maximum possible elevation. You don’t want to max out the elevation knob, running it to the top stop. Bryan Litz explains: “It’s good to avoid the extremes of adjustment when doing the tall target test.I don’t know how much different the clicks would be at the edges, but they’re not the same.”
Should You Perform a WIDE Target Test Too?
What about testing your windage clicks the same way, with a WIDE target test? Bryan Litz says that’s not really necessary: “The wide target test isn’t as important for a couple reasons. First, you typically don’t dial nearly as much wind as you do elevation. Second, your dialed windage is a guess to begin with; a moving average that’s different for every shot. Whereas you stand to gain a lot by nailing vertical down to the click, the same is not true of windage. If there’s a 5% error in your scope’s windage tracking, you’d never know it.”
Verifying Scope Level With Tall Target Test
Bryan says: “While setting up your Tall Target Test, you should also verify that your scope level is mounted and aligned properly. This is critical to insuring that you’ll have a long range horizontal zero when you dial on a bunch of elevation for long range shots. This is a requirement for all kinds of long range shooting. Without a properly-mounted scope level (verified on a Tall Target), you really can’t guarantee your horizontal zero at long range.”
NOTE: For ‘known-distance’ competition, this is the only mandatory part of the tall target test, since slight variations in elevation click-values are not that important once you’re centered “on target” at a known distance.
At the 2015 F-Class National Championships, nearly three-quarters of the F-Open shooters were using SEB coaxial front rests. And the man who makes them, Sebastian Lambang, was on the firing line too. Seb shot very well, finishing in second position in the F-TR division for the Saturday (Oct. 31) session. For those shooting F-Open or benchrest matches, Seb’s joystick rests really do represent the current state-of-the-art in front rest design. Courtesy of Seb, here are some photos that illustrate the “inner workings” of the SEB NEO Front Rest.
If you’ve ever wondered how a joystick front rest works, and how the parts go together, study the photos below. In addition, for those who use a NEO rest in competition, Benchrest Champion Mike Ratigan offers some PRO USER Tips that will help you get the best results from your NEO.
Unique Features of the SEB NEO Front Rest:
Lots of Travel — 43 MOA Vertical and 48 MOA Horizontal via joystick alone. The NEO offers more joystick travel than any other coaxial rest.
Variable Joystick Movement — The NEO is the only rest that can be configured for reverse action mode. That means you can optionally set it to lower the rifle with an up movement of the joystick if you prefer. (Standard setting raises rifle with up joystick movement.)
Rack & Pinion Risers — The NEO has dual support columns with Rack & Pinion system, offering a very broad vertical adjustment range.
Optional Counter-Weights — The NEO comes standard with a spring-loaded top mechanism to help hold up the rifle. Optional counter-weights allow you to reduce spring “pre-load”. Many people feel the counter-weights also allow a smoother, less jerky movement.
Reversible Base — The NEO’s base can be set-up with either the long leg in the rear or the long leg in the front. Putting the long leg in front gives more room under the rifle.
NEO Packs Flat — The SEB NEO is easily dismantled for transport, and can pack nearly flat. This is a big advantage when traveling.
Counter-weight Function and Calibration: “With the Seb NEO, equipped with the optional static counter-weight, the shooter can calibrate the counter weight to the rifle weight. The counter-weight is used to hold up the rifle. Clamping pressure of the sliding plates is NOT used to hold up the rifle like other coaxial rests on the market today. Other coaxial rests apply enough clamping force to the rest top mechanism sliding plates to resist the downward movement of the top when the rifle weight sets on the rest. This one feature of the Seb NEO almost completely eliminates bullets falling out of the bottom of your groups because the rest moved (or falls) down when you fired the rifle. This function is very important.”
On Hand Position: “I try to keep the palm of my hand grounded to the bench at all times. To do this at the closer distances, the handle will be laying flat (bend to the side) while shooting on the bottom of the target. To move to the top up (for right-handed shooters) I rotate the handle counter clockwise, which [raises the top] while maintaining my palm grounded to the bench.”
On Front Bag Fill: “Give some coarse sand blasting sand a try with the small stuff screened out. This will help reduce compaction from daily use.”
We’ve all heard the old adage: “Keep your powder dry.” Well, tests by Norma have demonstrated that even normal environmental differences in humidity can affect the way powders burn, at least over the long term. In the Norma Reloading Manual, Sven-Eric Johansson, head of ballistics at Nexplo/Bofors, presents a very important discussion of water vapor absorption by powder. Johansson demonstrates that the same powder will burn at different rates depending on water content.
Powders Leave the Factory with 0.5 to 1.0% Water Content
Johansson explains that, as manufactured, most powders contain 0.5 to 1% of water by weight. (The relative humidity is “equilibrated” at 40-50% during the manufacturing process to maintain this 0.5-1% moisture content). Importantly, Johansson notes that powder exposed to moist air for a long time will absorb water, causing it to burn at a slower rate. On the other hand, long-term storage in a very dry environment reduces powder moisture content, so the powder burns at a faster rate. In addition, Johansson found that single-base powders are MORE sensitive to relative humidity than are double-base powders (which contain nitroglycerine).
Tests Show Burn Rates Vary with Water Content
In his review of the Norma Manual, Fred Barker notes: “Johansson gives twelve (eye-opening) plots of the velocities and pressures obtained on firing several popular cartridges with dehydrated, normal and hydrated Norma powders (from #200 to MRP). He also gives results on loaded .30-06 and .38 Special cartridges stored for 663 to 683 days in relative humidities of 20% and 86%. So Johansson’s advice is to keep powders tightly capped in their factory containers, and to minimize their exposure to dry or humid air.”
Confirming Johansson’s findings that storage conditions can alter burn rates, Barker observes: “I have about 10 pounds of WWII 4831 powder that has been stored in dry (about 20% RH) Colorado air for more than 60 years. It now burns about like IMR 3031.”
What does this teach us? First, all powders start out with a small, but chemically important, amount of water content. Second, a powder’s water content can change over time, depending on where and how the powder is stored. Third, the water content of your powder DOES make a difference in how it burns, particularly for single-base powders. For example, over a period of time, a powder used (and then recapped) in the hot, dry Southwest will probably behave differently than the same powder used in the humid Southeast.
Reloaders are advised to keep these things in mind. If you want to maintain your powders’ “as manufactured” burn rate, it is wise to head Johannson’s recommendation to keep your powders tightly capped when you’re not actually dispensing charges and avoid exposing your powder to very dry or very humid conditions. The Norma Reloading Manual is available from Amazon.com.
Real-World Example — “Dry” H4831sc Runs Hotter
Robert Whitley agrees that the burn rate of the powder varies with the humidity it absorbs. Robert writes: “I had an 8-lb. jug of H4831SC I kept in my detached garage (it can be humid there). 43.5-44.0 gr of this was superbly accurate with the 115 Bergers out of my 6mm Super X. I got tired of bringing it in and out of the garage to my house for reloading so I brought and kept the jug in my reloading room (a dehumidified room in my house) and after a few weeks I loaded up 43.5 gr, went to a match and it shot awful. I could not figure out what was going on until I put that load back over the chronograph and figured out it was going a good bit faster than before and the load was out of the “sweet spot” (42.5 – 43.0 gr was the max I could load and keep it accurate when it was stored in less humid air). I put the jug back in the garage for a few weeks and I now am back to loading 43.5 – 44.0 gr and it shoots great again. I have seen this with other powders too.”
If you have two jugs of the same powder, one kept in a room in your house and one somewhere else where it is drier or more humid, don’t expect the two jugs of the same lot of powder to chrono the same with the same charge weights unless and until they are both stored long enough in the same place to equalize again.
Berger has released two important informational updates for its line-up of bullets. First, the Ballistics Coefficients (BCs) have been updated for the vast majority of bullets Berger sells. In addition, G7 model BCs are being provided for most of the bullets. You will want to use the updated BC data, which is based on actual testing of recent production lots of bullets.
Second, Berger is now providing a dual twist-rate recommendation for most bullets. Berger is now lists a “minimum” barrel twist rate as well as an “optimal” twist rate. To get maximum long-range performance from your bullets, use a barrel with the “optimal” rate of twist.
CLICK HERE for the latest Berger Quick Reference Sheets with updated BCs and new Optimal Twist Rates. Eric Stecker, Berger President says: “We have tested every lot of bullets produced in the last several years to bring you these updated numbers for all of our bullets.”
Ballistic Coeffificent (BC) Updates with G7 Data
Berger notes: “We have updated all of our Ballistic Coefficients to be even more accurate.
Prior to 2008, all of Berger Bullets’ BCs were calculated using a computer prediction. Early in 2009, we began measuring BCs with live-fire testing. As a result, Berger’s BCs were updated and G7 BCs were also made available. This represented a dramatic improvement in the accuracy of performance data at that time. Since 2009, the BCs assessed for Berger Bullets have not been updated. As part of our ongoing effort to provide shooters with the best information possible, Berger has been testing every lot of bullets produced for the last several years. The result is updated and highly accurate running averages of BCs for recent production lots.
Here are some of the Updated BC Values for popular Berger Target (Match) Bullets:
G7 Form Factor Addition
Berger also added the G7 form factor to the Ballistics Quick Reference Sheet. The analysis of form factors can be very useful when considering a bullet’s long range performance potential. Going by BC alone can be deceptive since BC includes the weight and caliber of the bullet. Form factor indicates how much drag the bullet has, which is a very important consideration for all bullets of all calibers.
NEW Dual Twist-Rate Recommendations
Recommended twist rates for bullets are commonly listed as a single value, such as 1:12” (one rotation in 12″ of barrel travel). This may be overly simplistic. There is a big gray area of marginal stability in which bullets can fly with good accuracy, but with a reduced (i.e. sub-optimal) Ballistic Coefficient. Recognizing this reality, Berger is now listing two twist rates for each bullet it makes. The first is the minimum twist needed for good accuracy, which Berger has always recommended. The second is the new optimal twist rate, which is the twist that will stabilize the bullet to a level which achieves its full performance (BC) potential. CLICK HERE For more information.
Can you guess what your next barrel will weigh? In many competition disciplines, “making weight” is a serious concern when putting together a new match rifle. A Light Varmint short-range Benchrest rifle cannot exceed 10.5 pounds including scope. An F-TR rifle is limited to 18 pounds, 2 oz. (8.25 kg) with bipod.
One of the heaviest items on most rifles is the barrel. If your barrel comes in much heavier than expected, it can boost the overall weight of the gun significantly. Then you may have to resort to cutting the barrel, or worse yet, re-barreling, to make weight for your class. In some cases, you can remove material from the stock to save weight, but if that’s not practical, the barrel will need to go on a diet. (As a last resort, you can try fitting a lighter scope.)
Is there a reliable way to predict, in advance, how much a finished barrel will weigh? The answer is “yes”. PAC-NOR Barreling of Brookings, Oregon has created a handy, web-based Barrel Weight Calculator. Just log on to Pac-Nor’s website and the calculator is free to use. Pac-Nor’s Barrel Weight Calculator is pretty sophisticated, with separate data fields for Shank Diameter, Barrel Length, Bore Diameter — even length and number of flutes. Punch in your numbers, and the Barrel Weight Calculator then automatically generates the weight for 16 different “standard” contours.
Calculator Handles Custom Contours
What about custom contours? Well the Pac-Nor Barrel Weight Calculator can handle those as well. The program allows input of eight different dimensional measurements taken along the barrel’s finished length, from breech to muzzle. You can use this “custom contour” feature when calculating the weight of another manufacturer’s barrel that doesn’t match any of Pac-Nor’s “standard” contours.
Nightforce Optics has just launched a new monthly newsletter. This free, subscription-based digital publication will offer information on optics, target shooting, hunting, and other topics of interest. The debut October issue, released this week, features match reports, tactical shooting hold-over advice, plus a TECH TIP explaining Parallax.
PARALLAX – What is it and Why is it important?
What is Parallax?
Parallax is the apparent movement of the scope’s reticle (cross-hairs) in relation to the target as the shooter moves his eye across the exit pupil of the riflescope. This is caused by the target and the reticle being located in different focal planes.
Why is it Important?
The greater the distance to the target and magnification of the optic, the greater the parallax error becomes. Especially at longer distances, significant sighting error can result if parallax is not removed.
How to Remove Parallax
This Nightforce Tech Tip video quickly shows how to remove parallax on your riflescope.
While keeping the rifle still and looking through the riflescope, a slight nod of the head up and down will quickly determine if parallax is present. To remove parallax, start with the adjustment mechanism on infinity and rotate until the reticle remains stationary in relation to the target regardless of head movement. If parallax has been eliminated, the reticle will remain stationary in relation to the target regardless of eye placement behind the optic.
If you want to subscribe to the Nightforce Newsletter, CLICK HERE to open the Newsletter then click the green “Join Email List” button at the top of the page.
Gun guys are always shipping stuff around the country — whether it’s a barrel to be chambered, or a scope that needs to go back for warranty repair. Or maybe you’ve sold some bullets or reloading dies you no longer need. To ensure your precious packages get to their destination in one piece, it’s important to take precautions when boxing up your items. And by all means insure packages for full value — even if your packaging is perfect, there is always the possibility that your shipment might be lost altogether. Sadly, that can happen, no matter which carrier you choose: Fedex, UPS, or the U.S. Postal Service (USPS). Here are some tips for shipping gun stuff — we explain how to pack items properly and how to minimize the risk of loss.
Tips for Shippers
Dennis Haffner from McGowen Precision Barrels offers some advice on how to avoid damage when shipping gun parts or other valuable or heavy items. Dennis explains:
“First, I started double-packing the contents and in many cases double-boxing. I spend a fortune on heavy-reinforced shipping tape. If the contents are loosely packed, the package is going to get crushed. On real important items or delicate items, wrap the content in plastic and spray the inside void areas with non-expanding foam. They make shipping foam just for this. This method really works. Since I started paying more attention to packaging, I have just about wiped out my issues with all three companies (Fedex, UPS, USPS). Yes, I hate doing it, but in the long run for us, it’s cheaper.
Bullet shipments are the worst — a shipment of 500+ bullets can destroy a cardboard box. I have ordered bullets from individuals who put them in baggies and filled the remainder of the box with foam peanuts. That is not going to work. Any piece of metal, including a die, will puncture a cardboard box, or destroy a padded envelope. Just look at the tracking information and imagine your package bouncing around in the back of the shipping truck, probably under many other packages. My advice is to NEVER use padded envelopes. Barrel nuts or recoil lugs will most likely never make it.
ORM-D items are required to be shipped in heavily-reinforced, double-walled containers. The packages still get a little damage, but the contents usually survive.
How do shipments get damaged? Consider this — one of the shipping companies this year flipped (overturned) one of our new CNC machines (which rendered it useless). Maybe your small packages were in the same delivery truck as my CNC machine. I wonder how many little boxes were crushed underneath it.
As for USPS flat rate boxes — you would not believe what people try to stuff in these boxes. USPS finally put a weight limit on the boxes — they had to. I sometimes take my delicate items packed in an envelope or small box. I spray foam in a larger flat rate box and insert the smaller package, then fill the remainder of the void with foam. It works, and part usually arrives undamaged.”
Shipping Rifle Barrels (PVC Tube and Tennis Ball Method)
A new match-grade barrel can cost $350 or more, and it might take six months (or more) to replace it, given the current wait time with top barrel-makers. So, you don’t want your nice new tube to get damaged in transit. Forum Member Chuck L. (aka “M-61″) offers these tips for shipping rifle barrels:
“Packing a barrel can be a problem. Here’s a shipping method that won’t stop lost shipments but so far has stopped damage. Get a PVC pipe (of size appropriate to your barrel) with fitted caps for each end. Attach a cap to one end. Tape the barrel threads and tape over the muzzle. Then drop one standard tennis ball into the pipe. Place barrel in pipe. Next add whatever peanuts or foam you can jam in to support the barrel on the sides. Then place a second tennis ball into the opposite end of the PVC pipe. (So now you have a tennis ball on either end of your barrel.) With everything secure inside, attach the upper cap and tape it down securely. With this packing procedure, when the carrier launches the pipe like a javelin, at least the barrel will not come through like a spear and be gone. Label the pipe with very large address labels so no one suspects it’s just garbage laying around. This procedure may seem ridiculous but it has worked for me. Oh and definitely get insurance. If your item is insured, the shippers will look harder to find it.”
Editor’s Note: Fedex also makes a triangular-profile cardboard shipping box. This 38″ x 6″ x 6″ x 6″ Fedex Tube (designed for blueprints and posters) is free for the asking. For most barrels, there should be enough clearance to hold your PVC tube (with barrel packed inside tube). However, don’t ship the barrel inside the cardboard box by itself. Cap and pad the ends and bubble wrap it heavily, or better yet, use the PVC tube method described above, with the PVC tube inside the box.
Dave Diana is a clever fellow. He not only fabricated his own wireless Target Cam system, but he invented a mount that places the receiver/monitor unit conveniently next to his bench rifle. The hooded view-screen actually mounts to his SEB front Rest via a bracket. The monitor unit includes wireless receiver and a short directional antenna (see below):
Dave says his new CCTV monitor bracket on the SEB NEO rest is “working as planned”. However, after taking these photos, Dave did make a modification. Dave explained: “I found moving the monitor over to the left-hand side was more shooter-friendly. I can stay in a natural shooting position, look at the screen, see my windflags and shoot with little movement. The next task is to add a coffee cup holder somewhere to house my group tightener double expresso!”
Target Cam Monitor Has Built-In Receiver
Dave built a very nice system. He tells us: “The security camera is a 27x power zoom camera housed in a weather proof case that also houses the wireless transmitter. The monitor has a built-in receiver, and I am running spiral polarized antennas on both ends. The system will run all day long on the waterproof-cased, game-camera batteries.”
Here are the internals of the wireless camera system. Note the antenna at right.
Here is the entire system, with monitor/receiver placed conventionally on a tripod. Batteries are housed in waterproof plastic cases.
Ask 10 shooters about barrel cleaning and you’ll get 10 different opinions. This reflects that fact that different fouling problems demand different solutions. For example, solvents that work well for copper may not be the best for hard carbon (and vice-versa). To come up with the right solution, first you must understand the nature of the fouling in your barrel.
The debate about the proper care of a match barrel is a hot one, spiked with folklore and old wives’ tales, Lohman said. He and his staff set out to set the record straight: “We tried to interject some science into the discussion of cleaning a match barrel,” he explained. In his article, Lohman writes:
Why worry about a little barrel fouling when the throat is subjected to a brutal 5,600° F volcano at 55,000 PSI? To investigate these and other questions about taking care of a match barrel, we spoke with a dozen experts and share their knowledge in this first of a series of articles.
After listening to folks who shoot, build barrels or manufacture cleaning solvents for a living, we concluded that even the experts each have their own unique recommendations on how to care for a match barrel. But they all agree on one thing — the gun will tell you what it likes best. Because the life expectancy of a match barrel is about 1,500 to 2,500 rounds, the objectives of cleaning one should include: preserve accuracy, slow the erosion, and remove fouling — all without damaging the gun. This article doesn’t claim that one cleaning method is better than the next. Rather, we set out to interject a little science into the discussion and to share some lessons learned from experts in the field.
For more Shooting Sports USA articles, visit www.ssusa.org.
John Krieger Interview with AccurateShooter at SHOT Show: