As the practical/tactical game has evolved, with low recoil and high accuracy becoming ever more important, many top competitors have moved to smaller cartridges such as the 6mm Dasher and its parent, the 6mmBR Norma. These cartridges deliver outstanding accuracy plus good barrel life. However, the “short, fat” 6BR/Dasher design doesn’t feed optimally in magazines designed for the .308 Win family of cases. Yes you can modify your own magazines (Mag Mod HERE), or buy a pricey conversion kit, but now there is a turn-key solution from MDT (Modular Driven Technologies).
MDT’s 6mm BR magazine fits the parent 6mmBR cartridge and all the popular varients including the 6 BRA, 6 Dasher, and 6 BRX. MDT says this new 12-round magazine is a “one-step solution [delivering] smooth, reliable feeding for the most popular rifle cartridges in precision rifle competitions.”
MDT built this AICS-pattern mag for PRS/NRL competitors and anyone wanting to run 6mmBR-family cartridges in mag-fed actions: “The limiting factor for competitors running 6mm BR variants has been feeding. Until now, the only option has been to purchase an AICS-pattern magazine plus an additional kit to make the magazines work with the shorter cartridges. This solution costs upwards of $100 or more and can require additional tuning to work in most rifles.”
The MDT 6mm BR mag has a maximum internal length of 2.580″, which accommodates pretty much any 6mm bullet you’d want to use. These MDT magazines are crafted from quality steel, nitride-treated, then black Cerakote finished inside and out. To reduce friction between cartridge and magazine body, MDT added two internal ribs which provide a smooth transition from double stack to single-feed.
Magazine Conversion — Use .308 Win Mags with Modified Followers
A decade ago we showed our readers how to modify .308 Win magazines to feed the 6mmBR cartridge efficiently. This procedure, explained by Texas gunsmith, Mike Bryant, is easy to do with simple tools. You can modify most standard magazines, both internal-style and detachable style. CLICK HERE for full, step-by-step magazine conversion article.
The basic procedure involves trimming the rear of the magazine, and creating a rear stop with a block from a Remington .223 magazine. Next the .308 Win magazine follower is shortened and beveled. Some guys tweak the feed lips a bit, but this may not be needed. Many of our readers have performed this simple magazine modification and report their rifles feed quite reliably. One reader, who converted a 7mm-08 hunting rig into a 22 Dasher varmint rifle, tells us his modified mag feeds flawlessly.
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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
At our Southern California test range some years ago, we 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.
Barrel Velocity Variance
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. (Click Here for results of 6mmBR Barrel Length Velocity Test).
IMPORTANT: 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, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, 30-06, or .338 LM 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. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]
When you complete a new 6mmBR rifle, it’s definitely smart 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.
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If your local shooting club wants to attract new members, and provide a new form of competition, consider starting a series of groundhog (varmint) matches. These can employ paper targets, metal silhouette-style targets, or both. Groundhog matches are fun events with straight-forward rules and simple scoring. You don’t need to bring windflags or load at the range, so a Groundhog match is more “laid back” than a registered Benchrest match. Normally there will be three or four rifle classes, so you can compete with a “box-stock” factory gun, or a fancy custom, as you prefer. Many clubs limit the caliber or cartridge size allowed in varmint matches, but that’s just to protect reactive targets and keep ammo costs down. In this article, Gene F. (aka “TenRing” in our Forum), provides a basic intro to Groundhog matches, East-Coast style.
Groundhog Matches Are Growing in Popularity
Though Groundhog matches are very popular in many parts of the country, particularly on the east coast, I’ve found that many otherwise knowledgeable “gun guys” don’t know much about this form of competition. A while back, I ordered custom bullets from a small Midwest bullet-maker. He asked what type of competition the bullets would be used for, and I told him “groundhog shoots”. He had not heard of these. It occurs to me that perhaps many others are unfamiliar with this discipline.
Groundhog matches have grown rapidly in popularity. There are numerous clubs hosting them in Pennsylvania, Maryland, and Delaware, as well as other venues. They are usually open to the public. Most Eastern clubs have five to twenty cement benches, and overhead roofs. At this time, there is no central source for match schedules. If you’re interested in going to a groundhog match, post a query in the AccurateShooter Forum Competition Section, and you should get some info on nearby opportunities.
How Matches Are Run — Course of Fire and Scoring
Unlike NRA High Power Matches, there is no nationwide set of standard rules for Groundhog matches. Each club has their own rules, but the basics are pretty similar from club to club. Paper groundhog targets are set at multiple distances. There are normally three yardages in the match. Some clubs place targets at 100, 200, and 300 yards. Other clubs set them at 200, 300, or 400 yards. At my club in Shippensburg, PA, our targets are placed at 200, 300 and 500 meters.
The goal is to score the highest total. The paper targets have concentric scoring rings. The smallest ring is normally worth ten points while the large ring is worth five points. The course of fire varies among the various clubs. Most clubs allow unlimited sighters and five shots on the record target in a given time period. Only those five shots on the scoring rings are counted, so that with three yardages, a perfect score would be 150 points. Tie breakers may be determined by total number of dead center or “X” strikes; or, by smallest group at the farthest distance.
Types of Rifles Used at Groundhog Matches
The same benchrest rigs found at IBS and NBRSA matches can be utilized (though these will typically be put in a ‘custom’ class). Though equipment classes vary from club to club, it is common to separate the hardware into four or five classes. Typical firearm classes can include: factory rifle; deer hunter; light varmint custom (usually a limit of 17 lbs.with scope); and heavy varmint custom (weight unlimited). Some clubs allow barrel tuners, others do not. Scope selection is usually unlimited; however, some restrict hunter class rifle scopes to 20 power. Factory rifles usually cannot be altered in any way.
Good, Simple Fun Shooting — Why Groundhog Shoots Are Popular
Forum member Danny Reever explains the appeal of groundhog matches: “We don’t have a governing organization, or have to pay $50 a year membership just to compete in matches. Sure the rules vary from club to club, but you adapt. If you don’t like one club’s rules, you just don’t shoot there. It’s no big deal.
There are no National records, or Hall of Fame points — just individual range records. If you want to shoot in BIG matches (with big prizes), there is the Hickory Ground Hog Shoot among others. If competition isn’t your bag, many clubs offer mid-week fun matches that you can shoot just for fun. You shoot the same targets but with a more relaxed atmosphere with no time limits.
The best part is you don’t have to shoot perfect at every yardage. You always have a chance because in this sport it really isn’t over until the last shot is fired. Typically ALL the entry money goes to the host club, with much of the cash returned back to the shooters via prizes. Junior shooters often shoot for free, or at a reduced rate. The low entry cost also encourages young guys to get involved who don’t have $4000 custom rifles or the money to buy them.
There isn’t a sea of wind flags to shoot over or to put up and take down. If the range has a couple of flags so much the better, but after all it is a varmint match. No pits to spot shots and slow things down either. If you can’t see your hits through your rifle scope or spotting scope well you are in the same boat as everybody else. That’s what makes it interesting/ sometimes frustrating!
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This week we return to our 6mmBR.com roots with an article on David Bergen’s slick 24″ Drop-Port Viper. This was one of the first 6BR rifles we featured. David, who hails from Belgium, developed this project over many months, and the gun proved to be a true tack-driver, with the ability to group in the Ones, even with the heavy boat-tail bullets. David talks about the build and his reloading methods while action designer Jerry Stiller provides technical insights into the design features of his Viper action.
It was a long journey looking for the perfect custom action to build my new rifle. I searched the internet and visited various forums. I even re-read all my old Precision Shooting magazines to find what I was looking for. One evening I conferred by telephone with Mr. Jerry Stiller of Stiller’s Actions in Texas. He patiently answered all my questions. That moment I decided that I wanted a Viper Drop-Port action. [Editor: Sadly, the Viper Drop-Port is no longer in production.]
Component Selection At the heart of this gun is a Viper action. This medium-sized action can handle cartridges from a small BR up to a 6.5-284. (Stiller’s smaller Cobra action is for PPC and BRs only.) The Viper is milled from aluminum. This keeps weight down while still allowing Vipers to have a large bedding surface like a Stolle Panda.
At first I was a bit sceptical about the aluminum’s toughness, but Mr. Stiller informed me that the action is the perfect marriage between steel and aluminum. The bolt is hard-chromed and the action body is hard-anodized. This gives it two surfaces that resist wear and make an already-slick action even slicker. Stainless steel is used for all the heavy-stress points including barrel threads, locking lugs, and the rear camming surface. The bolt is made of steel with a very light, small-diameter firing pin to prevent primer piercing with heavy loads. Everything is held very concentric to the bore axis. The Viper is a very smooth action mainly because the design and the precise machining of the camming surfaces. Combined with optimal bolt-lift timing, this gives a smooth action. Stiller also keeps the tolerances very tight on these actions, though they are as fast-handling as any you can buy. The trigger is of course a Jewell BR model.
The rifle is chambered in 6mmBR Norma, my favorite cartridge. I have two HV-contour Shilen match barrels, both with 1 in 8″ twists and finished lengths of 24 inches. The chamber has a .266″ neck so neck-turning is necessary. Freebore is .060″ but combined with a 1.5° throat angle this lets me seat a wide range of bullets from 58 grains up to 107 grains.
The stock is a McMillan Edge with moulded-in gray and black marble swirl. I specified 60% black and dark and light gray both at 20%. I went with the Edge stock because I was always pleased with McMillan products and because it had a very low center of gravity. I wanted the barrels very low in the stock because I think it makes the gun track better.
Details of the Drop-Port–with VIDEO! The visible part of the Drop-Port is a cartridge-sized cut-out in the floor of the action. This tapers into a funnel shape that lets the spent case fall nose-first through a single hole in the underside of the stock. The Drop-Port is carefully sized so that empty brass will fall through from gravity but a loaded round won’t. I’ve found that getting a BR case to eject 100% reliably in a standard action is not easy. The round is short and fat so it clears the chamber too early and the ejector pushes the cases out the extractor too fast. This can result in an empty case sitting in your action, no longer held by the extractor. Needless to say, this can slow you down during a stressful competition. When you get a Drop-Port you can forget all those problems.
Failure to eject is NOT going to happen with a Drop-Port. The system just works every time, and it’s FAST. Right-Click on the Media Player image and “Save As” to download a video (6.9 megs) showing me cycling the action during live fire.
One smart feature of the Drop-Port is the extractor location. A Remington extractor is located at the bottom of the bolt. This way the case is supported by the extractor until the front of the case lines up with the cut-out in the action. At that moment the front of the case tilts down and the rim slips out of the extractor. In the stock there is a funnel which collects the case. The case drops out of the rifle through a single small hole in front of the trigger guard.
Building an Accurate Load Tools and Recipes I start with new Lapua cases and after full-length sizing I trim them with a Wilson trimmer. Then I turn the necks for a .264″ neck diameter with a Lapua 105 seated in the brass. After fire-forming I use a “semi-custom” Harrell’s full-length sizing die with bushing. I use a .262 bushing with the moly-coated bullets. This Harrell’s die is the best I ever used — it gives very low run out. [Editor’s Note: Harrell’s stocks a number of dies with various internal dimensions. You send them three fire-formed cases and they’ll pick out a die that fits your brass the best. The cost is very reasonable.] Overall the excellent concentricity I’m seeing with my rounds is a combination of a superb chambering job, a neck-turned Lapua case and the Harrell’s sizing die. The die is supplied with a brass bushing that allows you to measure the amount of sizing you are doing.
For seating I use both a Wilson inline seater (hand die) and a Forster seating die that threads into a press. The latter gets the most use because I find it easier to use. Run out with both is around 0.001″ or better measured on the bullet.
Load development was very easy. I started with Varget and all loads … shot well. Vihtavuori N150 also shot very well with… moly-coated Lapua 105s. To my delight, the light bullets are also shooting very well in the 1:8″ twist. Nosler Ballistic Tips are giving very good results with a case full of N140. I’ve also tried N150, N540 and AA 2520. For all loads I’ve been using CCI BR4. Bullets are seated well into the lands with square marks showing. This gives an overall length around 59 mm (2.32″), depending on the bullet used.
Shooting the Rifle–How It Performs The rifle is very easy to shoot and it is very accurate, but it had some drawbacks in the beginning. First there is the stock. It is designed for bench shooting and on a table it does this very well. I use a Caldwell front rest and a Protektor rear bag. When shooting prone I’ll also use the rest but the cheek weld is not ideal (the Edge was optimized for free recoil shooting from the bench). The rings that are supplied with the action are rather high. I looked around and found some that were lower. This made shooting easier, but I still wasn’t satisfied. The gun was a bit nose-heavy. There is a weight system built into the stock, but it wasn’t enough to bring the gun in balance. I like the balance point to be just in front of the receiver ring. So I cut the rear off the stock and put in a larger tube and turned some weights to put in it. I also made up an aluminum butt plate. Then I installed a Harrell’s brake to cut recoil to a minimum. With these modifications, the rifle is now shooting the way I want. I think the Edge stock is a very good design for benchrest shooting but for prone shooting it has some shortcomings. I think the MBR is a better stock for shooting prone.
Muzzle Brake–Less Recoil, Same Excellent Accuracy After testing the barrel with different loads, I decided to put a brake on one barrel. Most of my guns are muzzle-braked and since I had two virtually identical barrels, I put a Harrell’s brake on one. The barrel had to be threaded to mount the brake and here I was a little concerned–I remembered the advice to “never mess with a winner”. The un-braked barrel was ultra-accurate and I was curious whether the process of fitting the brake might affect the accuracy.
Thankfully, my worries were unfounded. My targets showed no loss of accuracy — there was no evidence that the brake had caused any changes (except as to recoil). I have wondered though, perhaps the brake makes the gun more shootable and in that way compensates for some small accuracy loss that may be there? Whatever the case, the gun shoots just as tight as before, except now it’s a lot more user-friendly with less muzzle hop and less “push” on recoil.
This Rifle Literally Shoots Bug-Holes
And now I come to the end of the story. One day when testing the rifle at 100 meters (with brake installed), I spied a fly on the target. Well now, I thought, here is an interesting “precision shooting” challenge. I put the crosshair on the fly, squeezed the trigger, and the fly was history.
One shot, one kill. Now THAT is impressive precision. If you look closely you’ll see what’s left of Mr. Fly around the bullet hole. Or “bug-hole” as you Americans would say. This kind of performance is a real confidence-booster for the trigger-puller, let me tell you.
The Drop-Port — Simple Yet Advanced
Jerry Stiller tells us: “The drop-port ejects the case out the bottom of the action using only gravity. No ejector plunger is required so the system is as foolproof as anything can be. (A normal spring-loaded ejector creates an uneven load on one side of the case head.) Unlike other ejection systems, micro-ports etc., a Drop-Port doesn’t require tuning or adjusting, and just works. Many top shooters tell us they can cycle rounds faster with a Drop-Port action than with any other design.”
“The engineering of the Viper reflects some key design objectives. I wanted it to be able to fit standard commercially available stocks and have a barrel fit-up that was well known in the industry. I liked the idea of the larger bedding area and higher stiffness of the aluminum actions, so I chose the Panda footprint and barrel tenon for the Viper. I also made some changes to what was available at the time to make the product better. I used a smaller diameter firing pin to eliminate primer piercing, hard anodized all the aluminum parts for corrosion resistance and to make the surface hard and slick. The bolts are also coated for the same reasons.
Report by Craig Arnzen, Area 419
As the PRS and other tactical/practical competitions continue to grow, a guy tends to wonder, just how good are the top competitors? And what are they actually doing (and viewing) as they complete a stage? Well, a great video from the new Long Range Precision Shooters YouTube Channel let us see what the best in the sport see through their scopes when they shoot.
This video features Dave Preston, 2015 National Champion and perennial powerhouse, shooting the PRS Skills barricade. Dave Preston is widely considered the best in the nation running this PRS stage. Dave nearly always shoots 100% with the fastest recorded time. In this video you’ll see him successfully engage all eight shots in under 43 seconds — that’s crazy fast. This includes a POV sequence (4:35 time-mark) showing the actual view through Dave’s scope as he completes the stage.
Watch this video! Dave offers excellent advice on gun-handling and body positioning for barricades. Listen to what he says and you WILL shoot better.
This video features the PRS Skills Barricade, an 8-round, 4-position stage featured at the majority of PRS matches throughout country. It’s called a “Skills Stage” as it is run the same way at every national match and gives shooters the ability to compare skill levels based on hit percentage and speed.
The target is a 10″ plate at 400 yards. There are four different positions, with two shots each. Most people run this stage in about 70 seconds, some in the mid-60s, the greats in the high 50s, and Dave does it in the low 40s… mighty impressive!
The Right Gear Aids Stability and Lets You Shoot Faster
Let’s also take a look at two pieces of gear that really helped Dave Preston get stable and shoot fast.
1. BARRICADE BAG — To Get Stable, Really Stable
In the video Dave is using a Solo Sac from Short Action Precision This bag was designed by USMC Solomon Mansalala, and $5 of every purchase goes to help the Marine Scout Snipers buy gear. It’s a very soft/dense bag and is popular at matches.
The other bag that sees a LOT of use, and is far and away the most used, is the patented Gamechanger Bag from Reasor Precision Solutions and Armageddon Gear.
2. MUZZLE BRAKE — To Make Your Follow-Up Faster
You’ll notice that in the video the rifle is very steady through firing, even though he is not applying a lot of pressure to the rifle. Dave is using a Hellfire Muzzle Brake from Area 419. Combined with the soft-recoiling 6mmBR cartridge he is able to spot his impacts and make adjustments, and can also make very fast follow-up shots as his rifle hasn’t bounced way off target.
More Long Range Precision Shooters Videos Coming Soon
I think this series from Long Range Precision Shooters (LRPS) will be a good one. They already have a couple more videos ready to release including one with 2018 King of 2 Miles Champion Robert Brantley. CLICK HERE for the LRPS YouTube Channel.
This TECH TIP brought to you by Area 419
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Here’s something you’ve probably never seen before — a single-shot, bolt-action pistol chambered for the 6mm BR Norma cartridge. Featured as one of our Guns of the Week a while back, this Green Machine is a Savage Striker upgraded by Chuck G. from Arizona, a self-described “Savage Maniac”.
Chuck transformed this Savage Striker single-shot from a ho-hum .308 into a reliable half-MOA precision 6BR that can run with accurized rifles all the way out to impressively long ranges. Here we provide highlights from our original article. Click the link below to read our full Savage Striker article, which is three times longer than this story, and has more photos, plus videos and a detailed load development section.
The Striker Project — Pursuit of Precision, by Chuck G.
I didn’t even know Savage Strikers existed until I saw one for sale on Gunbroker.com. I snagged it with a $400 bid. My idea was to build an accurate, long-range pistol on a pauper’s budget. As purchased, the Striker had a .308 barrel with an unknown round count, the standard center-grip, black synthetic stock, an odd two-piece custom brake, and an old Burris 4X pistol scope in a Conetrol 2-piece ring set. The trigger was very heavy, 6-8 lbs I’d estimate, with a lot of take-up and over-travel.
Initial Disappointments — Too Much Recoil, Poor Accuracy
My initial attempts to get the Striker to shoot well at even 100 yards were disappointing. I was never able to get better than a 3″, 5-shot group at 100. Not what I was looking for. Being used to benchrest triggers, the pull on this one was hard for me to manage. The gun would roll around on any type of front rest I had, and from a cement bench on a bipod it would jump about 18 inches up and sideways with every round. Not being used to this type of gun, I found the recoil and muzzle blast to be unsettling. It was hard not to flinch. I started off using my 1K .308 rifle load, 175 SMKs over 44 grains of Varget. That probably would have knocked the hell out of a deer, but it wasn’t much fun to shoot from the bench.
New Caliber, New Barrel — Way Better Accuracy!
I decided to rebuild the Striker in a caliber that would be more fun to shoot. 6mmBR was an obvious choice for all the usual reasons–good brass, wide choice of match bullets, easy to load, low recoil, very accurate, and relatively cheap to shoot. As part of a SavageShooters.com group buy, I ordered a 15″, SS match grade, 3-groove, heavy varmint contour, 10-twist barrel from Pac-Nor. To set the freebore, I provided Pac-Nor with a dummy case with an 88gr LD Berger bullet seated to use as a guide. Total delivered price was $340 chambered and threaded for a muzzle brake from JP Rifles.
When I bought it, the Striker, with factory .308 barrel, shot 3″ groups at 100. Now, with a Pac-Nor 6BR Match barrel, 3″ fore-arm plate, upgraded trigger, 24X scope, and match bullets, the gun consistently groups 1/2″ or better at 100 yards. What a transformation!”
Striker Project — Mission Accomplished
With further load development and bench practice, the gun is showing even more accuracy potential. Using a 24X target scope, the Striker has delivered 5-shot groups in the 3s and 4s during recent range visits. All in all, I’m very satisfied with the project. I ended up with an accurate, fun-to-shoot gun for under $1,000 including scope, paint, and bedding materials.
Stock Modifications
While waiting for the barrel I started working on the stock. As virtually no aftermarket stocks were readily available for the center-grip Striker, I decided to rebuild the standard black synthetic stock. The grip fit my hand poorly so I worked it over with a Dremel tool and sandpaper, built up the grip with Bondo, filled in some holes and bedded the action using Devcon Plastic Steel. This was my very first attempt at these tasks so progress was slow. Once I had re-shaped the stock, I sprayed five coats of “John Deere” green topped by several coats of auto clear. It came out surprisingly well considering I had never painted a stock before. I had originally planned to build up the fore-end to 3″ wide using Bondo but later decided to just use a Sinclair Benchrest Adapter that I had on hand.
Chuck notes: “I’m really pleased with the C & J one-piece Rest. It’s solid, heavy, and well-designed. There is no real need for a windage top; small adjustments are easily made by slightly shifting the pistol butt. Elevation adjustments are positive and once the pistol is set up on this rest NOTHING moves.”
Jonathan Ocab, a High Power shooter from California, had gunsmith Doan Trevor install a Sako-style extractor in the Rem 700 bolt in Ocab’s 6mmBR Eliseo R5 tubegun. Jonathan produced an excellent video showing how the Sako extractor improves the ejection of the short, fat 6mmBR cartridges in his rifle. Jonathan’s video demonstrates 6mmBR case ejection with an unmodified Rem 700 factory bolt versus a factory bolt fitted with a Sako-style extractor.
Johnathan explains: “Note how even when slowly operating the bolt, the bolt with the Sako extractor easily ‘kicks’ out the brass on ejection with minimal chance of operator error resulting in a failure to extract. While the unmodified bolt has issues ejecting brass on slow operation, it will eject if the operator pulls the bolt back quickly (fast and with some force).
While a Sako-style extractor isn’t an absolute necessity, this video shows the definite improvement this modification provides. For short cartridges like the 6mmBR, this is very useful. This modification is highly recommended for competition shooters, especially High Power competitors who seek improved function in rapid-fire stages. This modification is fairly inexpensive and any competent gunsmith should be able to perform the work (usually under $100 with parts and labor).”
EDITOR’s NOTE: In his video, Jonathan deliberately worked the unmodified Remington bolt slowly to show how the standard Rem extractor can struggle with short fat cases like the 6mmBR. In fact, when you work a standard, unmodified bolt more quickly, the extraction can be much more positive. Cycling the bolt with more “snap” provides more energy to eject the cases. We have run an R5 Tubegun chambered in 6mmBR with an unmodified Rem 700 bolt (no SAKO extractor), and the extraction was reliable, provided the bolt was worked quickly.
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At the request of many Forum members, we’re reprising this archived video from past IBS 600-yard Shooter of the Year Samuel Hall. Without a doubt, Sam is one of the best mid-range benchrest shooters in the nation. While the video quality is rough (to say the least), Sam’s offers plenty of tips you can “take to the bank”. Even if you don’t shoot competitively, the techniques described here can improve your accuracy when shooting from a bench.
2008 IBS 600-yard National Champion Samuel Hall has prepared a 9-minute VIDEO showing his techniques for shooting from the bench. Sam covers a number of topics including bag set-up, body position, bolt manipulation, and loading skills. He also explains the importance of having a relaxed, comfortable posture and keeping your head in the same position shot to shot.
If you’re serious about accurate benchrest shooting, at ANY distance, you should watch this video. Sam’s tips can really help you. We guarantee it. While the video itself is grainy and wind noise affects the audio, you can still glean many great points from the video. From minute 8:00 on Sam shoots a 5-shot string on camera with his BAT-actioned, Leonard-stocked 6BR. Though he was fighting 20-mph winds Sam achieves a half-inch group at 200 yards. Quarter-MOA in such conditions is good shooting.
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When a rifle isn’t shooting up to it’s potential, we need to ask: “Is it the gun or the shooter?” Having multiple shooters test the same rifle in the same conditions with the same load can be very revealing…
When developing a load for a new rifle, one can easily get consumed by all the potential variables — charge weight, seating depth, neck tension, primer options, neck lube, and so on. When you’re fully focused on loading variables, and the results on the target are disappointing, you may quickly assume you need to change your load. But we learned that sometimes the load is just fine — the problem is the trigger puller, or the set-up on the bench.
Here’s an example. A while back we tested two new Savage F-Class rifles, both chambered in 6mmBR. Initial results were promising, but not great — one gun’s owner was getting round groups with shots distributed at 10 o’clock, 2 o’clock, 5 o’clock, 8 o’clock, and none were touching. We could have concluded that the load was no good. But then another shooter sat down behind the rifle and put the next two shots, identical load, through the same hole. Shooter #2 eventually produced a 6-shot group that was a vertical line, with 2 shots in each hole but at three different points of impact. OK, now we can conclude the load needs to be tuned to get rid of the vertical. Right? Wrong. Shooter #3 sat down behind the gun and produced a group that strung horizontally but had almost no vertical.
Hmmm… what gives?
Shooting Styles Created Vertical or Horizontal Dispersion
What was the problem? Well, each of the three shooters had a different way of holding the gun and adjusting the rear bag. Shooter #1, the gun’s owner, used a wrap-around hold with hand and cheek pressure, and he was squeezing the bag. All that contact was moving the shot up, down, left and right. The wrap-around hold produced erratic results.
Shooter #2 was using no cheek pressure, and very slight thumb pressure behind the tang, but he was experimenting with different amounts of bag “squeeze”. His hold eliminated the side push, but variances in squeeze technique and down pressure caused the vertical string. When he kept things constant, the gun put successive shots through the same hole.
Shooter #3 was using heavy cheek pressure. This settled the gun down vertically, but it also side-loaded the rifle. The result was almost no vertical, but this shooting style produced too much horizontal.
A “Second Opinion” Is Always Useful
Conclusion? Before you spend all day fiddling with a load, you might want to adjust your shooting style and see if that affects the group size and shape on the target. Additionally, it is nearly always useful to have another experienced shooter try your rifle. In our test session, each time we changed “drivers”, the way the shots grouped on the target changed significantly. We went from a big round group, to vertical string, to horizontal string.
Interestingly, all three shooters were able to diagnose problems in their shooting styles, and then refine their gun-handling. As a result, in a second session, we all shot that gun better, and the average group size dropped from 0.5-0.6 inches into the threes — with NO changes to the load.
That’s right, we cut group size in half, and we didn’t alter the load one bit. Switching shooters demonstrated that the load was good and the gun was good. The skill of the trigger-puller(s) proved to be the limiting factor in terms of group size.
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Estimating Actual Cost per Round by Caliber
This article comes from the USAMU, which provide shooting and reloading tips on its Facebook Page. This week’s USAMU TECH TIP outlines a ballpark-estimate method of calculating the actual cost per round of different calibers. Some applications, and some shooters, by virtue of their high level of competition, require the very best ballistic performance available — “Darn the cost, full speed ahead!
If you are in serious contention to win a major competition, then losing even a single point to inferior ballistic performance could cost you a national title or record. However, this “horsepower” does come at a cost! Some calibers are barrel-burners, and some offer much longer barrel life. Look at this comparison chart:
Estimated Cost Per Round by Cartridge Type
Below are some estimated total expense per round (practice and competition) based on component costs, type used, expected barrel life and a standard, chambered barrel cost of $520.00 across calibers.
5.56x45mm: $0.46/round (barrel life 6,000 rounds)*
6mmBR: $0.81/round (barrel life 2800 rounds)
6XC: $0.97/round (barrel life 2200 rounds)
.308 Win: $0.80/round (barrel life 4500 rounds)
6.5-284: $1.24/round (barrel life 1100 rounds)
*Note the high round count estimate for 5.56x45mm. This is a bit deceptive, as it assumes a period of “lesser accuracy” use. The USAMU says: “Much of the difference you see here between 5.56 and .308 is due to using the 5.56 barrel for 100-200 yard training with less-expensive, 55gr Varmint bullets after its long-range utility is spent”.
Moreover, while some applications require specialized, high-cost components, others do not. And, if the shooter is still relatively new to the sport and hasn’t refined his skill to within the top few percentile of marksmen, a more economical caliber choice can help stretch a limited budget. Translation: More skill per dollar!
In this post, the prices for all items mentioned here were taken from a major component supplier’s current advertisements, and all brass was of top quality, except in the case of 5.56mm. There, 200 top-quality, imported cases were reserved for 600-yard shooting, and the other brass used was once-fired Lake City surplus.
Cartridge cases were assumed to be loaded 10 times each. [Your mileage may vary…] Bullet prices assumed the use of less-expensive, but good-quality match bullets for the bulk of shooting as appropriate.
The cost of top-tier, highly-expensive match bullets was also calculated for a realistic percentage of the shots fired, based on ones’ application. Barrel life by caliber was taken from likely estimates based on experience and good barrel maintenance.
Brass Costs Based on 10 Loads Per Case
Often, handloaders may calculate ammunition cost per round by adding the individual costs of primers, powder charges and projectiles. Many don’t consider the cost of brass, as it is reloaded several times. Here, we’ll consider the cost of enough top-quality brass to wear out a barrel in our given caliber, at 10 loads per case, except as noted above.
Don’t Forget Amortized Barrel Costs
Few shooters factor in the full, true cost of barrel life. Depending on caliber, that can dramatically increase the cost per round. For example, consider a long-range rifle in 6.5/284 caliber. This cartridge performs amazingly well, but at a cost. Ballpark estimated barrel life [in a top-quality barrel] is 1100 rounds. Some wear out faster, some last longer, but this gives a rough idea of what to expect.
Accurate barrels are a joy to use, but they are an expendable resource!
A top-quality barrel plus installation was estimated at about $520.00. At 1100 rounds, barrel life adds $0.47 per round to our total cost. Thus, what had started out as an [components-only estimate, with brass cost] of $0.76/round now totals $1.24 per shot!
Cost Considerations When Choosing a Catridge Type
Some shooters might ask themselves if they could meet their present needs with a more economical caliber. If so, that equates to more practice and matches per available dollar, and more potential skill increase on the available budget.
Each shooter knows his skill level, practice needs, and shooting discipline’s requirements. Some might shoot NRA Service Rifle or Match Rifle using a 5.56mm with a long barrel life. Others might be Match Rifle shooters faced with choosing between, say, a 6mm BR vs. 6XC. A realistic assessment of ones needs, performance-wise, may help guide the shooter toward a caliber that’s most optimized to their needs at the moment.
Admittedly, the factors affecting cost for any individuals circumstances can vary significantly. However, hopefully this will provide one useful method of evaluating one’s training and competition choices, based on their skill, goals and needs.
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Butch Lambert of ShadeTree Engineering provided this tip. Butch notes that many 6 PPC benchrest group shooters also enjoy shooting in score matches. But to be really competitive in the BR for score game, that means shooting a 30BR, which has a wider, .308-class rim (0.4728″ diameter). Likewise, if you want to compete in 600-yard registered BR events or in varmint matches, you probably want to run a bigger case, such as the 6BR, 6mm Dasher, or 6-6.5×47. Those cartridges also have the larger 0.4728″ rims.
To convert a PPC-boltface action to shoot the bigger cases you can spend a ton of money and buy a new bolt. That can cost hundreds of dollars. The simpler solution is to turn down the diameter of the larger cases on a lathe. Butch explains: “We’ve seen plenty of interest in rebating case rims. This lets you shoot a 30BR in score matches using your PPC action. All you need is a new barrel. This saves buying another bolt, receiver, or rifle if you have a PPC boltface. Anyone who has access to a lathe can do this job pretty easily. Yesterday I turned 150 case in about an hour.” Below are photos of a rebated 6BR case, along with the lathe form tool Butch uses to rebate the case rims.
Cutting Head for Rebating Rims
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DJ’s Brass Service now offers custom case hydro-forming to your exact specs. Darrell Jones offers this service for a variety of popular cartridges: 6mm Dasher, 6mm BRX, 6mm BRDX, and 6mm Shehane. After hydro-forming your brass, Darrell can also neck-up or neck-down the cases to meet your needs. For example, if you shoot a 22 Dasher, Darrell can hydro-form the cases and then neck them down to .22 caliber. He can also turn the necks to your specs (for an additional charge).
Darrell is a hydro-forming wizard who has perfected the process over the last couple of years. He has learned a few special techniques along the way to ensure uniform case-forming. Without revealing any trade secrets, we can say the Darrell has very special dies and Darrell doesn’t use a mallet or hammer — he has a system that is much more consistent. Darrell tells us: “Many of my customers take this brass and load it ‘as is’ and go straight to a match and shoot some very nice groups.”
Hydro-forming by Darrell costs $0.60 (sixty cents) per case with a minimum order of $60. Neck-turning is an additional $0.50 (fifty cents) per case plus actual return shipping. The turnaround is usually less than five days.
With Darrell’s hydro-forming service you don’t have to buy any special dies or other equipment. Darrell says: “Simply send me the brass you need or have it dropped-shipped to me along with a fired case that has not been sized. If you need formed brass for a new build (gun not yet fired), let me know and I will size the brass to fit within .001 of a PT&G GO gauge.”
For more information, visit DJsBrass.com, or call Darrell at (205) 461-4680. IMPORTANT: Contact Darrell for shipping instructions BEFORE sending brass for processing. In a hurry, don’t have time? Just call Darrell and he’ll make something work for you.
Hydro-Forming Customer Reports
Here are testimonials from recent customers.
“Recently had Darrell Jones of DJ’s Brass Service hydro-form 6 BRX brass for me. The turn around time was very fast and the brass was to the exact specification I ask for. I actually shot the hydro-formed brass in a match [without further fire-forming]. It shot a 3.597″ — pretty amazing. Let DJ do the work for you!” — Mike Wilson (3 Time IBS Record Holder; 2013 and 2014 1000-yard IBS Shooter of the Year.)
“Darrell Jones of DJ’s Brass Service went far beyond the call of duty, to assist me in preparation to shoot for my first time in an IBS match. I have had an interest in 1000-yard competition for many years and finally got the opportunity to try it. After researching the winning competitors, rifles, and rounds I ordered a Panda action with Krieger barrel in 6mm Dasher from Kelby’s. It was one week before the match and I had a rifle and no rounds. I contacted Darrell to hydraulically form 6mm dasher from Lapua 6mm BR brass. He formed the brass and had it in the mail the next day[.] Since I have only reloaded for hunting or magazine fed rifles I was not familiar with proper seating to allow land engagement of the bullets for 1000-yard accuracy. Darrell took the time to advised me every step of the way to allow me to shoot a 3.158″ (5) shot group to win my first round of my first competitive match ever.” — Mike Youngblood
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