|
|
October 23rd, 2012
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, 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.
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).
Results Are Barrel-Specific, Not Brand-Specific
These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.
Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.
Factory Ammo Provides a Benchmark
 If you have a .223 Rem, 6BR, .243 Win, 6.5×47 Lapua, 6.5×55, .308 Win, 30-06, or 300 WM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. When you complete a new 6BR rifle, it’s wise to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.
Share the post "Tech Tip: Same Load Varies in Velocity with Different Barrels"
October 15th, 2012
One of our readers has been shooting his 6BR with considerable success in tactical/practical matches. Thus far he’s been using Lapua factory-loaded 105gr ammo. The factory ammo has delivered superb accuracy for him — under 1/4 MOA at 100 yards. Now, he is making the jump into reloading. He asked for some tips on working up a good load for an 8-twist 6BR with a no-turn neck, and selecting reloading tools. Since other readers may be 6BR novices as well, here are some helpful hints…
Accurate Reloading Tips for the 6mmBR Cartridge
 ▪ Brass Prep — You need to look at the flash-holes to make sure they’re not occluded. A few lots of Lapua brass came with a little sliver/flake of brass in the hole, sort of like a quarter moon. You can clean that up with an inexpensive pin vise. Otherwise, there is no need to ream flash holes or uniform primer pockets.
▪ Neck Chamfering — You want to develop a good feel for neck chamfering. You don’t want/need to remove a lot of brass — just knock off the sharp edge. I use a Forster 45 deg “rocket” tool. It works fine. After a couple light turns, spin backwards to smooth the cut and then finish with a twist with a green scotch pad. If you use a deep-angle chamferer, be very careful not to overcut and remove too much brass.
▪ Neck Tension — On brand new, unfired Lapua 6BR brass, neck tension is excessive. You should run an expander mandrel down the case necks before the first firing. This will reduce the neck tension while it fixes necks that may be dented or out of round. After the first firing, we suggest sizing the necks so that, after they come out of your sizing die, the neck outside diameter (OD) is .002″ less than the neck diameter of a loaded round with bullet seated. If that doesn’t work, try the next size up bushing for .001″ tension. Many top shooters like low neck tension, but we’ve also seen heavy tension work. The .002″ under loaded OD is a good starting point with the 6BR. (But note — if you have thin-walled turned necks, you may need to use a smaller bushing, running your sized necks .003 or .0035 under the OD of a loaded round.)
▪ Primers — A lot of guys like the CCI 450 primers. They’re a lot cheaper than the Federal and CCI BR primers and may give a little more velocity. The cups are also hard, which lets you run faster loads with less concern about cratering. Wolf/Tula primers also have hard cups, but you must make sure to seat them deep enough.
▪ Load Development and Bullet Choice — With the 6BR and 100-108gr bullets, load development should be relatively easy. With Varget, Reloder 15, Norma 203B, or VV N150, between 30.0 and 30.7 grains should work as your final load. My match load is 30.3 Varget and that has shot under 2.0″ at 600 yards. Start at 29.0 grains and and work up in 0.2 grain increments, checking for pressure. DO weigh every load… twice. If possible, use a chronograph during your load work-up. 2880-2920 fps is a nice “sweet spot” for the 6BR, but slower can be very accurate too. (With custom actions, tight chambers, and long barrels, some guys are going even faster — but that’s hard on brass.)
If you have a barrel on the slow side, consider shooting the Berger 100gr ‘Match Target’ BTs. These bullets are very accurate, and we’ve found that you can drive them 75-100 fps faster than the Berger 108s or Sierra 107s at similar pressure levels. With the 100-grainers, you may find that you can hit a superior velocity/accuracy node, so they may shoot better overall than the 105-108 class bullets. Varget, RL15, and IMR 8208 all work great with this 100gr bullet.
For shooting from 300-500 yards, you should consider the lighter-weight bullets: Sierra 95gr MK, Lapua 90gr Scenar, Berger 95gr and 87gr VLD. The Sierra and Lapua bullets are very accurate and not sensitive to seating depth. In addition to the powders mentioned above, H4895 and IMR 8208 XBR work very well with the 90-grain-class bullets. One note about the smaller Berger VLDs — the Berger 95gr VLD and 87gr VLD both have very short bearing surfaces, so they work best in a chamber with a short-to-moderate Freebore. We had the best luck with the 95gr VLD about .010″ into the lands. We could achieve that with an 0.075″ Freebore chamber. But you won’t be able to hit the rifling with the 95s in a long-throated chamber. With this bullet we recommend sorting bullets by base to ogive.
 For guys with 10-twist barrels, try out the new Berger 87gr VLD. It was expressly designed to work great in the 1:10″ twist barrels. Forum member Mark Schronce reports that this bullet is extremely accurate and can be driven fast. It has an 0.412 G1 BC. Note: The new 87gr VLD, product #24524, is hard to find on the Berger website, but it IS available. Berger calls it a “hunting bullet”, but it works great on paper also. MidwayUSA has the 87-grainers in stock as item #77854.
▪ Pure Accuracy — If you are looking for bughole accuracy out of your 6BR, try the Berger 80gr FBHP ‘Match Varmint’ bullets (item #24321). Many folks have reported these bullets will shoot in the ones and low twos, even in 8-twist barrels. For 100- to 200-yard distances, these bullets are hard to beat for pure accuracy. Beyond those distances, you’ll want something with a higher BC. We’ve had good luck with the Berger 80s pushed by Vihtavuori N135, and IMR 8208 XBR.
▪ C.O.A.L. — Bullet seating depth is very important. You should get the Hornady (Stoney Point) O.A.L. Gauge (shown below). This will let you discern the OAL at which the bullets just contact the rifling. The trick is tapping gently on the stick. (Get a wood dowel as the bullet can get stuck if you tap a little too aggressively.) With some practice, measuring is quick and you can get repeatable measurements of your distance to lands within .001-.002″.
A good starting point for the Berger and Lapua 105s is about .010-.015 IN the lands and then work back. Each barrel is different, but about .010″ in the lands works for many folks. One guy I know started at .012″ in the lands with Berger 105s, adjusted his load up from 30.0 to 30.4 Varget, and within an hour he was done with load dev — the gun was shooting in the low 2s. He went out and won his first match with that load the next day! With the Sierra 107s you might want to start .020″ out of the lands.
▪ Seating Die — We recommend the Wilson Micrometer Seating Die. The adjustable top makes it really easy to play with seating depths. Keep in mind, however, that moving 5 hash marks on the die may not give you exactly .005″ seating depth change — it will be close, but you should measure and write down the actual base to ogive length. FYI, I measure base to ogive of every loaded round. Occasionally you’ll find a bullet that ends up seated a little long or short.
NOTE: The fit of the 6BR Wilson seating die is very tight. You may have difficulty getting a fired case into the die if you do not full-length size the case first. Even with FL-sized cases, there may be a vacuum fit that makes the loaded round a little hard to remove. If you can’t easily extract your loaded round, try lifting the entire micrometer head and attached stem. This can release the vacuum so the case can slide out easily (unless there is a really tight fit). If that doesn’t work, here’s another trick — use the end of a Popsicle stick placed under the cartridge rim to lever the case out. I’ve found that the “working” end of a metal spoon works well too, but be careful not to nick the bottom of the die.
Share the post "Quick Tips for Reloading the 6mmBR Cartridge"
June 14th, 2012
Last month, shooting at the Piedmont Gun Club, Chad Jenkins put together a stunning 1.495″ Aggregate at 600 yards. Once certified, that will be a new IBS 4-target Light Gun record. Chad’s smallest group was a 1.033″. Chad’s 1.495″ Agg breaks the existing 1.6068″ record set by Sam Hall in 2011. Chad was shooting a no-turn-neck 6mmBR featuring a BAT action, Krieger barrel, and Shehane ST-1000 fiberglass stock. We had the chance to talk with Chad and learn more about his record-setting rifle, and the methods he uses to achieve superior accuracy. Chad was kind enough to tell us about his equipment and what he does to build very, very accurate ammo. For starters, Chad wanted to “say thanks to Lewis Winkler, James Coffey, Mike Davis, and Larry Isenhour” all of whom provided invaluable help and support over the years.
The Record-Setting Rig
Chad credits much of his success to an “fantastic Krieger barrel that shot great right out of the gate”. It’s a 1:8″ twist, HV contour, finished at 28″ — nothing unusual there. Mike Davis did the chambering, barrel-fitting, and barrel crowning. One reason the gun shoots so well is that Chad’s friend James Coffey did the stock work and bedding, and also added weight to the Shehane ST-1000. Chad says “James really knows what he’s doing”. For optics, Chad uses a Leupold 45X competition scope, with fine cross-hair (FCH). Chad says he can “aim at the ‘X’ at 600 yards more precisely with the cross-hairs than with a target dot.”
$200 Front Rest Good Enough to Set Record
You may be surprised that Chad set his record with an inexpensive Caldwell Fire Control Joystick rest, that sells for about $203.00 on Amazon.com. The Caldwell isn’t fancy, but it did the job. Chad says: “I have a family and a young boy. I don’t have the money to pour into equipment like some other people. I will continue to use my Caldwell, but I have recently modified the base. The record though was set with an unmodified unit, just as it appears in the photo.”
Chad Shoots a “Classic” 6BR Load, But He Jumps his Berger VLDs
Chad gets great accuracy with a pretty “standard” 6mmBR match load: 30.5 grains Varget, CCI 450 primers, Berger 105gr VLDs, in Lapua “Blue Box” brass. (Editor’s Note: That load can be too hot in some guns in summer conditions). Chad loads his ammo with a Redding bushing full-length sizing die with an 0.266″ bushing. Chad says: “That’s a good size for the ‘Blue Box’ Lapua brass (I tried a 0.268″ and I could pull the bullets out with my fingers). I seat my bullets about 0.020″ OFF the lands with a Redding Comp seater die.” The brass that shot the record Agg had about 10-11 firings on it, and Chad has NOT annealed the cases yet. While Chad is a very exacting reloader, he believes in the KISS principle — he doesn’t ream flash holes or uniform primer pockets. While he weighs every load with an RCBS Chargemaster, he normally does not double-check charges with a second balance. Chad tells us: “I just get the Chargemaster to where where it is going consistently and run with it.”
Knowing that gun-handling and barrel maintenance are key elements of accuracy, we asked Chad about his shooting style, rest set-up, and his cleaning regimen:
Shooting style: “I try not to touch the gun, except with my thumb on the back of the triggerguard, and my index finger on the trigger. I use just a slight amount of pressure as the finger pulls the trigger. I don’t have any pressure on my shoulder. The buttplate is just barely touching my shirt.”
Rest position: “I usually let the gun run out to the stop. But there’s not much overhang. It hangs over an inch and a half. That’s where I always shot it. In the rear the ears are pretty much centered on the underside of the buttstock.”
Cleaning: “I use Montana X-Treme with patches and bronze brushes, and I clean every 35-45 rounds. I don’t brush a lot — I kind of go on feel, anywhere from 4-10 strokes. The gun shoots so incredibly well, I want to baby it, so I try not to over-clean.”
View Chad Jenkins’ Four (4) Targets
Common Sense Tips for New Shooters
Chad offered some advice for shooters starting out in the 600-Yard Benchrest game:
Reloading — I don’t claim to be an expert. But I will say that consistency is all-important. I learned this first from my friend Lewis Winkler (who passed away), and then James Coffey. Lewis always told me that the main thing is that you must be consistent in everything — when you’re sizing, when you’re weighing, when you’re seating bullets. You can’t be deviating and expect your loads to shoot.
Mental Game — I don’t go to a match to beat anybody, or to compete against anyone in particular. I shoot the best I can shoot and let the chips fall where they may. Even in practice, I basically compete against myself and I try to do the same thing in a match.
Focus (when to have it and when to relax) — I do try to stay focused when I’m shooting. But I also try to get away from the pressure between relays. A lot of the guys spend 15-20 minutes looking at everybody’s targets. I just look at my own targets and go back and sit down and relax. I don’t try to overthink things. When I was a teenager I was a successful competitive golfer. And in those days, I didn’t think about it … I just stepped up to the ball and hit it. I think, with some competitive activities, “thinking too much” can probably mess you up more than it helps.
Share the post "Profiles in Accuracy: Jenkins Sets 600-Yard Agg Record with 6BR"
May 13th, 2012
 The regular, monthly 600-yard benchrest match at the Piedmont Gun Club in Rutherfordton, NC rivals a National event in terms of the quality of the shooters and the rifles. And just yesterday, a pending new IBS 600-yard, four-target Light Gun Group Aggregate Record was shot. Chad Jenkins put together a stunning 1.495″ Aggregate shooting a Light Gun with Shehane Tracker stock and Krieger barrel. Chad’s smallest group was a 1.033″. The caliber was a ‘Plain Jane’ 6mmBR. Chad’s 1.495″ Agg breaks the existing 1.6068″ record set by Sam Hall in 2011.
Sam Hall reports: “Congratulations goes out to Chad Jenkins today at Piedmont Gun Range, Rutherfordton, NC. Chad shot a 1.495″ four-target aggregate in LG this morning! The old record (1.6068″) was shot by yours truly last July. That is some kind of great shooting! Chad has been shooting great and kicking our tails for two years now. You will probabbly be hearing more from him. What I know is: he was shooting 105gr Berger VLDs (with Varget and CCI Primers) in a standard 6BR, with BAT action, ST-1000 stock, and 1:8″-twist Krieger barrel. I think it is safe to say it is a ‘hummer’!”
Share the post "Chad Jenkins Sets IBS 600-Yard LG Record with 1.495″ Aggregate"
August 28th, 2010
 What kind of accuracy do you think a tubegun can deliver with factory ammo — during barrel break-in? Perhaps 0.6″ at 100 yards, half-MOA if the conditions are perfect? Well you may want to change your preconceptions about tubeguns — and factory ammo. This Eliseo R5 repeater, smithed by John Pierce with a Pierce CM action and Broughton 5C barrel, shot the Lapua 90gr factory ammo into flat ONEs during the break-in session. A day later, in tricky 8-14 mph winds, the gun nailed a witnessed and computer-measured 0.174″ 5-shot group using the 105gr factory ammo. That would be impressive for a “full-race” benchgun with precision handloads. For an across-the-course rifle shooting factory ammo, it’s pretty amazing.
Eliseo Tubegun Shoots in the Ones
This accurate rifle belongs to our friend (and designated expert trigger-puller) Joe Friedrich. During the initial break-in session, since his reloading dies had not yet arrived, Joe decided to start with some Lapua factory-loaded 6BR ammo he had on hand. After doing a few two-shot-and-clean cycles (with patches and nylon brush), Joe decided to try a 3-round group just to see if the Broughton barrel had some potential. To his astonishment, the Eliseo R5 put three rounds in 0.100″ (photo below left). Joe then cleaned the barrel again, shot a couple foulers and tried a 4-shot group. The results were just as stunning — 4 shots in a mere 0.104″ but three in virtually one hole (photo below right).
 
 |
Joe’s Halloween 6BR Tubegun SPECS
Chassis: Eliseo R5 Repeater, fitted with Eliseo Front Sled and Rear Bag-Rider.
Gunsmithing: Pierce Engineering Ltd..
Chambering: 6mmBR Norma, .272″ No-turn Neck, approx. 0.090″ freebore.
Action: Pierce Engineering, Rem 700 footprint, Chrome-Moly, fluted bolt.
Barrel: Broughton 5C (Canted Land), 27.5″, 1:8″ twist, Medium Palma contour.
Trigger: CG X-Treme Two-Stage.
Optics: March (Kelbly’s) 10-60x52mm.
Ammunition: Lapua 6mmbr 90gr Scenar BT (#4316045, non-moly), 105gr Scenar BT (#4316046, non-moly ). |
 You Can’t Believe How This Gun Shoots
Joe called your Editor and said “You can’t believe how this gun shoots with factory ammo!”. So we arranged a photo session for the next afternoon, where I could verify the rifle’s accuracy. Well it turned out the conditions were way more challenging than when Joe broke in the barrel the day before. Winds were running 8-14 mph and were swinging through 180 degrees half-way down the range. Joe fired a few 90s through the Oehler chronograph at my request, then opened a box of Lapua 105gr factory ammo. It took about four rounds for the barrel to settle in after being cleaned the night before. Then Joe got serious, and with your Editor looking over his shoulder, he drilled a 0.174″ five-shot group in switching winds, doping every shot. Joe felt the gun could have shot tighter but he missed one wind call.
Serious Accuracy with a Multi-Purpose Rifle
So there you have it — a tubegun that shoots in the ones with factory ammo. Joe says that, at least with the 90s, the Elesio R5 shoots as well as his 6 PPC. Joe stressed that “steering the tubegun is hard work. You really have to concentrate compared to a purpose-built bench gun like my PPC. With the tubegun, everything has to be perfect on every shot — hand position, cheek position, stock position in the bag. If you’re off just a little bit, it’s easy to steer the gun the wrong way and send a shot out of the group.”
Accuracy Great but Fouling Heavy and ES Could Be Better
Have there been any negatives to Joe’s 6BR tubegun experiment so far? Well, the Broughton 5C barrel, while phenomenally accurate, shows signs of being a bad fouler. Copper built up pretty quickly over the first 25 rounds or so. We saw best accuracy with a recently-cleaned barrel. Hopefully the fouling will lessen as the barrel polishes in with use. And the canted land barrel is slower than average with the factory ammo. Lapua rates its 90gr naked-bullet ammo at 2950 fps with a 26″ tube. In Joe’s 27.5″ barrel we only averaged 2901 fps. With the 105gr factory ammo, which is rated at 2790 fps, we averaged just 2694 fps. That’s quite disappointing. Also the ES on the factory ammo, slightly over 50 fps for both bullet types, wasn’t particularly good. Still, the overall results were stunning. This gun shoots better than many long-range benchrest rifles running carefully-developed handloads — and it does that with factory ammo, right out of the box.
Share the post "Eliseo R5 Tubegun Shoots in the Ones with Factory 6BR Ammo"
August 1st, 2010
 Many readers have asked, “Is there an ammo case that holds short BR, PPC and Grendel cases securely — one without a lot of extra clearance that allows fired brass to fall out of their slots if the box is tipped?” Yes, the J & J BR-100 Ammo Case fits BR, PPC, and Grendel cases just right. Many folks use the large green/red MTM 100-round ammo boxes for transporting 6BR and 6PPC ammo. The big MTM boxes work fine with loaded rounds, but not so great with fired cases. If you tip the MTM box on its side, the empties can spill out. That’s frustrating if you’ve meticulously sorted your cases. You won’t have this problem with the J & J 100-round BR-100 ammo case. It has tighter vertical clearance, so your empties won’t come out of their slots if the case tips over or is stacked upside down.
BR-100 cases are bargain-priced at just $4.88, and they come in Red, Blue, Smoke, or White colors. In addition to the BR-100 case, varminters who need to carry large numbers of loaded rounds should check out J & J’s 175-round Rifle Ammo Case (photo below). This foam-lined ammo transporter, item LR-175, costs $18.16 and is the largest-capacity ammo case we’ve found. For more info go to JandJProducts.Com.
Share the post "BR/PPC Ammo Carriers Hold Cartridges Securely"
April 5th, 2010
The 30th Annual Hickory Groundhog and Egg Shoot was held on April 3rd, 2010. Saturday’s competition proved a great day for the Brady family. Our friend (and Forum member) Terry Brady won the Custom Rifle division with a 99 score, setting a new record. Terry edged his son Chris, who shot a 98, matching the previous Custom Class record set by fellow North Carolinian Sam Hall. (That will teach Sam to go fishin’ on shoot day!) The threesome of Terry Brady, Chris Brady, and Greg Cooper also won the Hickory Team competition. Conditions were excellent for Saturday’s match, with calm winds. A total of 167 shooters attended the Hickory Shoot, which offered over $4000.00 in cash, coupons, and hardware.
Bill Shehane of D&B Supply was on hand for the match. Bill reports: “Chris Brady tied Samuel Hall’s all-time record of 98 points today only to have his father Terry Brady take it away with a scorching 99. Congratulations to this fine Father-Son team for a 1-2 finish in this year’s shoot. That’s a lot of loot for the Brady boys. Couldn’t happen to two better guys and I for one know just how much work it takes to finish 1st and 2nd. Terry told me when he arrived on Saturday morning that he intended to take home a Tracker stock. My Granddad always said if ya can do it — ‘It Ain’t Bragging!'” Actually, Terry didn’t get it quite right. His son Chris won the Tracker while Terry earned $300.00 plus a 50% off coupon for a Nightforce scope. Either way… it’s all in the family.
Terry Brady Busts Record with Heavy 6BR in Custom Class
Terry and Chris Brady brought two guns to the match, both chambered as 6BRs. The first was a special 38-pounder built by Mike Davis. It featured a BAT DS action, weighted Shehane Tracker stock, Krieger gain-twist barrel and Nightforce 12-42x56mm BR scope. The second gun was a 17-pounder built by Glenn Williams with a Borden action, Shehane tracker stock, Krieger 8.5-twist barrel and Nightforce 12x42x56mm BR scope.
Terry reports: “The conditions were almost perfect for shooting. Very small guests of wind with no mirage. I set the new score record with 99. Chris and Josh Duckworth tied the former record set by Sam Hall of 98. Josh was shooting a Borden 6BR as well. 17 people hit the egg at 500 yards, including myself, Chris, Chris’ girlfriend Jessica, and Josh. Chris, Jessica, Ben Yarborough and I busted 4 eggs in a row with the 38-pound rifle before Larry Willis (the Match Director) jokingly asked us to move on and leave some fun for the other guys.”
Share the post "Bradys Assault Records and Win Custom Class at Hickory Shoot"
September 3rd, 2009
When developing a load for a new rifle, one can easily get consumed by all the potential variables — load 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. We were recently testing 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 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 had his own issues with the bag and rest and 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 was pretty much a horizontal line with almost no vertical. Hmmm… what gives?
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. Shooter #2 was using no cheek pressure, and very slight thumb pressure behind the tang, but he was experimenting with different bag positions. His hold eliminated the side push, but variances in bag position 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 fairly heavy cheek pressure. This settled the gun down vertically, but it also side-loaded the rifle. The result was almost no vertical, but a lot of horizontal.
A “Second Opinion” Is 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.
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.
Share the post "Load Development — Changing "Drivers" Reveals Human Factor in Gun Performance"
August 25th, 2009
Shooting at Williamsport, PA on August 15th, our own Jason Baney shot a remarkable 100-6X, 4.864″ ten-shot group at 1000 yards, breaking the previous 100-5X, 4.900″ Light Gun Score record set by Ed Kenzakoski in June. And yes, Jason was shooting the diminutive 6mmBR cartridge (no-turn neck) with pointed 105gr Berger bullets and a stout load of Alliant Reloder 15. Baney’s 6BR Broughton-barreled Light Gun (Stiller Diamondback action) was smithed by Mark King, who also built Ken Brucklacher’s record-breaking Heavy Gun.
 |
 |
Jason’s glory was short-lived however. The very next day, August 16th, Andy Murtagh shot a 100-4X, 4.2766″ group during match 5 of the Reade Range (Allemans, PA) 1K Benchrest League. Though Andy had only four Xs to Jason’s six Xs, Andy had the smaller group. By Williamsport rules, group size trumps X-count (even in score shooting) so Andy is the new Light Gun 1000-yard Score record-holder. Andy’s record-setting 6.5-284, smithed by Sid Goodling, has a Master 1000 stock and Bat action. Andy’s load was 47.5 grains of H4350 pushing 142gr tipped Sierra MKs in Winchester brass.
Congrats to both Andy and Jason for some great shooting last weekend! It’s impressive to see such small, ten-shot groups all centered up. Hey Jason — OK, we’re convinced. That round-robin Ladder Testing Procedure must really work.
Share the post "1K Score Record Broken Twice in PA Matches"
July 9th, 2009
 Large quantities of Lapua brass, for most of the popular cartridge types, have recently arrived at many vendors including Bruno Shooters Supply, Graf & Sons, and MidwayUSA.
Bruno’s has almost all types of Lapua brass in stock and here are some sample prices: 6mmBR brass for $63.00/100; .308 Win for $55.00/100; 220 Russian for $74.00/100; 6.5×47 for $85.00/100. Note — if you’re thinking about building a tactical rifle, the 6.5×55 brass is just $55 per hundred (same price as .308 Win, but much cheaper than 6.5×47).
Bruno’s also has received large supplies of Berger 6mm 105gr VLD bullets. These have been out of stock for several months. Call (623) 587-7641 for pricing.
Grafs.com has Lapua 6mmBR brass for $69.59/100, 220 Russian for $79.99/100, and 6.5×47 brass for $91.99/100, but those prices include shipping. Grafs has most other varieties of Lapua brass in stock, including 222 Rem, 223 Rem, 243 Win, 6.5×55, 6.5-284, .308 Win, and 338 Lapua Mag.
Share the post "Lapua Brass Arrives at Vendors. Berger 105 VLDs at Bruno's."
May 6th, 2009
 Roger Amos (aka Expiper) is a long-time friend of this website and member of our Shooters’ Forum. We were pleased to see that, while competing at the NBRSA 600-yard Nationals, Roger set a new NBRSA Light Gun 3-target score record of 145-4X. Roger set the record with his 13.4-lb Panda-actioned, 8-twist 6BR, the same gun he shoots in 100/200 yard benchrest matches. Roger has demonstrated that a single gun can be competitive at multiple distances. This concept of a “universal benchrest rifle” is something we’ve advocated for quite some time, as we would like to see more 600-yard shooters compete at 100/200 and vice-versa. Also, with the tough economic times, it makes good sense to have one rifle that can do double-duty. Roger explains that his record-setting rifle “is typical of what I [now shoot] because of the high cost of building a target gun that is only legal/shootable at one distance or discipline. I am disabled and can’t carry a heavy gun because of my back. Out of necessity came up with this ‘universal rifle’ solution.”
Roger’s record-setting 6BR features a 28.5″ Krieger barrel (UHV profile), with a .237″ bore, .271″ no-turn neck, and .040″ freebore. That freebore length is much shorter than on most 600-yard guns, which typically have .090″-.120″ freebore. With an .040″ freebore, Roger can shoot both the 100+ grain bullets as well as the 62-68 grainers. At 600 yards, Roger runs Berger 105gr VLDs, .015″ into the lands, pushed by Reloder 15 and Fed 205M primers.
Fast-Twist Barrels at Short Ranges
Roger tells us that: “I have been shooting 8-twist barrels for several years now at 100-200-300 and they will shoot just as well as a traditional 14-twist (point blank) barrel … IF you use GOOD bullets. I have found that Barts and Fowler 62-68s will stand the extreme rotation associated with 3600+ fps and 1:8″ twist. Some bullets can’t take it. You just gotta try whatever you have and see for yourself. I have found the most accuracy at 100-200 with the 66-80 grain Fowler bullets or the 80gr Bergers. At 300 yards the 80gr Berger or 90gr Berger BT are excellent! At 600-1000 yards, the Berger 95gr VLDs can outperform the 105s because of their extra speed (although the 95s have a lower BC, their greater velocity can offset the BC advantage of the heavier bullet.)
Most of my stocks are around 22 ounces and give a finished weight of approximately 12 pounds. My Kelbly Klub stock on this gun is 48 ounces, for an all-up weight of 13.4 pounds. To help with balance, this particular stock has extra matrix in the fiber and is heavier than normal for point-blank guns. This gun can make weight as a Heavy Varmint but not as a Sporter — even if I used a 5-lb barrel.”
Pre-loading vs. Loading at the Match
Roger often loads at the range, but this wasn’t feasible at the NBRSA 600-yard Nationals. Roger explains: “When shooting ‘point blank’ (100/200) events, I usually load at the match like the majority of shooters. However this 600-yard event in Sacramento required airplane travel. These days, when flying, you are very limited as to cargo weight. Also you can NOT carry gun powder or primers. In your checked luggage, you are limited to 5 kilos (11 lbs.) of LOADED ammo and two long guns (or 5 pistols). Accordingly, I couldn’t take my dies/press/etc. with me, so I preloaded for the 600-yard Nationals.”
Share the post "Amos Sets 600-Yard Record with 'Universal' Benchrest Rifle"
April 19th, 2009
BR Armament Technologies (B.R.A.T.) of Saluda, VA is currently producing AR uppers chambered for the 6BR and 6BRX cartridges. Unlike some other previous AR conversions for the 6BR cartridge, the BR15 uppers produced by B.R.A.T. do not merely use a .223-sized bolt opened up to fit the .308-sized rim of the 6BR case. Instead B.R.A.T. employs a different bolt design that is bigger, and significantly stronger in the lug area. Shown below is a .223-sized bolt (left) and a BR15 bolt from B.R.A.T. on the right.
The B.R.A.T. BR15 upper receiver has been specifically designed to use the 6BR family of cartridges. It has a larger bolt, modified bolt carrier, modified upper receiver, larger barrel extension, and most importantly an all-new magazine designed specifically to handle the BR class of cartridges. All other parts are standard AR15. The folks at B.R.A.T. have developed their own magazines. These are 5-round center-feed dual column magazines that work with the 6BR, 6BR-derived cases (like 22 BR), and the 6BRX. Since the round feeds from the center, the mags can also be used for single-feeding.
B.R.A.T. is operated by two long-time competition shooters, both High Power High Masters, both Distinguished Riflemen, and both former captains of the U.S. Air Force Shooting team. President Eric Bellows has placed in the top 10 in the NTI and Presidents matches many times. Eric is former VT State Champion. Bill Walter, Chief Development Engineer, is former FL State Champion, Eliah Root team member, and is current military Palma Match record holder.
NOTE: We have not used or tested a B.R.A.T. upper or magazine. We are just passing on this information at the request of readers. You will find more product specs, and comparitive ballistics, on the B.R.A.T. website. Currently BRAT-15 uppers retail for $1390 with a Douglas barrel or $1550 with a Krieger barrel, chambered either as 6BR or as 6BRX. For another $100, B.R.A.T. offers uppers chambered in 22 BR, 6.5 BR, or 7mm BR. For more info, email 6BRrifles [at] bratrifles.com, or call (804) 824-7248.
B.R.A.T. 6BRX Upper Receiver with 28″ barrel and RPA Tall Boy sight
Share the post "B.R.A.T. Offers 6BR and 6BRX Uppers for AR High Power Shooters"
|
