Forum member Keith T. (aka “KT”) is in the U.S. Navy, so he has a fondness for seafaring, nautical color-schemes. Here is KT’s new F-Open rifle, smithed by Accurate Ordnance out of Winder, Georgia. The gun is chambered in .284 Winchester for Lapua brass (necked up) and 180gr Berger Hybrids.
KT admits, “It’s a little bit different than most in appearance!” But KT likes it that way: “When I had Accurate Ordnance build it, the only thing I specified was the stock, action, caliber and barrel length. I left the rest up to them. I think they did a pretty awesome job.”
The gun features a Pierce cone-bolt long action (with Jewell trigger) in a McMillan F-Class stock. The barrel is a Brux 31″, 1:9″ twist in the Brux “F-Class contour”. Sitting on top is the new Nightforce 15-55x52mm Competition scope with turrets and sun-shade coated blue to match the blue-coated action, bolt handle, rings, trigger guard and barrel.
The build came out great, but there were a few “bumps on the road”. KT explains: “This rifle took a long time to finish. When it comes to building guns I always joke and say if it weren’t for bad luck I wouldn’t have any luck at all. We started ordering parts in September 2012. Somehow I managed to order the stock from McMillan for the wrong Pierce action. After a bunch of scrambling and hard work on Accurate Ordnance’s part we were able to get my screw-up fixed. Then we ran into a few more snags. AO wanted to have the scope on hand before doing the coating. The first trigger was not up to standard with AO so they ordered another one and the list goes on. The rifle is finally done though and I couldn’t be happier.”
Editor: With Jerry Tierney steering a straight .284 Win to victory at the recent NBRSA 1000-Yard Nationals, we thought readers would appreciate a “second look” at this story. Our friend Bruce Duncan talks about the .284 Win and explains why it has proven so successful in long-range competition.
Building a Straight .284 Winchester
Sometime back–at least two years ago–Jerry Tierney confided in me that he was givng up on the 6.5s, and moving to the 7mms. “If you could only shoot one 7mm, Jerry,” I asked, “which would it be?” … “Straight 284 Win,” he answered.
So when I was thinking to rebarrel my 6.5×47 Lapua, in the fall of 2010, the .284 Win came immediately to mind. I am not about to argue the primacy of any chambering. I look at the dominance of the 6mm Dasher, at Missoula, say, or the recent NBRSA 600- and 1000-Yard Nationals and wonder.
And I’m reasonably convinced that none of us ever makes an entirely rational decision — one based purely on fact, and void of prejudice and emotion. But I knew a bunch of the U.S. F-Class guys were moving to 7mm, and decided to build one myself. This would be a NBRSA Heavy Gun, using my existing Barnard PC twin-port action, and my existing Shehane MBR Tracker stock. Going to the 7mm made sense to me — an accurate heavy bullet with a high BC, such as the Berger 7mm 180gr Hybrid, has a good chance of getting where one wants it to go. That’s particularly important when you’re shooting in tough wind conditions.
I ordered a 1:9″-twist barrel from Bartlein with 5R rifling and 1.250″ straight contour. (By the way, MT Guns has racks of Bartlein barrels if you need one right away.) I spoke at length with Ray Bowman of Precision Rifle & Tool (PR&T), who has immense experience with the .284 Win, and his fingerprints on a lot of winning rifles. Ray was supportive.
“The .284 Shehane isn’t enough bang for the buck”, Ray suggested. I sense he was telling me that I could achieve what I wanted with a standard .284 Win, without the cost of custom-run dies or the hassle of case-forming. I had David Kiff of Pacific Tool & Gauge cut me a reamer with a .313″ neck. I hadn’t decided on a bullet — I shoot Bergers exclusively — but watched the results from Phoenix in 2011, and noticed Bryan Litz did well with his .284 Win, shooting the Berger 180 Hybrid, as did Danny Biggs, shooting a 7mm RSAUM. I did some preliminary 100-yard load testing, and settled on a few loads I wanted to try (at longer range) with the Berger 180.
Shooting in good conditions on an Ojai, California morning, I tried three, five-shot groups with three different loads at 600 yards. One load in particular gave me two groups out of three at 1.8xx”. That’s pretty darn good at 600. The only surprise was that the bullets were seated to have the ogive just kiss the lands, rather than the slight jump that most were using.
It turned out that my load development wasn’t a fluke. The gun shot well, taking Third Place, 6-Target Aggregate Heavy Gun Group at the 2011 NBRSA 1000-Yard Nationals in Sacramento. Together with my 6×47 Lapua Light Gun, I took Third Place Overall. (The LG also featured a Barnard Action, Bartlein barrel, and Shehane stock.)
Great Accuracy Is Possible
So I was not surprised when Ed Docalavich, one of MT Guns clients, wrote to say how happy he was with the .284 Winchester we built for him. He attached one of the proverbial “Wallet Targets” from load testing. You can see it at right. There are five (5) shots at 100 yards, in a ragged hole you could practically cover with the Excedrin tablet in the photo. Not bad for a stout-recoiling rifle. Ed’s gun features a Barnard P action, Bartlein 5R 1:9″-twist, 1.250″-straight barrel, chambered for a no-turn neck.
Like I said, I’m not about to argue the primacy of any particular chambering, and my hat is off to the 6mms that do so well at 1000 yards. But I like the idea of a heavier bullet; the Berger 180gr Hybrid seems like magic. And as you might imagine, I don’t think it’s any coincidence at all that Ryan Pierce recently set a new 1000-Yard F-Open Record shooting the straight .284 Winchester. (READ Pierce Record Story).
Readers said they enjoyed our write-up of an innovative, offset-stocked Heavy Gun that set three multi-match Aggregate IBS records last year. If you’re a fan of “Heavy Artillery” here’s an impressive rifle from Forum member ‘Straightpipes’ that we spotlighted last year. If you missed it the first time — check out this engineering Tour De Force, complete with a custom-built, joy-stick REAR rest. We’re mightily impressed by the cutting-edge design and superb metal-work displayed by this “home-built special”. ‘Straightpipes’ certainly proved that American “know-how” and creativity is still alive….
Coaxial (joy-stick) rests allow both vertical and horizontal movement with a single control. If you want to make a diagonal shift in point of aim, you can do this with one, smooth, continuous movement. Until now, this advantage has been limited to front rests. Well there’s some new technology in the benchrest world. Forum member ‘Straightpipes’ has created a coaxial rear joystick rest. He built this simple, compact rear rest in his home workshop for use with his 40-lb Heavy Gun. In combination with a vertically adjustable front rest, this new rear joystick rest allows aiming to be controlled from the rear, with your left hand in a comfortable position.
Straightpipes Rear Coaxial Rest — Design and Features
The rear rest is crafted from aluminum with a stainless steel forward-pointing joystick. Total weight, including the long, stabilizing base foot, is about 10 pounds. Though the rear rest doesn’t seem to have a large movement range, the system offers plenty of “on-target” travel. At 100 yards, the rest offers 10 MOA left, 10 MOA right, 5 MOA up, and 5 MOA down adjustment. That’s plenty of range for most targets, once you center the Point of Aim vertically using the captain’s wheel on the front rest, which Straightpipes also crafted himself. Click Square Photos Below to see Large Images.
Inside the rear cradle sits a Protektor rear sandbag, with Cordura fabric filled with ordinary sand. This fits the 3″-wide bottom of Straightpipes’ 40-lb heavy gun. There are some sophisticated components you can’t see in the photos. The rear rest can pivot (right or left slightly) to stay aligned with the front rest (as adjusted to level the cant of the rifle). Straightpipes says: “With the pivot, whatever I do to the front, the rear follows.” The basket (cradle) also employs a 20-lb bias spring system to handle the weight of the Heavy Gun. This prevents the co-axial system from binding, so it is fluid and easy to operate. Even with 20 pounds of gun weight on the rear, the joystick can be easily manipulated with a light touch of thumb and fore-finger.
Video Shows Rear Coaxial Rest in Action
Watch the video below to see how the joystick controls the rear rest. Total joystick movement is about a 2.5″ sweep. This gives 20 MOA total windage adjustment at 100 yards, and about 10 MOA vertical.
About the Straightpipes Front Rest
The coaxial rear rest is designed to work with the massive front rest as a system, though they are NOT connected, so as to comply with IBS Heavy Gun rules. The 30-lb front rest supports exactly half the weight of the rifle and is used to set gross elevation. Windage and fine elevation is controlled in the rear. Straightpipes also designed and built his beefy front rest himself. As with his rear coaxial unit, the front rest pieces were all shaped by hand on a belt sander after being milled out. Straitpipes even “finish-sculpted some pieces with hand files the old craftsmen way.” The main center support column was milled with extremely fine threads. This allows the captain’s wheel to turn with little effort and no locking mechanism is required. Straightpipes does not need to fuss with locking knobs when he sets gross elevation. To help keep the unit from binding, there are stainless guide shafts on the left and right. These shafts slide in oil-impregnated bronze bushings.
40-lb Barrel Block Heavy Gun with Savage Action
Straightpipes built this beautiful set of rests to work with his 40-lb Heavy Gun. Chambered in 7mm WSM, the gun features a Savage Target Action, and a Brux 32″, 1.300″ straight-diameter barrel fitted with a custom barrel nut. The barrel is clamped forward of the action in a 9″-long barrel block. This allows the Savage action to free-float. The block, also built by Straightpipes, looks fairly standard, but it has some clever design features. Between the barrel and the block there is sleeve that is slightly compressed when the block’s bolts are tensioned. This sleeve, made of a proprietary material, eliminates metal to metal contact between barrel and block. Straightpipes believes this enhances accuracy and provides some damping. Other shooters with barrel-block guns have used epoxy between block and barrel, but that makes disassembly difficult. The sleeve system on Straightpipes’ gun allows the barreled action to be easily removed from the stock. In addition, the compressed sleeve system is very stable — Straightpipes doesn’t have to fiddle with the bolt torques on his block.
‘Black Beauty’ Stock Made from Resin-Soaked Laminated Wood, with Rust-Oleum Finish
Straightpipes built the beefy stock himself. It is made from “red oak” wood soaked in resin and then laminated together with JB Weld. The rear section features a polished aluminum buttplate and twin metal “runners” on the underside, where the stock rides the Protektor Cordura bag. Straightpipes says the stock is very stable: “it absolutely does not flex or warp with changes in temp or humidity”. We asked Straightpipes about the stock finish. To our surprise, “Pipes” revealed he used inexpensive Rust-Oleum fine texture outdoor furniture paint. “Pipes” told us: “I’ve been using this stuff for years. It’s abrasion proof and tough as nails — the bags won’t wear it off. It’s solvent-proof, won’t get soft or bubble up. It cleans up with a damp cloth, just rub it down and it looks like new.”
As designed and crafted by Straightpipes, this Heavy Gun rest system is impressive. The rear rest is brilliantly simple, and beautifully finished. But the important question is: “how does it shoot?”. Straightpipes reports that the whole system exceeds his expectations: “The rear rest actuation is smooth and positive. It works smoothly in conjunction with the front rest. Everything is working together — there’s nothing that’s fighting another element of the system. The gun tracks straight. When it returns to battery, the thing is pretty much waiting for you shot after shot.” The rear rest’s small footprint allows the “driver” to sit comfortably behind the rig. Straightpipes reports: “Shooters can ‘address the rifle’ just like a Light Gun — you’re not straining to wrap your arm around something overly massive. Anybody can shoot this, it’s a very easy gun to shoot.”
Is it accurate? In a word, “Yes”. Straightpipes doesn’t want to make claims before the rig has been tested in competition, but he says it has “shot groups at 600 and 1000 yards that would be very competitive.” We promised not to publish group sizes yet, but we can tell you that at 600 yards in good conditions it drilled some “scary small” 5-shot groups, well, well under 1/4 MOA.
Report by Forum Member Ian S. (aka “Nightowl”)
After taking a few years off from competitive shooting, in 2012 Mike Gaizauskas returned to the long-range rifle scene in a big way. During the course of the Virginia 1000-Yard Benchrest Club’s 2012 season, Mike set three new IBS 1K multi-match Aggregate records. Mike broke into the record-books using a very unique 300 WSM rifle that incorporates a lot “brainstorming” and help from Mike’s friends and colleagues. The record-setting rifle features a super-wide forearm which is also offset. (As viewed from the shooter’s position, the stock is wider on the left, off-setting the barreled action to the right). This Heavy Gun has proven to be super-accurate — Mike barely missed setting a new IBS 10-shot-group HG record by a couple thousandths.
IBS 1000-Yard Records by Mike Gaizauskas:
IBS 1000-Yard Heavy Gun Ten-Match Group Aggregate (5.6664 inches)
IBS 1000-Yard Heavy Gun Ten-Match Score Aggregate (95.30)
IBS 1000-Yard Heavy Gun Six-Match Group Aggregate (4.4935 inches)
Missed a Fourth IBS Record by a Whisker (or Two…)
In 2012, Mike came “oh-so-close” to breaking the current IBS 1000-Yard Heavy Gun 10-shot small group record of 3.044”. Using his offset HG shown below, Mike drilled a 3.046″ 10-shot group, just two thousandths of an inch (.002″) off the current record. FYI, the thickness of a typical human hair is .001″ — you can’t get much closer than that!
The record-setting gun was built with components gathered over time, which were then fitted into a new ultra-wide stock. Mike ordered two custom stock blanks from Richards Micro-Fit Stocks of Sun Valley, CA roughed to Mike’s specifications. One was for a Light Gun, and the other was for a Heavy Gun. Mike had been thinking about an offset design for some time. During the 2007 Nationals held at the Virginia 1000-Yard Club, Mike just happened to sit next to Dave Tooley for a day. Mike and Dave discussed at length Dave’s experiences and conclusions regarding offset stocks. Dave explained that an asymmetrical or offset forearm is designed to counter the longitudinal torque that occurs when the gun is fired. You can find these concepts featured a few years back in the 6mmBR.com Blog.
In addition to tapping into the mind of Dave Tooley, there was a LOT of debate among Mike’s friends regarding what shape and which side of the stock would work best to counter the barrel torque generated when launching a bullet utilizing a right-hand twist. Should the stock be wider on the left or wider on the right? Mike eventually decided to widen the forearm on the left side and apparently that was a wise decision — just check out the trophies this big rig has already hauled in:
Heavy Gun Is a 300 WSM
This record-setting Heavy Gun was chambered in 300 WSM by Mark King. The gun features a BAT Model M action mated with a 30″, 1:10″ twist Krieger chambered to a .338 neck and finished off with a muzzle brake of Mark’s design. The barreled action is held with a clamp-style barrel block. The stock incorporates stainless steel rails fashioned by Mike’s friend and machinist Steve Reimers.
… Stay tuned to the Daily Bulletin. We hope to provide a follow-up story with more photos and more information on Mike’s record-setting rifle (and the ultra-accurate ammo he feeds it).
This story first appeared last year. We’re featuring it again by popular request.
Some of our mechanically-skilled readers chamber their own barrels or bed their own stocks. But these are relatively simple tasks compared to the jobs of constructing an entire rifle plus building an advanced front rest from scratch. Well that’s exactly what Forum member Steve B. (aka Essexboy) did. He built his own rifle and an impressive twin-belt-drive pedestal rest. (Click photo below to see large version). And get this, Steve’s home-made rifle was victorious in its first-ever match. Steve reports: “I shot my first Comp with the rifle this weekend and managed to win with a score of 239-21!” (The match was shot at 300/500/600/1000/1100 with English scoring of 5 points for center bullseye).
Do-It-Yourself F-Open Rig from England
Steve, who hails from Essex in the UK, constructed virtually every component of his skeleton-style rifle except the 28″ HV Bartlein barrel (chambered as a 6mm Dasher) and the Tikka 590 donor action. Steve also did all the design and fabrication work on his one-of-a-kind front rest. Steve tells us: “Over the last year or so, I made this rifle stock and rest. I managed to make it all on a little Myford Lathe, as you can tell I’m no machinist but it saved me a load of money — so far I’ve got about $200 invested plus the barrelled action. The stock is aluminum except for the stainless steel bag runner. The rifle came in at one ounce under weight limit for F-Class Open division.” Steve did get help with the chambering and barrel-fitting, but he hopes to do all the barrel work himself on his next project.
The gun is very accurate. Steve notes: “I have shot the rifle to 1100 yards and it shoots well. Last time out the rifle dropped just one point at 1000 yards and 5 points at 1100 yards [English scoring system]. I know it’s not pretty, but it got me shooting long range F-Class for peanuts.” Message to Steve: Don’t worry how it looks. As another Forum member observed: “Any rifle that shoots well at 1100 yards is beautiful….”
Steve started with a Tikka 590 action: “The whole stock was made on a small (6.5×13) lathe and a vertical slide. This caused a few head scratching moments, figuring out how to hold the T6/HE30 alloy for the milling/turning operations, but it did teach me a few things. The hardest parts were clamping the longer sections (such as the fore-end) and keeping it all square. Due to the short cross-slide travel I had to keep re-setting the parts. I managed to keep all measurements to .0001″ (one thousandth). I’m most proud of the trigger guard (photo below). This took a full day but came out really well, even if I say so myself.”
Belt-Driven Front Rest
We’re impressed with Steve’s ingenious front rest. Steve explains: “The rest is belt-driven and still in the experimental stage — hence no powder coating or polishing yet. I may have gone over the top as the key moving parts (the pulleys) run on three (3) types of bearings: radial; reamed bush; and a ball race. The main post runs on a radial bearing and the feet even have bearings in them, so when I raise the main body up (for rough height adjustment) the foot stays static.”
Will Steve build another rifle? Steve says he will, and he’s upgraded his tools: “Since building the rifle I have acquired a bigger lathe (Harrison m250) and a milling machine. For the next project I hope to be able to do the barrel work (threading, chambering, crowning) as well.” The next gun might be another Dasher. Steve explains: “After extensive reading on AccurateShooter.com, I chose the 6mm Dasher chambering, as I have a shoulder problem and can’t shoot a rifle with a lot of recoil.”
Report by Richard King (King’s Armory, Texas; ‘Kings X’ on our Forum)
With all the talk from Vince Bottomley in the April issue of Target Shooter about aluminum stocks, I thought you might like to see my latest project. This is my personal gun, built the way I wanted it. I know it’s radical and some may not care for it. But it works.
This is pretty much an all-aluminum rifle. The action is a Kelbly F-Class with a Shilen stainless steel competition trigger. The scope is a 1″-tube Leupold 36X with a Tucker Conversion set in Jewell spherical bearing rings. The .223 barrel is Pac-Nor 3-groove, 1:6.5″-twist mounted in a “V”-type barrel block. The bipod has vertical adjustment only via a dovetail slide activated by a stick handle. It works like a joy-stick, but for vertical only. I adjust for windage by moving the rear sandbag.
The 30″ barrel is 1.250″ in diameter. With the barrel block forward, the vibrations should be at a low frequency. Instead of one long rod whipping, I now have two short rods (barrel haves) being dampened. This is my fourth barrel block gun. They work, but so does a good pillar-bedded action. I just do stuff a little different.
The vertical “keel” down the bottom of the stock stops the “spring” of a flat-bar stock. There is little, if any, noticeable flex before or during recoil. The long length of the stock, the fat barrel, and the forward-mounted barrel block work together to keep the gun from rising off the ground. BUT, remember this is a .223 Rem rifle. A .308 Win version might act very differently. I may try a .308-barreled action soon, just to see what happens. But I will stick with the .223 Rem as my choice for match shooting.
The offset scope idea came from a benchrest “rail” gun. In truth, the whole concept came from a rail gun — just adapted to being shot off a bipod. Sure it isn’t directly over the bore. It is about 1.5″ over to the left. So if you want the scope to be zeroed on the center of the target, you have to adjust for the offset. At 100 yards that is 1.5 MOA. But at 300 it is only 0.5 MOA, at 600 only a ¼-MOA, and at 1000 about 1 click on my scope.
What the offset DOES do for me is eliminate any cheek pressure. My cheek never touches the stock. Since this is only a .223 Rem, I don’t put and shoulder pressure behind it. And I don’t have a pistol grip to hang on to, but I do put my thumb behind the trigger guard and “pinch” the two-ounce trigger.
The offset scope placement could interfere with loading a dual-port action from the left. That’s not a problem for me as I set my spotting scope up on the left side very close to the rifle. I have plenty of time to reload from the right side while the target is in the pits being scored.
Again — this is my rifle. It is designed for my style of shooting. It is not meant to be a universal “fit all” for the general public. However, I will say the design is adaptable. I can easily convert the system to run in F-Open Class. I would drop a big-bore barreled action into the “V” block, slide on a heavier pre-zeroed scope and rings, add plates on the sides up front to bring the width to 3”, and maybe a recoil pad. It might be interesting to offset the wings up from to counter torque of the big bullets. But I would also have to offset the rear bag rider to get the gun to recoil straight back.
How the Gun Performs
I have had “T” to the range only twice for load development. It groups like my present barrel-blocked 223 F-TR gun. But it’s much easier to shoot and it only moves about 3/4” — straight back. I tried to build am omni-directional joy-stick bipod but I could not get all the side-to-side wiggle out of it. So I have set it up so it only moves up and down (horizontal movement is locked-out). As it works now, the joystick on the bipod lets me set elevation on the target quickly (with up/down adjustment). Then, to adjust for windage, I slide my rear bag side-to-side as needed. Once set, I just tickle the trigger and smile.
Gun Handling — Shoot It Like a Bench-Gun
I basically shoot the gun with no cheek or body contact. I don’t grip it, other than maybe a pinch on the trigger guard. The scope was offset to the left to help the shooter move off the gun and avoid the possibility of head/cheek contact with the stock.
Listen to Richard King Explain How He Shoots his ‘Texas-T’ Rifle:
[haiku url=”http://accurateshooter.net/Video/RichKingTalks.mp3″ Title=”Richard King Talks”]
Brownells now offers free firearms maintenance videos on the Brownells.com website and the Brownells YouTube channel. Brownells President/COO, Matt Buckingham says: “These videos are great for any firearm owner, regardless of skill or experience level. If you’re a new owner, they’ll be extremely helpful; if you’re a longtime gun owner, they’re a great refresher.”
These how-to videos guide viewers through the steps of proper disassembly, cleaning, lubrication, reassembly, and function testing of some of today’s most popular firearms. For each firearm type, a series of FOUR video segments are offered. These are professionally filmed, with multiple camera angles and detailed close-up shots.
Watch m1911 Pistol Disassembly Video (Part 1 of 4-part m1911 series)
Watch Remington 870 Shotgun Disassembly Video (Part 1 of 4-part Rem 870 Series)
Founded in 1939, Brownells is an Iowa-based, family-owned company that sells more than 75,000 firearms parts, gunsmithing tools, accessories, and reloading components. Brownells offers a lifetime guarantee on EVERY product sold. To place an order, or for more information, call 800-741-0015 or visit Brownells.com.
Secure Firearm Products (SFP) has introduced a new Spring Tester that measures the “pull weight” of a wide variety of springs used in handguns and rifles. With this new Spring Tester you can measure recoil springs, mainsprings, firing pin springs, and much more. The SFP Spring Tester comes with a digital scale. The complete Spring Tester kit (Model # 11490-SR-D) retails for $40.99.
The Spring Tester, which comes complete with a compact digital pull-weight scale, is simple to use. Just insert the spring on bolt, insert that assembly in the red tool housing, then attach the coupler and scale. Pull until proper compression length* is achieved, and record your reading. Note: the Spring Tester Tool is marked with a line at 1.625″ which is the Mil-Spec compression length of a 1911 recoil spring. The SFP Spring Tester currently ships with an adapter that lets you test small springs such as mainsprings, firing pin springs or other small springs used in pistols, rifles or revolvers.
*NOTE: The appropriate compression length varies with the spring and the application. You may need to get this compression length specification from the manufacturer.
SFP Spring Tester Demo Video
Why do you need a spring tester? SFP’s David Surgi explains: “It’s important to be able to sort and organize all of them properly and know that when a spring needs replacing, that you are putting in the right one with the proper tension.” Dan Kidder of Sportsman’s Warehouse concurs: “The Spring Tester from SFP gave me the ability to take a drawer full of recoil, main springs, firing pin springs and others, and easily identify their tension. I no longer have to try to label springs or worry about them getting in the wrong spot.”
Sometimes you’ll get a barrel that doesn’t stabilize bullets the way you’d anticipate, based on the stated (or presumed) twist rate. A barrel might have 1:10″ stamped on the side but it is, in truth, a 1:10.5″ twist or even a 1:9.5″. Cut-rifled barrels, such as Kriegers and Bartleins, normally hold very true to the specified twist rate. With buttoned barrels, due to the nature of the rifling process, there’s a greater chance of a small variation in twist rate. And yes, factory barrels can be slightly out of spec as well.
Before you purchase a bunch of bullets and set off to develop loads it’s wise to determine the true twist rate of your new barrel. Sinclair International, in its Reloading Press Blog provides a simple procedure for determining the actual twist rate of your barrel. Read on to learn how….
How Twist Rate Affects Bullet Stability
Most of you know that the twist of the rifling in the barrel is what puts spin on the bullet. As a bullet is pushed down the barrel and compressed into the rifling, the bullet follows the path or twist of the rifling. The combination of velocity and bullet spin is what stabilizes the bullet. Finding the twist rate for your barrel will help you in selecting appropriate weight bullets for your firearm. Remember, the general rule is that the faster the twist rate for a given caliber, the longer the bullet (of that caliber) you will be able to stabilize. (Generally speaking, a longer bullet will also be a heavier bullet, but the bullet geometry dictates the needed twist rather than the weight per se.)
Determining Barrel Twist Rate Empirically
Twist rate is defined as the distance in inches of barrel that the rifling takes to make one complete revolution. An example would be a 1:10″ twist rate. A 1:10″ barrel has rifling that makes one complete revolution in 10 inches of barrel length. Rifle manufacturers usually publish twist rates for their standard rifle offerings and custom barrels are always ordered by caliber, contour, and twist rate. If you are having a custom barrel chambered you can ask the gunsmith to mark the barrel with the twist rate.
Sinclair’s Simple Twist Rate Measurement Method
If are unsure of the twist rate of the barrel, you can measure it yourself in a couple of minutes. You need a good cleaning rod with a rotating handle and a jag with a fairly tight fitting patch. Utilize a rod guide if you are accessing the barrel through the breech or a muzzle guide if you are going to come in from the muzzle end. Make sure the rod rotates freely in the handle under load. Start the patch into the barrel for a few inches and then stop. Put a piece of tape at the back of the rod by the handle (like a flag) or mark the rod in some way. Measure how much of the rod is still protruding from the rod guide. You can either measure from the rod guide or muzzle guide back to the flag or to a spot on the handle. Next, continue to push the rod in until the mark or tape flag has made one complete revolution. Re-measure the amount of rod that is left sticking out of the barrel. Use the same reference marks as you did on the first measurement. Next, subtract this measurement from the first measurement. This number is the twist rate. For example, if the rod has 24 inches remaining at the start and 16 inches remain after making one revolution, you have 8 inches of travel, thus a 1:8 twist barrel.
This rifling illustration was created by Danish graphic artist Erik Dahlberg. It is published here courtesy FireArmsID.com, an excellent website for forensic firearms examiners.
Canadian Fred Harvey of Star Shooter Precision recently posted photos of an interesting metal-stocked F-TR rifle, fitted with a Star Shooter CF-SS Bipod with carbon-fiber legs. This handsome .308 Winchester rifle features a Barnard S action, 30″ Krieger barrel (1:11.25″ twist), and aluminum stock/chassis from Dolphin Gun Company in the UK.
The all-up weight of this rig, including the Star Shooter bipod and mounting rail is 17 pounds, 15 ounces. (F-TR weight limit is 8.25 kgs, approx. 18.15 pounds). Gunsmith was Ian Robertson.
Dolphin Gun Company Aluminum F-TR/Tactical Rifle Stock
Dolphin’s modular, CNC-crafted F-TR/Tactical stocks are fully adjustable. Fore-ends are interchangeable and the pistol grip even adjusts for length of pull. Dolphin offers single shot and repeater inlets for Rem 700-style actions, Barnard S & SM actions, RPA Quadlite actions, plus BAT VR and Savage actions. Three types of fore-ends are available: short tactical style, long F-TR style, and a wide F-Open style. Repeater versions accept AI magazines. Dolphin claims the repeaters “feed faultlessly with any action fitted”. The aluminum Dolphin F-TR/Tactical stock comes with an adjustable buttplate fitted with Morgan Recoil pad. The bag-rider height also adjusts. These stocks sell for £630 (about $960 USD) with either Dura-coat or hard-anodized finish. A variety of anodizing colors are offered.