.223 Rem for Long Range Palma, by John Whidden (5-Time Nat’l LR Champion)
We’ve seen quite an amount of interest in recent years in .223s for Long Range Palma shooting. Yes, the .223 Remington is a pretty light cartridge for long range use, but the specific rules of Palma shooting make it a choice worth considering.
Back in 2019, the Int’l Confederation of Fullbore Rifle Associations (ICFRA), the international governing body for Palma shooting, made a rule change allowing .223 Rem rifles to use bullets of less than 91 grains. Previously the rule allowed the use of bullets less than 81 grains in the .223 Rem, and we have long had the popular option of .308s shooting bullets less than 156 grains. These heavier bullets such as the 85.5gr Berger LR Hybrid and 90gr Berger VLD make the .223s quite competitive in the wind with the old standby .308 Winchester. The .223 does hold the obvious advantage of much lower recoil than the .308. [Editor: The reduced recoil is quite noticeable in the video below where John is shooting his .223 Rem rifle.]
John Whidden Shoots .223 Rem Palma Rifle with 90gr Berger VLDs
Watch video at 00:25 and you’ll see the recoil of Whidden’s .223 Rem Palma rifle is significantly less than a .308 Win Palma rig. John joked: “With the .223 Rem there is just a pop and a wiggle after the shot.”
.223 Rem Palma Rifle — Barnard Action, Tec-Hro Stock
The Barnard P action imported by Whidden Gunworks is the foundation for many winning Palma rifles. As soon as our USA shooters returned from the New Zealand Palma match in 2019 they were immediately requesting bolts to convert their actions to .223 Remington.
Given all of this interest in the .223 Rem, I decided to build one myself and see if all of these theories about wind performance held water. Starting with my Barnard P action, I worked with Tec-Hro in Germany to use one of their Fanatic stocks for the project. The Fanatic is a modern aluminum stock suitable for prone or Three Position use. The stock uses adapter blocks to work with a wide variety of rimfire actions such as Anschutz, Walther, and Feinwerkbau. As far as I know we were the first to test it out for centerfire use. After shooting the stock with my .308 Win barreled action installed to refine a few details and ensure the stock would stand up to recoil, I then mounted my .223 Rem barreled action and went to the range.
Prior to my range visit a decision was made concerning bullets and twist rate. After discussion with Mark Buettgen at Bartlein Barrels I ordered two barrels — a 1:7″-twist and also a 1:6.25″-twist. Mark was looking for some data using the Sierra 90gr MatchKing bullet and we expected that the faster twist rate might give the best success with that MatchKing bullet. When the barrels arrived they were chambered and installed on the rifle.
John uses a Warner rear adjustable sight with a Centra front sight.
Fast Twist-Rate Barrels for Long .223-Caliber Bullet
First up the 1:6.25″-twist barrel was installed and testing commenced. The barrel shot extremely well right out of the gate. All loads used Lapua brass and Vihtavuori N140 powder. I tested the Berger 85.5gr and 90gr bullets as well as Sierra 90gr and 95gr bullets. Testing with the 6.25-twist barrel went well with both of the Berger bullets looking especially good. Later the 1:7″-twist barrel was mounted and tested.
While both barrels were very accurate we decided that the 1:6.25″-twist barrel outshined the 1:7″-twist tube. Now we all know that some barrels are just a little more accurate than others. With such a small sample of data here (just two barrels) I’m not saying that a 1:6.25″-twist is decidedly better. In fact we have a number of customers shooting 7-twist barrels who are shooting them very well. With this particular rifle however, the 6.25-twist seems to be the more accurate of the two.
.223 Rem Load Development for Palma Competition
The load I settled on is Lapua brass, Vihtavuori N140 powder, and Berger 90 grain VLDs which I moly-coat. I soft-seat the bullets into the lands with only .001″ neck tension or a little less.
Why the Berger 90gr VLD? The secret sauce is that the 90gr VLD is much superior in the wind after we point it up with the Whidden Pointing Die. The 85.5gr Hybrid bullet comes from Berger with this treatment already done while the 90gr VLD does not. When the 90-grainer is pointed up, the wind drift is a few percent better than the 85.5, given the velocities that I feel comfortable achieving with the rifle.
I settled on 2840 fps for the 90gr VLD and 2880 fps for the 85.5gr Hybrid from a 32″ barrel. When pointed up, the 90-grainer shoots flatter to 1000 yards by 1 MOA which indicates a G7 BC of .289 in my combination. Wind Drift in a 10 mph direct crosswind at 1000 yards is 70.8″ with this 90gr combination compared to 76.8″ for the 85.5gr load.
Testing in Competition — at Camp Perry
This past August 2021 at the CMP Long Range National Championships at Camp Perry I finally had the chance to shoot the rifle on a big stage. Winds that day were from almost directly 12:00 to about 1:30 switching headwinds. Velocity was around 8-10 mph meaning not the easiest or the hardest of conditions. I managed a third place finish in the Palma match. That proves the .223 Rem is definitely competitive in elite Palma events.
.223 Rem Performance in the Wind
My sense of the .223 Rem’s wind performance was that it was in line with the performance I’d expect from my .308 Win Palma gun. Of course the lack of recoil made the .223 Rem much easier to shoot well.
How to Order a Rifle Like This Whidden Gunworks can build a rifle like this for Palma competitors who want to move to .223 Rem. John tells us: “We’ve built a number of these combinations of the Barnard P action, Tec-Hro Fanatic stock, and Bartlein barrel. They all shoot incredibly well and the ergonomics are top notch. One of the good points is that the current price of $3875.00 (without sights) makes it a bargain for a top-tier Palma rifle.”
About John Whidden
5-Time National Long Range Champion
John Whidden is founder and owner of Whidden Gunworks and a lifelong competitive shooter. Major shooting accomplishments include being a 5-Time U.S. National Long Range Champion, winner of the Australia National Queen’s Prize, and member of three USA Palma Teams. John is currently active in Long Range Highpower, 300 Meter Prone, and Smallbore prone events. John tells us that one secret of his success is having top equipment: “The mental component of Long Range competitive shooting is always challenging but having tremendous confidence in the accuracy of your equipment is a huge benefit. There’s nothing to start your Palma match off well like knowing that you are shooting the most accurate Palma rifle you’ve ever owned.”
Whidden Gunworks stands ready to help with your shooting and reloading needs. Whidden Gunworks specializes in custom bolt action rifles, reloading dies, other reloading tools, and reloading components. Well known for match-grade custom rifles and high-quality reloading dies, Whidden Gunworks’ growing lineup includes components from Berger, Lapua, Vihtavuori, and SK rimfire ammunition. Learn more by visiting www.WhiddenGunworks.com.
This illustration shows headspace measurement for the popular .308 Winchester cartridge, which headspaces on the shoulder. Image copyright 2015 Ultimate Reloader.
In this Brownells Tech Tip Video, Brownells gun tech Steve Ostrem explains what headspace is and why it’s one of the most critical measurements for nearly all firearms. Even if you’re an experienced rifle shooter, it’s worth watching this video to refresh your understanding of headspace measurements, and the correct use of “GO” and “NO-GO” gauges.
Headspace Definition
In firearms, headspace is the distance measured from the part of the chamber that stops forward motion of the cartridge (the datum reference) to the face of the bolt. Different cartridges have their datum lines in different positions in relation to the cartridge. For example, 5.56x45mm NATO ammunition headspaces off the shoulder of the cartridge, whereas .303 British headspaces off the forward rim of the cartridge. If the headspace is too short, ammunition that is in specification may not chamber correctly. If headspace is too large, the ammunition may not fit as intended or designed and the cartridge case may rupture, possibly damaging the firearm and injuring the shooter. (Source: Wikipedia)
Problems Caused by Too Much Headspace
Excessive headspace issues can include: light primer strikes, failure to fire, bulged/blown cases, case separations, split shoulders, or unseated primers after firing. Case ruptures caused by excessive headspace can lead to catastrophic failures causing serious injury. That is why headspace is such an important measurement.
Problems Cause by Too Little Headspace
Insufficent (or excessively tight) headspace can prevent the firearm from going into battery, resulting in failure to fire or deformation of the cartridge case. Various feeding and functioning problems can be caused by cases with too little headspace, even if a round can be chambered (with effort).
Headspace Gauges
Headspace is measured with a set of two headspace gauges: a “Go” gauge, and a “No-Go” gauge. Headspace gauges resemble the cartridges for the chambers they are designed to headspace, and are typically made of heat-treated tool steel. Both a “Go” and a “No-Go” gauge are required for a gunsmith to headspace a firearm properly. A third gauge, the “Field” gauge, is used (as the name implies) in the field to indicate the absolute maximum safe headspace. This gauge is used because, over time, the bolt and receiver will wear, the bolt and lugs compress, and the receiver may stretch, all causing the headspace to gradually increase from the “factory specs” measured by the “Go” and “No-Go” gauges. A bolt that closes on “No-Go” but not on “Field” is close to being unsafe to fire, and may malfunction on cartridges that are slightly out of spec. (Source: Wikipedia)
To learn more, read Brownell’s article Headspace Gauges and How to Use Them. Among other things, this explains the relative lengths of “Go”, “No-Go”, and “Field” gauges. The “Field” is actually the longest: “The GO gauge corresponds to the SAAMI minimum chamber length, while the FIELD gauge usually matches the maximum chamber depth, or slightly less. NO-GO gauges are an intermediate length between minimum and maximum, that, technically, is a voluntary dimension. A firearm that closes on a NO-GO gauge and does not close on a FIELD gauge may not give good accuracy and may have very short cartridge case life from the ammunition re-loader’s standpoint.”
While AccurateShooter.com focuses on rifles, we know that a large percentage of our readers own handguns, with 1911-style pistols being particular favorites. For you 1911 owners, here are six short videos from Brownells showing how to customize a 1911-style pistol with after-market upgrades.
How to Accessorize Your 1911
This six-part series by Brownells provides step-by-step instruction on how to accessorize your 1911. The videos cover changing out the mainspring housing, magazine release, slide release, hammer, guide rod, and installing a group gripper. If you want to upgrade your 1911, these videos are worth watching.
Model 1911 Components and Cycling — Cut-Away Animation Video
If you’re not familiar with M1911 type single-action pistols, this video animation provides an inside look at the M1911’s components and shows how the M1911 cycles:
Top is a CZ 457 MTR; middle Anschutz with BR stock; bottom is Bergara B14R in DPT Chassis.
With the variety of rimfire disciplines, from cowboy action to Olympic three-position smallbore, there are countless different rimfire designs on the market — bolt guns, lever guns, single-shots, toggle-links and more. These may shoot the same ammo, but they certainly vary in looks and ergonomics. This is testimony to human creativity.
In our Shooters’ Forum, you’ll find a long-running thread showcasing rimfire rifles for plinking, hunting, 3P Target Shooting, Silhouette, Rimfire F-Class, NRL22 and more. Here are some of the notable recently-posted rifles in that Forum thread, with brief build/component details.
ARA Benchrest Rifle with Stiller Action, Shilen Ratchet Barrel
Forum member Peebles24 showcased his cool flame-paint-job .22 LR benchrest rifle against a scenic, snowy background (never too cold to shoot right?). “I had a new rifle built this past fall by Mark Penrod at Penrod Precision. Stiller 2500X action, Shilen ratchet barrel, Jewell trigger, McMillan stock, Harrell’s tuner, Sightron SIII 10-50×60mm glass. I’m shooting it off my Arnold Machine one-piece rest made locally by Cliff Arnold. I visited the Lapua Testing Center East and got a case of Midas+.” For ammo testing results, click photo at right.
In late April the gun competed in its first ARA benchrest match in Wabash, Indiana.
Beautiful MasterClass-Stocked Rifle for Rimfire F-Class
Here is a handsome rifle belonging to Forum member Redd. Set up for prone Rimfire F-Class-style competition, this rig features a Shilen Ratchet barrel with Erik Cortina Tuner fitted to a Stiller 2500X action. It boasts a beautiful MasterClass figured Walnut stock and rides on a SEB Joy-Pod bipod up front. The optic is a Nightforce 40x45mm Competition.
CZ 457 .22 Magnum Transformed with KRG Bravo Stock
Forum member JAS-AS purchased a .22 Magnum CZ which he revived as a training rig with a new stock. He posted: “I use a CZ457 in .22 Magnum mainly as a trainer — bipod and rear bag kind of stuff. It has evolved over the last year or so. Next change will be a Lilja barrel. This because it can shoot brilliantly (at times) but not consistently. And accuracy degrades as it gets minimally dirty. Also, it doesn’t like 40gr rounds — the groups open up to 1.5 MOA. It’s at its best with 30 and 35 grain rounds running at up to 2250 fps. I believe that to be a twist-rate issue.”
The “Before” photo shows the rifle “as purchased” with a Nikon Monarch 4-16x42mm mildot scope. The “After” image shows the CZ 457 as modified. JAS-AS notes: “I added a bunch of stuff: KRG Bravo stock, Vortex Strike Eagle 5-25x56mm FFP scope, new bipod and Precision Underground bag, trigger spring. With this setup I shoot at 100 yards+ exclusively.” Show at right is a 9-shot group with the rifle at 100 yards. Three-shot groups at 100 have been below half-MOA.
Savage Mark II Squirrel/Field Rifle
This Savage Mark II rifle isn’t fancy, but it has brought much satisfaction to its owner, Forum member “Ohio Varmint Shooter”. He posted: “Just a nice field gun. Less than $200 (without scope). Cheap wooden stock, thin pencil barrel. My squirrel/field gun. There is absolutely nothing special about this… except it’s lefthanded. It shoots fine, preferring CCI standard velocity rounds. I did splurge and put a more-than-needed scope on it. Most scopes with fixed parallax (in this category), have it fixed at 50 yards. I wanted variable parallax so I could set it at 35 yards. I don’t know if it really makes any difference, but I do try to go for accurate head shots. The scope is also a little overkill in magnification, but it does help with the head shots and my aging eyes.”
“As a youth in the 70s, I always dreamed of a left-handed bolt. So getting back into shooting/hunting about 8 years ago, I was delighted to discover this gun. Growing up I had a semi-auto 22, but being a lefty … it would spit powder on my face.” — Ohio Varmint Shooter
Tikka T1x Action in Eliseo Competition Machine Chassis
Here is Gary Eliseo’s personal Rimfire Match Target Rifle with Tikka T1x action. The T1x action is carried in Competition Machine Rimfire Chassis. Gary also posted some recent 100-yard groups, using SK rifle match ammo in this rifle. Gary runs Competition Machine LLC and produces the chassis system for this cool rig, along with outstanding Across-the-Course, High Power, and F-Class chassis systems for rimfire and centerfire rifles.
Vudoo Action Benchrest Rifle with Benchmark 3-Groove Barrel
Here is a classy benchrest rig belonging to Forum member FCJIM. It features a Vudoo LBRP action, Benchmark 3-groove barrel, Harrell’s Precision tuner, NightForce Benchrest scope, and McMillan Edge stock. The stock work was done by Doan Trevor, while FCJIM did the metal work himself, using a Nevius reamer. This rig likes to shoot ELEY Black and Lapua Midas+ ammo.
Last but not least, here is a “blast from the past”. This classic lever-action single shot is crafted by CPS Rifles (Paul Shuttleworth), a boutique gun-maker specializing in single-shot rifles, particularly reproductions of the Stevens 44 1/2. Note the richly-figured wood and the lovely color case-hardening on the receiver. There is a dual Set Trigger system. You pull one trigger through a relatively long stroke until it clicks. The the second trigger breaks the shot (and drops the hammer) with just a few ounces of pull weight. This rig, fitted with MPA Vernier-type tang sights, belongs to Forum member “Mills” from Texas.
Note the owner’s name, “S. Limbourne” was engraved on the bolt release (and trigger guard, see below).
Competition rifles don’t need to be beautiful, as long as they shoot. But who doesn’t like a spectacular figured-wood stock, particularly when it is combined with a superb custom action and a tack-driving barrel. This custom .284 Winchester F-Class Open division rig was crafted by gunsmith Thomas “Speedy” Gonzalez for competitive shooter Scott Limbourne. The handsome Bacote wood stock comes from Cerus Rifleworks, while the action is a polished Borden RBRP BRMXD. Two Brux 1:9″-twist barrels were chambered for the project, both finished at 32″. The stock is also fitted with a R.A.D. Recoil System. This rig has top-of-the-line hardware all around.
Action: Borden BRMXD – Polished
Rail: 20 MOA Polished
Chambering: .284 Winchester
Trigger: Jewell BR – Blueprinted
Barrel: (2x) Brux 32″ 1:9″ Twist
Stock: Cerus F-Open in Exhibition Grade Bacote
Recoil System: R.A.D. System
Extras: Carbon Fiber Tunnel Plate, Custom Engraving Work on Action, Trigger Guard, and Bolt Release.
You’ll find other impressive rigs on Speedy’s Facebook Page. If you’d like a superb custom rifle like this, call Thomas “Speedy” Gonzalez at 972-672-6630, or send email to: speedy.godzilla [at] msn.com.
Can you guess what your next barrel will weigh? In many competition disciplines, “making weight” is a serious concern when putting together a new match rifle. A Light Varmint short-range Benchrest rifle cannot exceed 10.5 pounds including scope. An F-TR rifle is limited to 18 pounds, 2 oz. (8.25 kg) with bipod.
One of the heaviest items on most rifles is the barrel. If your barrel comes in much heavier than expected, it can boost the overall weight of the gun significantly. Then you may have to resort to cutting the barrel, or worse yet, re-barreling, to make weight for your class. In some cases, you can remove material from the stock to save weight, but if that’s not practical, the barrel will need to go on a diet. (As a last resort, you can try fitting a lighter scope.)
Is there a reliable way to predict, in advance, how much a finished barrel will weigh? The answer is “yes”. PAC-NOR Barreling of Brookings, Oregon has created a handy, web-based Barrel Weight Calculator. Just log on to Pac-Nor’s website and the calculator is free to use. Pac-Nor’s Barrel Weight Calculator is pretty sophisticated, with separate data fields for Shank Diameter, Barrel Length, Bore Diameter — even length and number of flutes. Punch in your numbers, and the Barrel Weight Calculator then automatically generates the weight for 16 different “standard” contours.
Calculator Handles Custom Contours
What about custom contours? Well the Pac-Nor Barrel Weight Calculator can handle those as well. The program allows input of eight different dimensional measurements taken along the barrel’s finished length, from breech to muzzle. You can use this “custom contour” feature when calculating the weight of another manufacturer’s barrel that doesn’t match any of Pac-Nor’s “standard” contours.
Caution: Same-Name Contours from Different Makers May Not be Exactly the Same
One key thing to remember when using the Barrel Weight Calculator is that not all “standard” contours are exactly the same, as sold by different barrel-makers. A Medium Palma contour from Pac-Nor may be slightly different dimensionally from a Krieger Medium Palma barrel. When using the Pac-Nor Barrel Weight Calculator to find the weight of a barrel from a different manufacturer, we recommend you get the exact dimensions from your barrel-maker. If these are different that Pac-Nor’s default dimensions, use the “custom contour” calculator fields to enter the true dimensions for your brand of barrel.
Smart Advice — Give Yourself Some Leeway
While Pac-Nor’s Barrel Weight Calculator is very precise (because barrel steel is quite uniform by volume), you will see some small variances in finished weight based on the final chambering process. The length of the threaded section (tenon) will vary from one action type to another. In addition, the size and shape of the chamber can make a difference in barrel weight, even with two barrels of the same nominal caliber. Even the type of crown can make a slight difference in overall weight. This means that the barrel your smith puts on your gun may end up slightly heavier or lighter than the Pac-Nor calculation. That’s not a fault of the program — it’s simply because the program isn’t set up to account for chamber volume or tenon length.
What does this mean? In practical terms — you should give yourself some “wiggle room” in your planned rifle build. Unless you’re able to shave weight from your stock, do NOT spec your gun at one or two ounces under max based on the Pac-Nor calculator output. That said, the Pac-Nor Barrel Weight Calculator is still a very helpful, important tool. When laying out the specs for a rifle in any weight-restricted class, you should always “run the numbers” through a weight calculator such as the one provided by Pac-Nor. This can avoid costly and frustrating problems down the road.
ARs and Narrow-Forearm Sporters Benefit from Front Bag-Rider Blocks
Whidden Gunworks offers a smart product that will enhance the bench-rested accuracy of any rifle with an accessory rail on the forearm. The Whidden Track Plate fits securely in the forearm accessory rail on prone, cross-the-course, tactical, and Palma rifles. These guns typically have a narrow and/or rounded fore-end so they rock and wobble when used with a front pedestal rest. The TrackPlate cures that. Once installed it provides a rock-solid, 2.9″-wide platform that mates perfectly with a benchrest-type front sandbag. This gives sling-shooters maximum stability when testing loads or zeroing their sights or scope. Plus you can now shoot F-Class competitively with a prone gun. (The 2.9″ width is 100% legal for F-Open).
The Track Plate is light-weight, has catamaran-style runners to aid tracking and prevent rocking, and can be easily stowed in a range bag. The Track Plate fits BOTH Anschutz and American style forends and is made in the USA of machined aluminum. The Track Plate is available from Whidden Gunworks for $49.50.
Plate designer (and 5-Time Nat’l LR Rifle Champion) John Whidden says: “The Plate is great for any rifle with a rail whether it ís smallbore, centerfire, or an air gun. Now you can try F-Class with your favorite prone rifle: the Plate has a perfect low-drag finish for riding a rest or sandbags and is competition legal.”
Bag-Riders for AR-Platform Rifles from EGW
AR owners should check out the 3″-wide Delrin bag-rider from Evolution Gun Works (EGW). There are two versions, one for front Picatinny Rails, and another that mounts via sling swivel studs. These EGW Bag-Riders were developed expressly to fit the fore-ends of ARs. The front bag-riders are contoured to match the handguard profile so they fits securely with no wobble.
The $49.99 EGW Picatinny Rail front Bag-Rider simply slides on your under-forearm rail and there is a a tension bolt. Attachment is quick and easy. Or, if your AR has no rail get the original $39.99 EGW front Bag-Rider that attaches to a front sling swivel stud anchor. That allows it to mount as easily as a Harris bipod — no rail needed! Just unscrew the swivel stud, put the front bag-rider in place and attach one hex-head machine screw.
Also with the two front Bag-Riders, EGW offers a Rear Bag-Rider for ARs that attaches via the sling swivel anchor. Overall, it is a slick system. Front and rear bag-riders can be attached in a couple of minutes. The Delrin blocks slide easily in the bags and make the gun ultra-stable. The gun tracks straight back.
With barrels, one wonders “Can a little more length provide a meaningful velocity gain?” To answer that question, Rifleshooter.com performed an interesting test, cutting a .308 Win barrel from 28″ all the way down to 16.5″. The cuts were made in one-inch intervals with a rotary saw. At each cut length, velocity was measured with a Magnetospeed chronograph. To make the test even more interesting, four different types of .308 Win factory ammunition were chronographed at each barrel length.
This is a very useful test is you’re thinking about building a .308 Win hunting rifle, or perhaps thinking of going shorter for your F-TR rifle to save weight.
Test Barrel Lost 22.7 FPS Per Inch (.308 Win Chambering)
How much velocity do you think was lost, on average, for each 1″ reduction in barrel length? The answer may surprise you. With a barrel reduction from 28″ to 16.5″, the average speed loss of the four types of .308 ammo was 261 fps total. That works out to an average loss of 22.7 fps per inch. This chart shows velocity changes for all four ammo varieties:
Summary of Findings:
The average velocity loss per inch, for all four ammo types combined, was 22.7 FPS. By ammo type, the average FPS loss per inch was: 24.6 (Win 147 FMJ), 22.8 (IMI 150 FMJ), 20.9 (Fed GMM 168gr), and 22.5 (Win 180PP).
Interestingly, these numbers jive pretty well with estimates found in reloading manuals. The testers observed: “The Berger Reloading manual says for the 308 Winchester, ‘muzzle velocity will increase (or decrease) by approximately 20 fps per inch from a standard 24″ barrel’.”
How the Test Was Done
The testers described their procedure as follows: “Ballistic data was gathered using a Magnetospeed barrel mounted ballistic chronograph. At each barrel length, the rifle was fired from a front rest with rear bags, with five rounds of each type of ammunition. Average velocity and standard deviation were logged for each round. Since we would be gathering data on 52 different barrel length and ammunition combinations and would not be crowning the barrel after each cut, we decided to eliminate gathering data on group sizes. Once data was gathered for each cartridge at a given barrel length, the rifle was cleared and the bolt was removed. The barrel was cut off using a cold saw. The test protocol was repeated for the next length. Temperature was 47° F.”
CLICK HERE to Read the Rifleshooter.com Test. This includes detailed charts with inch-by-inch velocity numbers, multiple line charts, and complete data sets for each type of ammo. Rifleshooter.com also offers ballistics graphs showing trajectories with different barrel lengths. All in all, this was a very thorough test by the folks at RifleShooter.com.
Much Different Results with 6mmBR and a Longer Barrel
The results from Rifleshooter.com’s .308 barrel cut-down test are quite different than the results we recorded some years ago with a barrel chambered for the 6mmBR cartridge. When we cut our 6mmBR barrel down from 33″ to 28″, we only lost about 8 FPS per inch. Obviously this is a different cartridge type, but also our 6mmBR barrel end length was 5″ longer than Rifleshooter.com’s .308 Win start length. Velocity loss can be more extreme with shorter barrel lengths (and bigger cartridges). Powder burn rates can also make a difference.
Our friend Robert Whitley of ARX Enterprises LLC has learned, through careful measurement and testing, that some barrels threaded 5/8″ x 24 TPI at the muzzle may not deliver optimal accuracy. The reason is that the end of the barrel can bell out slightly, like a trombone, because too much steel has been removed. This is particularly true with .30-caliber barrels, but it can also be a problem with smaller caliber barrels (even 6mm). Robert demonstrates this phenomenon in the video below. All gunsmiths, and anyone considering threading a barrel, should watch the video. At 1:00 – 1:30 Robert gauges a 5/8″ x 24-threaded .30-Caliber barrel. You can see the belling effect clear as day.
“When setting up a commercial barrel in the lathe, we noticed that the maximum-sized bushing that would fit in the bore at the chamber end was almost .0015” smaller [than what would fit] at the muzzle. That precipitated my pin-gauging of a number of different commercial barrels that were threaded for 5/8” x 24 tpi. What I found is what’s shown on the video.” – R. Whitley
Solve Problem with a Larger Thread Diameter
If 5/8″ x 24 threading is potentially harmful to accuracy, is there a solution? Yes, you simply need to leave a little more steel on the barrel. (See Video starting at 02:40.) Frank Green of Bartlein barrels states: “We get these questions all the time. I say run the largest thread diameter that is possible.” Robert Whitley has found that a 3/4″ x 28 TPI threading does not cause the “belling effect”. Accordingly Robert recommends 3/4″ x 28 if you need to thread your barrel for a muzzle brake or suppressor. Robert explains: “We only make 3/4” x 28 TPI muzzle brakes and that’s what we recommend to customers.”
“See how much meatier the 3/4″ threading is vs. the 5/8″. The 3/4″ threading offers a lot more metal around the bore. There’s a lot less opportunity for the bore to become bell-mouthed…” – Robert Whitley
Barrel Threading Diameter — What’s Important to Know
By Robert Whitley
In truth, the 5/8” x 24 TPI threading never came out of any accuracy-based think tank or set-up, it’s a military .30-Cal threading for barrels that someone has to carry around (they needed to keep the barrel weight down so it was smaller in diameter and the threading had to work with that situation). People have somehow assumed because the military uses that threading for certain things that it must mean that it’s also fine for a highly accurate rifle too, but that’s not really correct.
I don’t think there is any better and realistic option than the 3/4″ muzzle threading, and we also do it so there is no relief cut behind the threads on the barrel (i.e. put the relief cut on the brake or jam nut, don’t chop down on the muzzle of the barrel). For some reason many have a hard time grasping that the metal at the muzzle end of a rifle is “sacred” and you should not cut it down any more than absolutely necessary. A little threaded pencil diameter nub on the end of a barrel is not ideal for accuracy especially if it’s threaded and you need to torque on it. I cringe when I see a barrel with something like an MTU or Heavy Varmint contour, only to have an itty-bitty pencil thin threaded nub right at the muzzle so someone can “screw on a can” or a muzzle brake.
Lessons Learned Over the Years
A number of years ago I did a 30BR rifle project with Craig Kostyshyn who was big in the 30BR game and he made some of the best 30BR rifle barrels for benchrest competition. When I did the project I wanted a medium-heavy Palma type contour barrel I could use and also have a muzzle turndown for a front sight band. When he found out I was going to have the muzzle turned down he said “whoa, I need to provide for that when I make the barrel because if you turn the front down later you’ll be shooting a trombone” (i.e. the muzzle bore dimension would open up).
What he did was rough contour the barrel with the turndown (about .010” oversize) before he lapped the barrel, then when he lapped the barrel he took it easy in the muzzle area and worked the back of the barrel more. I thought he was a little bit excessive in his concerns but the barrel shot great and I wasn’t going to argue with him, after all he was shooting groups in the ones. I kind of just filed that away and never thought about it until recently when I went to have Fred from Sabreco do some chamber re-work on a commercial .30-caliber barrel I had. When setting up the barrel in the lathe and indicating things Fred noticed that the maximum-sized bushing that would fit in the bore at the chamber end was almost .0015” smaller [than what would fit] at the muzzle and he mentioned it to me. That precipitated my pin-gauging of a number of different commercial barrels I had that were threaded for 5/8” x 24 TPI. What I found is what’s shown on the video.
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Sako, and its subsidiary Tikka, make some of the finest hunting rifles you can buy. These offer smooth actions, and very good out-of-the-box accuracy for factory rifles. In addition, Sako and Tikka now offer high-tech carbon fiber stocks, along with Sako’s handsome wood stocks. With the three videos showcased today, you get a virtual tour of the Sako/Tikka production facilities in Finland.
In this informative video, the Canada in the Rough team tours the Sako/Tikka factory in Riihimäki, Finland. All aspects of the production process are covered — crafting actions, barrel-making, stock fitting and more. It was interesting to see the hammer-forging process for barrels, and the exacting measurements that are performed on the actions and bolt assemblies. If you have an interest in rifle production and the type of modern, computer-controlled machinery now being used, definitely watch this video.
Visit to SAKO/Tikka Carbon Fiber Stock Factory
This Sako-produced video shows how the company’s modern carbon-fiber stocks are produced. The stock production process is highly automated, to ensure that the finished stocks have very precise dimensions. These carbon Sakos are some of the nicest carbon-fiber stocks we’ve ever seen.
SAKO Factory Tour in Riihimäki Finland
In this segment, huntress and outdoor video host Mia Anstine tours the Sako manufacturing facility in Riihimäki, Finland. This video covers both firearms production and ammunition manufacturing. In a follow-up video Mia tests Sako rifles and Sako ammunition at a Finland range. Mia also reported on her Sako factory tour in the Beretta Blog. She notes: “Sako built its original manufacturing facility during World War I. To this day they still utilize the original buildings but have also grown over the years to include larger production areas and updated equipment.”
Canada in the Rough Video Tip from Boyd Allen — we welcome reader submissions
Testing in Competition — at Camp Perry
About John Whidden
Headspace Gauges
Forum member JAS-AS purchased a .22 Magnum CZ which he revived as a training rig with a new stock. He posted: “I use a CZ457 in .22 Magnum mainly as a trainer — bipod and rear bag kind of stuff. It has evolved over the last year or so. Next change will be a Lilja barrel. This because it can shoot brilliantly (at times) but not consistently. And accuracy degrades as it gets minimally dirty. Also, it doesn’t like 40gr rounds — the groups open up to 1.5 MOA. It’s at its best with 30 and 35 grain rounds running at up to 2250 fps. I believe that to be a twist-rate issue.”
Can you guess what your next barrel will weigh? In many competition disciplines, “making weight” is a serious concern when putting together a new match rifle. A Light Varmint short-range Benchrest rifle cannot exceed 10.5 pounds including scope. An F-TR rifle is limited to 18 pounds, 2 oz. (8.25 kg) with bipod.
