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.
NOTE: This is a copyrighted article. Do not reproduce or re-link more than 75 words without written permission from AccurateShooter.com.
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A while back, the Precision Rifle Blog conducted a fascinating study of Muzzle Brakes. PRB figured out a way to show the actual “blast pattern” of gasses ejecting from the ports of muzzle brakes. The result was a fascinating (and eye-catching) series of images revealing the distinctive gas outflows of 20+ different types of muzzle brakes. If you are considering buying and installing a muzzle brake on your rifle, you should definitely review this important PRB Muzzle Brake Test.
For a prone shooter, particularly on dusty, dirty or sandy ground, muzzle blast is a major bummer. Muzzle blast can be very disturbing — not just for the trigger-puller but for persons on either side of the gun as well. Some muzzle brakes send a huge shockwave back towards the shooter, and others send blast towards the ground, kicking dirt and debris into the prone shooter’s face. If there was a way to illustrate those factors — shockwave and debris — that might help shooters select one brake design over another.
Cal Zant at PrecisionRifleBlog.com applied a unique blend of creativity and resourcefulness to try to answer that question for 20+ muzzle brakes. Using high-speed photography and household products, he captured the blast pattern of 20+ different brake designs for easy side-by-side comparison. Can you figure out how Cal managed to show muzzle brake blasts so clearly? His “hi-viz” solution, revealed in the article, is very clever. See the eye-opening results for 20+ brakes, with illustrative photos, by visiting the Precision Rifle Blog Muzzle Brake Ground Signature Test Page.
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Many hunters and precision rifle competitors use muzzle brakes because these ported devices reduce felt recoil significantly. That makes a real difference getting back on target for quick follow-up shots. While many rifle owners appreciate the benefits of muzzle brakes, they may also neglect their brakes, allowing hard carbon and powder residue to build up. Not good. You should regularly clean your muzzle brake to remove fouling and carbon build-up.
As Mark Edgreen posted: “Carbon build up on the crown and in the brake is a recipe for poor accuracy.” And another gunsmith reported that customers complained about guns that “shot out way too early” but they only needed to have the brakes cleaned.
Gunsmith and PRS/NRL competitor Jim See recently reminded his Facebook Fans about the importance of cleaning muzzle brakes: “How many times do I have to say it? You need to maintain your rifles. Clean your muzzle brakes people!”. Jim, who runs Elite Accuracy LLC, notes that hard carbon build-up in brakes can definitely harm accuracy. Look at this example:
Muzzle Brake Cleaning Methods
There are various methods for cleaning a brake, we list a variety of techniques, but we would start with NON-corrosive ultrasound. You’ll want to remove the muzzle device before doing these tasks.
1. Use Ultrasonic Cleaning Machine with cleaning solution. This may be the most efficient method: “I place my brake in the ultrasonic cleaner. Shiney as new.” (Jim Moseley).
2. Spray with commercial Carb Cleaner and brush. Then apply anti-corrosion coating.
3. Soak in half hydrogen peroxide and half vinegar. Suggestion: “Let sit over night and carbon melts off. Brush remaining carbon off, rinse and put the brake back on.” Apply anti-corrosive before mounting.
4. Soak in 50/50 solution of water and white vinegar and brush. (Be sure to apply anti-corrosion coating, such as Eezox, after soaking).
5. Tumble in liquid solution with stainless pins. Comment: “Comes out slightly faded, but perfectly clean on stainless, non-painted brakes though.” Warning — do NOT do this with threaded brakes — tumbling could affect threads of screw-on brakes. Also, tumbling can harm painted or Cerakote finishes.
Gunsmithing Tip: By fitting the muzzle brake so that the barrel crown is slightly forward, it is easier to wipe carbon fouling off the end of the barrel. See photo:
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GunsAmerica Digest has a new Suppressor Academy webpage that provides host of helpful information about suppressors (aka “silencers” and “cans”). The Suppressor Academy online resource page features in-depth articles with important information for anyone considering acquiring a suppressor. The articles explain the key benefits of suppressors, how to choose a suppressor, and how to comply with Federal and state laws regulating suppressors. Below we link to four Suppressor Academy articles. Click the title for each topic to read the full-length article.
Suppressors are now legal in 42 U.S. States. There are certain legal requirements for obtaining a suppressor, including paying a $200 Tax Stamp. To own a suppressor you must be legally eligible to purchase a firearm, pass a BATFE background check, pay a one time $200 Transfer Tax, and satisfy age requirements. (SEE ALL Requirements). In most (but not all) of those states you can use a suppressor for hunting. The eight (mostly blue) states which still prohibit civilian suppressor ownership are: California, Delaware, Hawaii, Illinois, Massachusetts, New Jersey, New York, and Rhode Island. READ FULL ARTICLE on GunsAmerica Digest.
Suppressors serve one main purposes — to reduce the sound levels produced when firing pistol or rifle rounds. But GunsAmerica Digest editor True Pearce notes there are many other reasons to own a suppressor. A suppressor can reduce muzzle blast and felt recoil. The suppressor may prevent hearing damage that occurs through bone conduction better than earplugs and muffs because it reduces the noise energy at the source. When hunting, the reduced shot noise can help avoid spooking game. Having a suppressor also makes it easier to communicate when working as a team on a hunt. And, when compared to a muzzle BRAKE, suppressors are much less likely to kick up dust, dirt, sand, and snow when you shoot prone. READ FULL ARTICLE on GunsAmerica Digest.
There is some confusion surrounding the laws concerning suppressors, which are now legal in 42 U.S. States. In most jurisdictions that allow suppressor ownership, no additional state permit or license is required. But you do have to comply with Federal requirements when acquiring the suppressor. You may wish to create a trust to own the suppressor — there are some important practical advantages to having a suppressor trust. The Traditional NFA Gun Trust allows multiple responsible parties, i.e. “trustees”, to legally have possession of the suppressor. Each trustee must be verified and for each suppressor owned by the trust there will be a $200 Tax Stamp. READ FULL ARTICLE on GunsAmerica Digest.
When shopping for a suppressor there are many factors to consider: price, build quality, materials, sound level reduction effectiveness, weight, ease of mounting, and ease of cleaning and maintenance. We recommend that all suppressor buyers research the options. Check the manufacturer’s reputation, check diagrams for disassembly and maintenance. There are always trade-offs. Shorter suppressors may save some weight, but if they don’t cut the decibels as well you may be disappointed. You also need to consider the caliber — will your suppressor be used on multiple firearms? If so then get one that fits the largest caliber you will shoot. READ FULL ARTICLE on GunsAmerica Digest.
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A while back, Cal Zant at PrecisionRifleBlog.com did a big muzzle brake comparison test. Along with measuring recoil reduction, Cal’s team recorded sound levels in PRB’s exhaustive muzzle brake field test. In the PRB archives you’ll find comprehensive muzzle brake sound test results, with hard data on 20 different muzzle brakes.
Sound can be a tricky subject, but Cal Zant, the editor of PrecisionRifleBlog.com, presents everything an informed shooter should know about muzzle brake noise in a straightforward and practical way. Most sound tests are measured from the side of the muzzle, in accordance with mil-spec standards, and Cal did that. But he also measured the sound level of each brake from behind the rifle, closer to the shooter’s position. This provides a more accurate indicator of the actual sound levels that firearms operators will encounter while shooting their rifles.
Muzzle brakes ARE really loud — that’s something most active shooters have observed. But this study finally gives us some hard data and makes objective comparisons. The difference between brakes was quite significant. Some brakes were ear-splitting — more than twice as loud as other brakes tested.
As a bonus, Cal also provides data on how the new Ultra series suppressors from Thunder Beast Arms Corp (TBAC) compare in terms of sound level behind the rifle.
A while back, the Precision Rifle Blog conducted a fascinating study of Muzzle Brakes. PRB figured out a way to show the actual “blast pattern” of gasses ejecting from the ports of muzzle brakes. The result was a fascinating (and eye-catching) series of images revealing the distinctive gas outflows of 20+ different types of muzzle brakes. If you are considering buying and installing a muzzle brake on your rifle, you should definitely review this important PRB Muzzle Brake Test.
For a prone shooter, particularly on dusty, dirty or sandy ground, muzzle blast is a major bummer. Muzzle blast can be very disturbing — not just for the trigger-puller but for persons on either side of the gun as well. Some muzzle brakes send a huge shockwave back towards the shooter, and others send blast towards the ground, kicking dirt and debris into the prone shooter’s face. If there was a way to illustrate those factors — shockwave and debris — that might help shooters select one brake design over another.
Cal Zant at PrecisionRifleBlog.com applied a unique blend of creativity and resourcefulness to try to answer that question for 20+ muzzle brakes. Using high-speed photography and household products, he captured the blast pattern of 20+ different brake designs for easy side-by-side comparison. Can you figure out how Cal managed to show muzzle brake blasts so clearly? His “hi-viz” solution, revealed in the article, is very clever. See the eye-opening results for 20+ brakes, with illustrative photos, by visiting the Precision Rifle Blog Muzzle Brake Ground Signature Test Page.
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Here is beautiful F-Open rig crafted by Forum member CigarCop of KW Precision LLC. It features a laminated wood stock with stunning figured walnut on the outside.
One of the most popular items in our Shooters’ Forum is the ongoing “Pride and Joy” thread. Since 2009, Forum members have posted photos and descriptions of their most prized rifles. Here are some of the most popule “Pride and Joy” rifles showcased in our Forum. Do you have a gun you’d like to see featured there? Just Register for the Forum and you can add your favorite gun to the list. You’ll enjoy the Forum, which recently hit the 70,000-member mark!
600/1000 Benchrest Light Gun for Richard Schatz in 6 BRA
This blue benchrest rig was crafted by Alex Wheeler for ace benchrest competitor Richard Schatz, a past 600-yard IBS Shooter of the Year. Richard’s new 600/1000-yard Light Gun features a Krieger barrel chambered in 6 BRA (40° Ackley version of 6mmBR Norma). That Krieger is mated to a 1.550″ BAT B action, ignition-timed for smooth bolt close and increased accuracy. The trigger is the sophisticated Bix’n Andy. Schatz’s BAT is glued and screwed into a Wheeler LRB stock, with aluminum rails and adjustable metal “tracking rudder” on the toe of the stock. The rudder can be adjusted side to side to ensure optimal tracking, while the rudder’s vertical angle can be adjusted slightly with shims.
Hand-Crafted Thumbhole-Stocked Rifle Chambered in 6 PPC
Forum Member Grimstod offered this handsome 6 PPC custom with a beautiful, hand-made thumbhole stock: “This was fully accurized with Premier Accuracy recoil lug installed. Really makes these shoot a lot better. It features a Kelbly Panda action with Hart barrel and glass bedding. Trigger fall was perfect to start and we have to give Ian Kelbly big thumbs up for making every action perfectly timed.” On top is a March competition scope. See more photos at www.premieraccuracy.com.
A Wicked Accurate Big Dawg in 28 Nosler
This 28 Nosler Benchrest rifle looks good and shoots even better — check out that 20-shot target shot at 200 yards! You can’t argue with that…
Belonging to Forum member LA50Shooter, this rig is chambered in 28 Nosler, with metal work by Gre-Tan Rifles. The action is a BAT Model “L” 1.650 Octagon with a 30 MOA scope rail, running a Jewell BR Trigger. The stock, from D&B Supply, is a Shehane Big Dawg Tracker with 5″ fore-end. Color scheme is “Field & Stream” Rutland laminate. This big rig boasts FOUR 34″ Benchmark barrels (1.5″ for seven inches tapering to 1.225″ at muzzle).
A Pair of Score Benchrest Beauties
Forum member JimPag showcased two new Benchrest-for-Score rifles. The rig on the left, smithed by Dwight Scott, features a Farley Black Widow RBLPRE (with Bix’n Andy trigger). It features Pistachio and Carbon Terry Leonard stock glued and screwed by Sid Goodling. The barrel is a Krieger 23.5″ chambered in 30BR with a Mike Ezell tuner. It’s topped with a Goodling-built 1-piece Davidson base and a Nightforce 42X Comp scope. The rifle on the right, smithed by Sid Goodling, features a Marsh Saguaro RBLPRE Action with Bix’n Andy trigger, and March 36-55X scope. This rifle boasts a rare Screwbean Mesquite and carbon stock by Terry Leonard. The 23″ Lilja bbl is chambered in 30 Thrasher with a Goodling tuner. (30 Thrasher is longer 30 BR case developed by Joe Entrekin). Jim also has two other barrels for this action in 30 BR and 6 BRAI. On top is a Sid Goodling-built one-piece Davidson base with a March 36-55X scope.
6BRA with BAT Action, Brux Barrel — The Blue Beauty
Next is a blue 6BRA beauty from Forum Member RiflePainter: “This is my brand new 6BRA Light Gun built by Jason Danley at Danley Precision! Jason did all of the work including paint. Brass was done by Darrel Jones at DJ’s brass service.” This features a Johnny Byers stock painted in HOK Custom Oriental Blue Candy mix. The action is a BAT DS Left-load, Right-eject, Right bolt fitted to a 1.5 oz. Jewell trigger. The barrel is a 28″ Brux HV 1:8″-twist chambered for the 6BRA (6mmBR Ackley) and fitted with a Harrell’s radial muzzle brake. On top is a Sightron SIII 10-50x60mm optic riding in BAT 1-piece scope rings.
Rem 700 in Manners Stock — .284 Winchester for Hunting
Here’s a Rem 700 enhanced with a Manners Elite TA stock and other upgrades. Forum Member NickB1075 says: “Here is a rifle I finished for hunting this year. It’s a bit heavy for New York woods carry but it just shoots great. Maybe I will have to get one of those fancy Proof Research barrels to lighten it up a bit.” Nick is running a Benchmark 1:8.5″-twist barrel chambered in .284 Win with 0.315 neck for shooting 150gr Barnes bullets. Nick added a Jewell trigger and on top is a U.S. Optics B10 Scope.
When Only the Biggest and Boldest Will Do — .50 BMG
No “Pride and Joy” feature would be complete without a Big Boomer. This impressive .50 BMG, “61 inches of big bore goodness”, weighs a whopping 49 pounds (95 lbs. complete with case and accessories). This rifle’s proud owner, forum member 6MT, says everything on this black beast is jumbo-sized: “Yes, I can stick my finger clear through the ports in the muzzle brake!” The rifle boasts a U.S. Ordnance 31″ heavy-contour barrel fitted to Barnard GP action. The stock is a “Big Mac” from McMillan. No optics yet — 6MT says he is “looking at an ATACR 7-35x56mm with a Spuhr mount… As soon as my wallet recovers!”
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Many hunters and precision rifle competitors use muzzle brakes because these ported devices reduce felt recoil significantly. That makes a real difference getting back on target for quick follow-up shots. While many rifle owners appreciate the benefits of muzzle brakes, they may also neglect their brakes, allowing hard carbon and powder residue to build up. Not good. You should regularly clean your muzzle brake to remove fouling and carbon build-up.
As Mark Edgreen posted: “Carbon build up on the crown and in the brake is a recipe for poor accuracy.” And another gunsmith reported that customers complained about guns that “shot out way too early” but they only needed to have the brakes cleaned.
Gunsmith and PRS/NRL competitor Jim See recently reminded his Facebook Fans about the importance of cleaning muzzle brakes: “How many times do I have to say it? You need to maintain your rifles. Clean your muzzle brakes people!”. Jim, who runs Elite Accuracy LLC, notes that hard carbon build-up in brakes can definitely harm accuracy. Look at this example:
Muzzle Brake Cleaning Methods
There are various methods for cleaning a brake, we list a variety of techniques, but we would start with NON-corrosive ultrasound. You’ll want to remove the muzzle device before doing these tasks.
1. Use Ultrasonic Cleaning Machine with cleaning solution. This may be the most efficient method: “I place my brake in the ultrasonic cleaner. Shiney as new.” (Jim Moseley).
2. Spray with commercial Carb Cleaner and brush. Then apply anti-corrosion coating.
3. Soak in half hydrogen peroxide and half vinegar. Suggestion: “Let sit over night and carbon melts off. Brush remaining carbon off, rinse and put the brake back on.” Apply anti-corrosive before mounting.
4. Soak in 50/50 solution of water and white vinegar and brush. (Be sure to apply anti-corrosion coating, such as Eezox, after soaking).
5. Tumble in liquid solution with stainless pins. Comment: “Comes out slightly faded, but perfectly clean on stainless, non-painted brakes though.” Warning — do NOT do this with threaded brakes — tumbling could affect threads of screw-on brakes. Also, tumbling can harm painted or Cerakote finishes.
Gunsmithing Tip: By fitting the muzzle brake so that the barrel crown is slightly forward, it is easier to wipe carbon fouling off the end of the barrel. See photo:
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A while back, the Precision Rifle Blog conducted a fascinating study of Muzzle Brakes. PRB figured out a way to show the actual “blast pattern” of gasses ejecting from the ports of muzzle brakes. The result was a fascinating (and eye-catching) series of images revealing the distinctive gas outflows of 20+ different types of muzzle brakes. If you are considering buying and installing a muzzle brake on your rifle, you should definitely review this important PRB Muzzle Brake Test.
For a prone shooter, particularly on dusty, dirty or sandy ground, muzzle blast is a major bummer. Muzzle blast can be very disturbing — not just for the trigger-puller but for persons on either side of the gun as well. Some muzzle brakes send a huge shockwave back towards the shooter, and others send blast towards the ground, kicking dirt and debris into the prone shooter’s face. If there was a way to illustrate those factors — shockwave and debris — that might help shooters select one brake design over another.
Cal Zant at PrecisionRifleBlog.com applied a unique blend of creativity and resourcefulness to try to answer that question for 20+ muzzle brakes. Using high-speed photography and household products, he captured the blast pattern of 20+ different brake designs for easy side-by-side comparison. Can you figure out how Cal managed to show muzzle brake blasts so clearly? His “hi-viz” solution, revealed in the article, is very clever. See the eye-opening results for 20+ brakes, with illustrative photos, by visiting the Precision Rifle Blog Muzzle Brake Ground Signature Test Page.
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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.
NOTE: This is a copyrighted article. Do not reproduce or re-link more than 75 words without written permission from AccurateShooter.com.
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Many hunters and precision rifle competitors use muzzle brakes because these ported devices reduce felt recoil significantly. That make s real difference getting back on target for quick follow-up shots. While many rifle owners appreciate the benefits of muzzle brakes, they may also neglect their brakes, allowing hard carbon and powder residue to build up. Not good. You should regularly clean your muzzle brake to remove fouling and carbon build-up.
As Mark Edgreen posted: “Carbon build up on the crown and in the brake is a recipe for poor accuracy.” And another gunsmith reported that customers complained about guns that “shot out way too early” but they only needed to have the brakes cleaned.
Gunsmith and PRS/NRL competitor Jim See recently reminded his Facebook Fans about the importance of cleaning muzzle brakes: “How many times do I have to say it? You need to maintain your rifles. Clean your muzzle brakes people!”. Jim, who runs Elite Accuracy LLC, notes that hard carbon build-up in brakes can definitely harm accuracy. Look at this example:
Muzzle Brake Cleaning Methods
There are various methods for cleaning a brake, we list a variety of techniques, but we would start with NON-corrosive ultrasound. You’ll want to remove the muzzle device before doing these tasks.
1. Use Ultrasonic Cleaning Machine with cleaning solution. This may be the most efficient method: “I place my brake in the ultrasonic cleaner. Shiney as new.” (Jim Moseley).
2. Spray with commercial Carb Cleaner and brush. Then apply anti-corrosion coating.
3. Soak in half hydrogen peroxide and half vinegar. Suggestion: “Let sit over night and carbon melts off. Brush remaining carbon off, rinse and put the brake back on.” Apply anti-corrosive before mounting.
4. Soak in 50/50 solution of water and white vinegar and brush. (Be sure to apply anti-corrosion coating, such as Eezox, after soaking).
5. Tumble in liquid solution with stainless pins. Comment: “Comes out slightly faded, but perfectly clean on stainless, non-painted brakes though.” Warning — do NOT do this with threaded brakes — tumbling could affect threads of screw-on brakes. Also, tumbling can harm painted or Cerakote finishes.
Gunsmithing Tip: By fitting the muzzle brake so that the barrel crown is slightly forward, it is easier to wipe carbon fouling off the end of the barrel. See photo:
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While a 16.5-pound benchrest gun is wonderfully stable on the bench, it’s not what you want in a field rifle. There is much to be said for a slim, light-weight, and easy-handling firearm when it comes to a walking varmint adventure. Eben Brown, who runs E. Arthur Brown Company, has created just such a rifle — the Model 97D Falling Block. When chambered for the 6PPC cartridge it delivered quarter-MOA accuracy in a splendidly portable package that tips the scales at just over six pounds without scope. The Model 97D is fairly unique in its lightweight and compact format — that makes it a great field-carry varmint rig. [Editor’s Note: This is an older article and we use some more recent photos of other model 97D Rifles to better illustrate the design and layout.]
Catalog photo of EABCO Model 97D Falling Block rifle.
Excellent Accuracy Made Easy for Sport Shooters
by Eben Brown, E. Arthur Brown Company
You don’t have to be a benchrest competitor to enjoy shooting one of the most accurate centerfire cartridges in the world, the 6mm PPC. With no complicated brass forming or finicky reloading processes, you can be shooting near half-inch groups right from the start and hone your skills to near quarter-inch groups by your second outing–at least that’s how it worked for me, and I’m NOT a good bench rest shooter! Developed by Louis Palmisano and Ferris Pindell, the 6PPC has won more bench rest accuracy competitions than any other cartridge. Easily made from Lapua .220 Russian brass, the 6mm PPC has a small primer and uniquely small flash hole that is credited for much of its inherent accuracy. The “short, fat” shape and nearly straight body contribute to efficient, consistent powder burning and stable chamber performance (it grips the chamber well during ignition).
The Brown Model 97D — A Slim, Accurate 6-Pound Rifle
The 97D was developed from the EABCO “BF” falling block silhouette pistols that have won world championships and set 500-meter distance records. In operation, the 97D falling block slides perpendicularly and closes the breech with absolutely zero camming leverage. This makes it a perfect test-bed to measure the chamber performance needed for hand-loading most other single-shot rifles accurately. At the reloading bench, I worked up a load with the now fully shaped 6mm PPC brass. I full-length sized the brass, trimmed, and primed each case the same as I would with any other cartridge, and began loading. With the resultant load, I easily shot a 5-shot 1/4″ group, a personal best for me. See target photo at right.
Making 6mm PPC Cartridges
Full-length size, prime, charge with powder, and seat a bullet… sounds like what you do with any other cartridge, doesn’t it? In fact, the only difference with 6mm PPC is that it has to be fired once (fire-formed) to expand to its final shape and size. But even fire-forming shots produce exceptional accuracy. I shot several 3/4″ groups while fire-forming at 100 yards, with my best group at nearly half-inch–so the time spent fire-forming was wonderful! In the photo, the parent .220 Russian case is on the left, while the fire-formed 6PPC case is on the right.
The EABCO 6mm PPC Chamber – 6PPC without Neck-turning!
We dimensioned our 6mm PPC chamber reamer to cut a chamber that fits Lapua 220 Russian brass closely without neck-turning. Naturally we recommend you use the Lapua brass for best results.
[Editor’s Note: We asked Eben if he had tried a 6BR chambering in a model 97D. He explained that, because of the extractor design, the falling block action works better with a smaller rim diameter: “The larger .308 rim width creates some issues. This design works best with cartridges no wider than the 30/30 case, or the 7.62×39 case, from which the 22 Russian case was derived. Cases with .308-sized rims develop more bolt thrust and work best with a different type of extractor than we use in the 97D. I love the 6BR, but I recommend the 6PPC for our 97D.”]
6mm PPC Reloading Data for Model 97D
The following loads were worked up in a Model 97D Rifle with 24″ barrel chambered for 6mm PPC with the chamber neck reamed to .275″ to fit Lapua brass without neck-turning. Lapua 220 Russian brass was full-length sized and fire-formed to 6mm PPC using 65gr V-Max bullets, CCI BR4 primers, and 24.5gr of VV N135 powder. Eben cautions: Load at Your Own Risk — Always start 10% low and work up
The following optimum loads were worked up with Vihtavuori N135, 58gr and 65gr V-Max bullets, and CCI BR4 primers. Please Note: There really is no “standard” for 6mm PPC. It can be finicky. But once you find what works best for you, the cartridge performs superbly. The accuracy will astound you.
Model 97D Specifications
OAL (with 24″ Barrel): 38″
Approx. Weight without Scope: 6-6.5 lbs.
Barrel: 17-26″ Chromoly or Stainless
Stock: Walnut w/Hardwood Grip Cap
Trigger: Tuned 16-24 ounces
This video shows the Loading Technique for Model 97D Rifle
Powder Selection — Choosing the Right Propellant
I’ve found that my maximum single-shot loads reach the same level of performance as bolt gun loads when I use one level slower burning powder type and proper chamber preparation. For example, when the VihtaVuori loading guide shows a maximum with VV N133, my best single shot load ends up being with the slower burning VV N135. Here’s the simplest way to proceed: Use a starting load from the loading guide and increase the powder charge until you detect some resistance to block movement with your thumb. Next, charge a case with that same amount of powder, tap it to settle, and look to see if the case is full to the base of the neck. If it’s not full, step up to the next slower-rated powder and repeat the load development process. There’s a powder burn rate chart for all brands of powder in the front of the current VihtaVuori Loading Guide. When you have the maximum load that will fill the case and still allow the 97D single-shot to open and eject freely after firing, you’re ready to shoot some groups!
Loading for Best Chamber Performance
In the model 97D rifle you can check chamber performance easily. After firing a shot, see if you can press the block downward with only your thumb on the top of the block. If it moves freely, you’ve got good chamber performance.
I use three pressure indicators when developing loads on the Model 97D. First I check the block with my thumb. Then I check to see if the cartridge sticks at all when ejecting. And finally, I check the primer for the excessive flattening that would indicate too much pressure. Generally, the hottest load that still allows the gun to open and eject freely ends up being my most accurate shooting load.
Chamber Preparation
Best chamber performance happens when a cartridge grips the chamber and does not drive backward significantly. When you want something to grip (rather than slip), you want to make sure there is no lubricant on the gripping surfaces. Case forming lube and gun oil are the two lubricants you want to remove. Clean your 6mm PPC cases after sizing (I wipe mine with a paper towel and Windex). Clean your chamber with a chamber sized jag and patch wetted with acetone. (Note: protect your chamber with a thin coat of Clenzoil when you’re not out shooting.)
Conclusions of a Single-Shot Sport Shooter
I love the 6mm PPC! It was easy to hand-load for the cartridge and it was easy to get excellent results. The group shot on this page was with the 65gr bullet and a rifling twist of 1:10. I usually recommend a 1:12 twist and the 58gr bullet because customers have reported superb accuracy (better groups than I can shoot). But the 5-shot ¼” group I shot with this set-up is my personal best ever–so naturally I’m thrilled!
While it’s hard to beat the 6PPC’s accuracy in a Model 97D rifle, my company currently offers the rifle in a variety of chamberings including 17 Hornet, 219 Donaldson Wasp, and 6mm BRM. The 97D Standard features a blued 24″ chrome-moly barrel, French Gray receiver, anodized buttstock transition, 2-ring scope mount and swivel studs.– Eben Brown
About the production Model 97D Rifles: “The 97D is a small frame single shot rifle that’s suitable for big game as well as small game and varmint hunting. It originally evolved from our World Champion long range silhouette pistol action and incorporates the same accurate gun making processes. The 97D action itself is inherently accurate and simple. Onto this we fit an EABCO Accuracy Barrel, precision turned and threaded between centers. Each chamber is individually reamed on-center and individually head spaced. We feel the crown is so critical to accuracy that we leave it until after the gun is finished. Our 11 degree target crowns are cut last and left bright — our trademark finishing touch.”
The Brown Model 97D — A Slim, Accurate 6-Pound Rifle
Making 6mm PPC Cartridges
The EABCO 6mm PPC Chamber
The following optimum loads were worked up with Vihtavuori N135, 58gr and 65gr V-Max bullets, and CCI BR4 primers. Please Note: There really is no “standard” for 6mm PPC. It can be finicky. But once you find what works best for you, the cartridge performs superbly. The accuracy will astound you.
Loading for Best Chamber Performance
