Here’s an interesting $75 product that can help you “tune” the cycling force of your AR-platform rifle. Wilson Combat offers an Adjustable Lo-Profile AR Gas Block for direct gas impingement AR-type rifles. Wilson Combat’s adjustable gas block replaces a standard AR gas block and allows you to tune your AR’s gas system for smoother cycling and enhanced reliability. Wilson Combat explains: “Adjusting your rifle’s gas port will lower or increase your bolt’s cyclic rate. This tailors your rifle’s performance to your unique needs.” When varmint hunting with an AR, we like a less-energetic ejection so the brass lands close to the gun (and doesn’t tag fellow shooters).
A simple adjustment of the hex screw at the front of the block modulates the gas volume allowing you to tune your rifle’s function to your favorite loads. This is very handy when shooting non-standard AR calibers, unusual hand-loads, or suppressed rifles. Adjustable Gas Block systems are sold as complete kits starting at $74.95. Wilson Combat offers two diameters (.750″, .937″) and three lengths (Carbine Length, Mid-Length, & Rifle Length), so you can select the right dimensions for your rifle configuration and barrel diameter. The blocks are Chromoly steel with a Melonited finish.
Package Includes:
Adjustable Gas Block (Melonite Finish)
Adjustment Set Screw (Installed)
Straight Gas Tube (Installed, Gas Tube Pin Installed)
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.
Gun guys are always shipping stuff around the country — whether it’s a barrel to be chambered, or a scope that needs to go back for warranty repair. Or maybe you’ve sold some bullets or reloading dies you no longer need. To ensure your precious packages get to their destination in one piece, it’s important to take precautions when boxing up your items. And by all means insure packages for full value — even if your packaging is perfect, there is always the possibility that your shipment might be lost altogether. Sadly, that can happen, no matter which carrier you choose: Fedex, UPS, or the U.S. Postal Service (USPS). Here are some tips for shipping gun stuff — we explain how to pack items properly and how to minimize the risk of loss.
Tips for Shippers
Dennis Haffner from McGowen Precision Barrels offers some advice on how to avoid damage when shipping gun parts or other valuable or heavy items. Dennis explains:
“First, I started double-packing the contents and in many cases double-boxing. I spend a fortune on heavy-reinforced shipping tape. If the contents are loosely packed, the package is going to get crushed. On real important items or delicate items, wrap the content in plastic and spray the inside void areas with non-expanding foam. They make shipping foam just for this. This method really works. Since I started paying more attention to packaging, I have just about wiped out my issues with all three companies (Fedex, UPS, USPS). Yes, I hate doing it, but in the long run for us, it’s cheaper.
Bullet shipments are the worst — a shipment of 500+ bullets can destroy a cardboard box. I have ordered bullets from individuals who put them in baggies and filled the remainder of the box with foam peanuts. That is not going to work. Any piece of metal, including a die, will puncture a cardboard box, or destroy a padded envelope. Just look at the tracking information and imagine your package bouncing around in the back of the shipping truck, probably under many other packages. My advice is to NEVER use padded envelopes. Barrel nuts or recoil lugs will most likely never make it.
ORM-D items are required to be shipped in heavily-reinforced, double-walled containers. The packages still get a little damage, but the contents usually survive.
How do shipments get damaged? Consider this — one of the shipping companies this year flipped (overturned) one of our new CNC machines (which rendered it useless). Maybe your small packages were in the same delivery truck as my CNC machine. I wonder how many little boxes were crushed underneath it.
As for USPS flat rate boxes — you would not believe what people try to stuff in these boxes. USPS finally put a weight limit on the boxes — they had to. I sometimes take my delicate items packed in an envelope or small box. I spray foam in a larger flat rate box and insert the smaller package, then fill the remainder of the void with foam. It works, and part usually arrives undamaged.”
Shipping Rifle Barrels (PVC Tube and Tennis Ball Method)
A new match-grade barrel can cost $350 or more, and it might take six months (or more) to replace it, given the current wait time with top barrel-makers. So, you don’t want your nice new tube to get damaged in transit. Forum Member Chuck L. (aka “M-61″) offers these tips for shipping rifle barrels:
“Packing a barrel can be a problem. Here’s a shipping method that won’t stop lost shipments but so far has stopped damage. Get a PVC pipe (of size appropriate to your barrel) with fitted caps for each end. Attach a cap to one end. Tape the barrel threads and tape over the muzzle. Then drop one standard tennis ball into the pipe. Place barrel in pipe. Next add whatever peanuts or foam you can jam in to support the barrel on the sides. Then place a second tennis ball into the opposite end of the PVC pipe. (So now you have a tennis ball on either end of your barrel.) With everything secure inside, attach the upper cap and tape it down securely. With this packing procedure, when the carrier launches the pipe like a javelin, at least the barrel will not come through like a spear and be gone. Label the pipe with very large address labels so no one suspects it’s just garbage laying around. This procedure may seem ridiculous but it has worked for me. Oh and definitely get insurance. If your item is insured, the shippers will look harder to find it.”
Editor’s Note: Fedex also makes a triangular-profile cardboard shipping box. This 38″ x 6″ x 6″ x 6″ Fedex Tube (designed for blueprints and posters) is free for the asking. For most barrels, there should be enough clearance to hold your PVC tube (with barrel packed inside tube). However, don’t ship the barrel inside the cardboard box by itself. Cap and pad the ends and bubble wrap it heavily, or better yet, use the PVC tube method described above, with the PVC tube inside the box.
Ask 10 shooters about barrel cleaning and you’ll get 10 different opinions. This reflects that fact that different fouling problems demand different solutions. For example, solvents that work well for copper may not be the best for hard carbon (and vice-versa). To come up with the right solution, first you must understand the nature of the fouling in your barrel.
The debate about the proper care of a match barrel is a hot one, spiked with folklore and old wives’ tales, Lohman said. He and his staff set out to set the record straight: “We tried to interject some science into the discussion of cleaning a match barrel,” he explained. In his article, Lohman writes:
Why worry about a little barrel fouling when the throat is subjected to a brutal 5,600° F volcano at 55,000 PSI? To investigate these and other questions about taking care of a match barrel, we spoke with a dozen experts and share their knowledge in this first of a series of articles.
After listening to folks who shoot, build barrels or manufacture cleaning solvents for a living, we concluded that even the experts each have their own unique recommendations on how to care for a match barrel. But they all agree on one thing — the gun will tell you what it likes best. Because the life expectancy of a match barrel is about 1,500 to 2,500 rounds, the objectives of cleaning one should include: preserve accuracy, slow the erosion, and remove fouling — all without damaging the gun. This article doesn’t claim that one cleaning method is better than the next. Rather, we set out to interject a little science into the discussion and to share some lessons learned from experts in the field.
For more Shooting Sports USA articles, visit www.ssusa.org.
John Krieger Interview with AccurateShooter at SHOT Show:
Tuners work. So do muzzle brakes. But until recently, you had the choice of one or the other. Now with combo tuner/brakes you can tune the harmonics of your rifle barrel while enjoying significantly reduced recoil (and torque). This is a “Win-Win” for shooters of heavy-recoiling rifles.
Rifle accuracy and precision have come a long way in the past 15 years, particularly for long-range applications. The most recent tool to significantly improve precision is the barrel tuning system. The Rifle Accuracy System (RAS) developed by Precision Rifle Systems, incorporates a precision muzzle brake with the tuner. CLICK HERE for Product INFO.
This system potentially offers meaningful group size reduction through control of barrel harmonics. The RAS tuner/brake system was the subject of a June 2012 Precision Shooting (PS) magazine article, titled “Improved Rifle Accuracy” and was also featured in an article in the November 2012 issue of PS titled “Tuning with Confidence”.
READ MORE about RAS Tuner Tests on .260 AI, .223 Rem, and 22LR rimfire rifles.
Copies of both articles and detailed instructions on RAS installation and tuning can be downloaded from www.bostromgunsmithing.com. Eric Bostrom is the distributor for the RAS.
Forum member Rich DeSimone uses a handy “Stub Gauge” for setting shoulder “bump” and seating depth. The gauge is made from a section of barrel lopped off when the muzzle is crowned. The chambering reamer is run in about 1/4 of the way, enough to capture the neck and shoulder area of the case. Rich then uses his full-length die to “bump” a master case with the ideal amount of headspace for easy feeding and extraction. He takes that case and sets it in this Stub Gauge, and measures from the front of the gauge to the rim. He can then quickly compare any fired case to a his “master” case with optimal headspace. Since the gauge measures off the shoulder datum, this tells him how much to bump his fired brass.
In addition, the Stub Gauge can be used to set bullet seating-depth. Rich has a channel cut transversely on one side of the gauge, exposing the throat area. Since the interior of the gauge is identical to the chamber in his gun, this lets him see where a seated bullet engages the rifling. He can tinker with bullet seating length until he gets just the right amount of land contact on the bullet, confirmed visually. Then he measures the case OAL and sets his seating dies accordingly. This is much handier than using a Stoney Point Tool to measure distance to the lands. As your barrel’s throat wears, you may seat your bullets out further to “chase the lands”, but the gauge provides a constant land engagement point, in the barrel’s “as new” condition. By measuring the difference between the land contact point on the gauge and the actual contact point on your barrel, you can determine throat “migration”.
Berger Twist-Rate Stability Calculator
On the updated Berger Bullets website you’ll find a handy Twist-Rate Stability Calculator that predicts your gyroscopic stability factor (SG) based on mulitiple variables: velocity, bullet length, bullet weight, barrel twist rate, ambient temperature, and altitude. This very cool tool tells you if your chosen bullet will really stabilize in your barrel.
LIVE DEMO BELOW — Just enter values in the data boxes and click “Calculate SG”.
You never want your barrel to get too hot. Accuracy suffers when barrels over-heat, and excessive heat is not good for barrel life. So how do you monitor your barrel’s temperature? You can check if the barrel is “warm to the touch” — but that method is not particularly precise. There is a better way — using temperature-sensitive strips. McMaster.com (a large industrial supply house) offers stick-on temp strips with values from 86° F to 140° F. A pack of ten (10) of these strips (item 59535K13) costs $10.71. So figure it’ll cost you about a buck per barrel for strips. That’s cheap insurance for your precious barrels.
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.
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 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.
You have to love it when a prototype product not only performs well, but actually wins a match. For some time, Criterion Barrels has been working on a match-grade barrel for vintage Lee-Enfield rifles. It looks like they got things right…
Over the Easter weekend the New Zealand Service Rifle Association held its annual national service rifle competition. Coming first in the Classic Bolt Action class was Wellington’s Nicole McKee shooting a Lee-Enfield with a new, prototype Criterion barrel. Nicole’s rifle was built by her husband Duncan, a vintage rifle expert who specializes in accurizing the No. 4 and SMLE actions. Nicole’s .303 British handloads featured Hornady 174gr FMJ Boattail bullets (SKU: 3131) pushed by 47.0 grains of ADI 2209 (H4350). ADI 2209 has become the top go-to powder for .303 British shooters in New Zealand.
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.
Gun guys are always shipping stuff around the country — whether it’s a barrel to be chambered, or a scope that needs to go back for warranty repair. Or maybe you’ve sold some bullets or reloading dies you no longer need. To ensure your precious packages get to their destination in one piece, it’s important to take precautions when boxing up your items. And by all means insure packages for full value — even if your packaging is perfect, there is always the possibility that your shipment might be lost altogether. Sadly, that can happen, no matter which carrier you choose: Fedex, UPS, or the U.S. Postal Service (USPS). Here are some tips for shipping gun stuff — we explain how to pack items properly and how to minimize the risk of loss.
“First, I started double-packing the contents and in many cases double-boxing. I spend a fortune on heavy-reinforced shipping tape. If the contents are loosely packed, the package is going to get crushed. On real important items or delicate items, wrap the content in plastic and spray the inside void areas with non-expanding foam. They make shipping foam just for this. This method really works. Since I started paying more attention to packaging, I have just about wiped out my issues with all three companies (Fedex, UPS, USPS). Yes, I hate doing it, but in the long run for us, it’s cheaper.
How do shipments get damaged? Consider this — one of the shipping companies this year flipped (overturned) one of our new CNC machines (which rendered it useless). Maybe your small packages were in the same delivery truck as my CNC machine. I wonder how many little boxes were crushed underneath it.
“Packing a barrel can be a problem. Here’s a shipping method that won’t stop lost shipments but so far has stopped damage. Get a PVC pipe (of size appropriate to your barrel) with fitted caps for each end. Attach a cap to one end. Tape the barrel threads and tape over the muzzle. Then drop one standard tennis ball into the pipe. Place barrel in pipe. Next add whatever peanuts or foam you can jam in to support the barrel on the sides. Then place a second tennis ball into the opposite end of the PVC pipe. (So now you have a tennis ball on either end of your barrel.) With everything secure inside, attach the upper cap and tape it down securely. With this packing procedure, when the carrier launches the pipe like a javelin, at least the barrel will not come through like a spear and be gone. Label the pipe with very large address labels so no one suspects it’s just garbage laying around. This procedure may seem ridiculous but it has worked for me. Oh and definitely get insurance. If your item is insured, the shippers will look harder to find it.”
Tuners work. So do muzzle brakes. But until recently, you had the choice of one or the other. Now with combo tuner/brakes you can tune the harmonics of your rifle barrel while enjoying significantly reduced recoil (and torque). This is a “Win-Win” for shooters of heavy-recoiling rifles.
Forum member Rich DeSimone uses a handy “Stub Gauge” for setting shoulder “bump” and seating depth. The gauge is made from a section of barrel lopped off when the muzzle is crowned. The chambering reamer is run in about 1/4 of the way, enough to capture the neck and shoulder area of the case. Rich then uses his full-length die to “bump” a master case with the ideal amount of headspace for easy feeding and extraction. He takes that case and sets it in this Stub Gauge, and measures from the front of the gauge to the rim. He can then quickly compare any fired case to a his “master” case with optimal headspace. Since the gauge measures off the shoulder datum, this tells him how much to bump his fired brass.
