April 12th, 2014
Remington Arms Company, LLC (Remington) is recalling Model 700 and Model Seven rifles with X-Mark Pro® (XMP) triggers, manufactured from May 1, 2006 to April 9, 2014. The reason for the recall is that “Remington engineers determined that some Model 700 and Model Seven rifles with XMP triggers could, under certain circumstances, unintentionally discharge.” READ Recall Notice.
Remington’s investigation determined that some XMP triggers might have excess bonding agent used in the assembly process, which could cause an unintentional discharge. Therefore, Remington is recalling ALL affected products to fully inspect and clean the XMP triggers with a specialized process. Remington has advised customers to immediately cease use of recalled rifles and return them to Remington free of charge. The rifles will be inspected, specialty cleaned, tested, and returned as soon as possible. Remington advises: “Do not attempt to diagnose or repair recalled rifles”.
Remington now offers a dedicated website and toll-free hotline to help consumers determine whether their Model 700 or Model Seven rifle(s) are subject to recall.
- Remington Recall Website: http://xmprecall.remington.com
On this website you can enter rifle serial number(s) to determine, in seconds, if a particular rifle is subject to recall.
- Toll-Free Recall Hotline: 1-800-243-9700
(Prompt #3 then Prompt #1) Monday through Friday, 9 am to 5 pm EDT.
The Remington Recall Notice also says that a visual inspection can reveal if a rifle is subject to recall. You may determine if your rifle is subject to the recall by visually inspecting the face of the trigger.
1) If the face of the trigger is ribbed (see Photo (1) below), your rifle does not have an XMP trigger and is NOT subject to this recall.
2) If the face of the trigger is smooth (see Photo (2) below), your rifle has an XMP trigger and IS subject to this recall. You should immediately seek further assistance by calling 1-800-243-9700 or visiting XMPrecall.remington.com.
If You Have A Rifle Subject to Recall
STOP USING YOUR RIFLE. Any unintended discharge has the potential to cause injury or death. Immediately cease use of recalled rifles and return them to Remington free of charge. Rifles will be inspected, specialty cleaned, tested, and returned as soon as possible, at no cost to you. DO NOT attempt to diagnose or repair recalled rifles.
“Remington takes safety extremely seriously,” said Teddy Novin, Director of Public Affairs and Communications. “While we have the utmost confidence in the design of the XMP trigger, we are undertaking this recall in the interest of customer safety, to remove any potential excess bonding agent applied in the assembly process. We have established significant safety and technical resources to determine which rifles are affected and to minimize any risks. Our goal is to have every recalled firearm inspected, specialty cleaned, tested and returned as soon as possible.”
If you have a Model 700 or Model Seven rifle subject to recall, contact Remington right away. Provide the rifle’s serial number and your addresss. Remington will send you pre-paid shipping tags, boxes and written instructions. Remington will cover all related shipping, inspection, and cleaning charges.
Story Tip from EdLongrange. We welcome reader submissions.
Share the post "Remington Recalls Model 700 and Model Seven Rifles with X-Mark Pro Triggers"
April 11th, 2014
This Article Originally Appeared in Sinclair International’s The Reloading Press.
Pre-Season Gun Maintenance,
by Ron Dague, Sinclair International
I give my rifles a pre-season check before the shooting season starts. This starts with a general inspection starting with the butt-plate or recoil pad and making sure that all the screws and adjustable parts (on an adjustable butt-plate) move freely up or down and side to side. If you got caught in rain some of these screws and adjustable parts may not move when needed. I disassemble parts as needed and put rust preventative or a light oil and/or grease on threads and sliding parts. On rifles with recoil pads and fixed butt-plates, make sure the screws are tight and that holes in the stock aren’t stripped out. Make sure there are no cracks in the stock and around the butt-plate. If the recoil pad is glued-on, just make sure it hasn’t come loose.
Next I take the action out of the stock and check for cracks and wear marks. I look at the bedding to make sure that oils and cleaning solvents have not damaged the bedding. While the action is out of the stock, I look for any surface rust or dirt/dust in the recoil lug area and magazine well. Clean as needed and repair or re-bed if needed.
Trigger Assembly and Action
With the barreled action out of the stock, it is a good time to spray out the trigger with cleaner. I use Ronson oil or lighter fluid. [Editor's Note: Some trigger-makers advise against using any kind of lubricant, grease or oil -- so plain lighter fluid is preferred.] After the trigger is cleaned you may want to check the trigger pull weight. If you don’t feel comfortable doing this, take it to a gun smith and have it checked. It is worth every penny to not have a trigger issue and/or a safety malfunction. I also take the bolt apart and clean the firing pin spring and bolt housing with Gun Scrubber or automotive brake cleaner. Then lube the firing pin-spring and firing pin with light oil. I use Kel Lube and/or Butch’s gun oil. Put a small dab of gun grease on the [bolt locking lugs] and cocking ramp.
I will also spray the outside of the action and barrel and give that a light coating of oil for rust prevention. I clean the action with Sinclair’s action cleaning tool. Don’t forget to clean the bore. Even though you didn’t fire the rifle, this makes sure nothing obstructs your barrel.
Checking Metal Fixtures and Fasteners
Next I look at the trigger guard and hinged floor plate and make sure it works as designed. Make sure there are no cracks in the trigger guard from an accidental drop. Check guard screws and /or action screws for tightness and tighten to proper spec. There are torque specs for this, but on wood stocks the wood can crush and this should be checked throughout the year as weather change can affect this. My entire collection of rifles are bedded and I just tighten them just snug with screw driver or Allen wrench. The rimfire rifles have a spec of 55 to 74 inch/lbs and I think would carry over to center fire as well. I would caution you about torque wrenches as you need a good quality wrench, and read the directions on how to use it. You can over torque if not careful. Check the swivel studs and bipod to make sure there tight as well. You may want to take scope off and check the base screws and check the rings.
Test Fire the Rifle After Maintenance
After all cleaning and is done and everything is reassembled, take a few rounds out to the range and test fire to make sure everything works as it should. Don’t forget to run 3-5 rounds through the magazine at least two times for function. I look at this as preventive maintenance on the rifle. If you give it a look over you shouldn’t have any trouble during the rifle matches or hunting trip.
Certified Reloading Instructor
Certified Range Safety Officer
Email: rond [at] sinclairintl.com
Share the post "Pre-Season Maintenance On Your Rifles"
April 6th, 2014
by Bill Gravatt
(This article was written when Bill was President of Sinclair International, Inc.)
Chamber casting is an easy task for the handloader to perform. A chamber casting is valuable if you run across a firearm that you believe has a custom barrel on it and you want to find out the dimensions of the chamber. Some gunsmiths will chamber a barrel and not mark it properly with the neck dimension or the exact cartridge name or specifications. We also get calls from some customers that have military firearms without cartridge stampings on the barrel; this will help these shooters identify their chambering.
Another reason to make a chamber casting would be for a die manufacturer to manufacture custom dies for you. A chamber casting is often required when fired cases are not available. Some reloaders will make a chamber casting that shows them the exact configuration of the throat and leade so they can determine what bullets to try. Shooters using cast bullets will make a cast so they can choose a mould that better fits their throat taper and grove/lands diameter.
A product called Cerrosafe is the most common, reliable, and the safest material to use for making chamber castings. Cerrosafe is a metal alloy that has some unique properties which make it ideal for chamber casting. First, it has a relatively low melting point of 158 to 190° Fahrenheit. This makes it easy for the handloader to melt the Cerrosafe in his home shop. Second, it shrinks slightly during cooling which allows it to be extracted from the chamber easily. It then re-expands to the chamber’s original size after about one hour at room temperature. After cooling for about 200 hours, the chamber cast will expand to about .0025″ larger than the actual chamber size. Most good reloading die makers are used to working from Cerrosafe chamber casts.
As we said, using Cerrosafe is fairly easy and comes with complete instructions.
This article originally appeared in Sinclair International’s The Reloading Press Blog.
Making a Cerrosafe Chamber Cast — Step by Step:
1. First, clean and dry the chamber and barrel thoroughly.
2. Disassemble the firearm as necessary to gain access to the chamber.
3. Insert a tight fitting cleaning patch with a jag into the bore from the muzzle end to form a plug for the Cerrosafe. The patch should be positioned in the bore, just forward of the throat by approximately ½” to 1”.
4. Heat a Cerrosafe ingot in a small ladle. A heavy cast iron bullet caster’s ladle works fine or a plumber’s ladle. Any source of heat will do (a small propane torch will work fine).
5. Pour the Cerrosafe into the chamber until a little mound forms at the rear of the chamber. Too much and it can become more difficult to remove the cast from the chamber. If this happens, simply heat the barrel a little and re-melt the Cerrosafe. Don’t worry, your barrel gets a bit hotter than 190 degrees during firing.
6. The chamber can be difficult to access, so some people find it easier if they make a pouring tube out of steel, brass, or aluminum tubing to funnel the Cerrosafe into the chamber.
7. After the Cerrosafe has hardened, the chamber casting can be pushed out of the chamber coming from the muzzle end using a cleaning rod or a wooden dowel. It is recommended that you push it out within a half-hour of casting the chamber. We usually push our cast out within a few minutes. If the cast does not push out easily, insert a cleaning rod from the muzzle and tap the rod handle with the palm of your hand to start the cast out of the chamber. You can put a paper towel in the action to catch the cast or lay the rifle on the bench with a towel or bench mat underneath it to catch the cast as it falls from the action. This will prevent damage to the cast.
8. Take your measurements shortly after one hour of cast, and then put the casting away until you need it again. A medicine container or something similar makes a great container. If you are going to keep the cast be sure to mark the cast or the storage container so you know which rifle it came from. If you have no need to keep the cast you can re-melt the Cerrosafe and use it again when you need to make another cast.
Share the post "Tech Tip: How to Cast your Chamber using Cerrosafe"
March 27th, 2014
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 $11.86. So figure it’ll cost you about a buck per barrel for strips. That’s cheap insurance for your precious barrels.
Forum member Nomad47 says: “I have temperature strips (bought at McMaster-Carr) on all my barrels. I try not to shoot when the barrel gets to 122 degrees or higher[.]” Here are photos of the McMaster-Carr temp strips on Nomad47′s customized Savage. (This rifle is currently for sale in our Forum Marketplace. It has two Criterion barrels: 6XC, .243 AI.)
Bad things can happen if your barrel gets too hot. First, with some barrels, the point of impact (POI) will shift or “walk” as the barrel heats up excessively. Second, even if the POI doesn’t change, the groups can open up dramatically when the barrel gets too hot. Third, if the barrel is very hot, the chamber will transfer heat to your loaded cartridge, which can lead to pressure issues. Finally, there’s considerable evidence that hot barrels wear out faster. This is a very real concern, particularly for varmint shooters who may shoot hundreds of rounds in a day. For this reason, many varminters switch among various guns, never letting a particular barrel get too hot.
Neconos.com offers Bar-L Benchrest strips that visually display heat readings from 86 to 140 degrees. Think of these strips as compact, unbreakable thermometers. With adhesive backing, they can also be used to monitor barrel heating. Put a strip on the side of the barrel and the barrel’s temp will be indicated by a stripe that changes from black to green. There is also a “general purpose” strip that reads to 196 degrees (bottom row). The Benchrest strip (86F to 140F) is in the middle. Bar-L temp strips cost $9.00, or $25.00 for a 3-pack.
Share the post "Beat the Heat with Barrel Temp Strips"
March 24th, 2014
Brownells’ 8th Annual Gunsmith Career Fair will be held at the Des Moines Marriot Downtown in Des Moines, Iowa, April 1-2, 2014. The Brownells Gunsmith Conference & Career Fair is expected to draw hundreds of attendees along with representatives from three dozen potential employers. As in past years, the Career Fair will include gunsmithing seminars along with opportunities for individuals to interview for jobs with arms-makers and government agencies.
Recent graduates, working gunsmiths, soon-to-graduate gunsmithing students, gun shop owners, and other firearm-related businesses are all invited to attend, as well as anyone interested in beginning a gunsmithing career. According to Frank Brownell: "The Gunsmith Career Fair is the place to network for gunsmiths and companies who employ them. It really is a must-attend event." Those interested can register online at Gunsmith CareerFair.com.
In addition to industry and government representatives, many trade schools and colleges offering gunsmithing programs will be exhibiting at the 2014 Gunsmith fair. Past exhibitors have included:
Story tip by EdLongrange. Reader Submissions are welcome.
Share the post "Brownells 8th Annual Gunsmith Career Fair Runs April 1-2, 2014"
March 16th, 2014
Most long-range benchrest stocks are three inches wide because that used to be the max width under the rules for Light Gun Class. Many folks may not realize that the IBS, the NBRSA, and the Williamsport organizations have all modified their Light Gun rules to allow wider forearm widths in registered competition. A wider stock provides increased stability and resists rotation (torquing) as the gun is fired. If you’re building a new Light Gun, you may want to consider a 4″-wide or 5″-wide forearm. Do check the rules of your local club or regional organization to ensure the wider width is allowed in the matches you attend. And if you plan to shoot F-Class as well, stick to 3″. Under F-Class (Open) rules, “the width of the rifle’s forend shall not exceed 76mm (approximately 3 inches)”.
Wider Forearm Stock Options
Most stock-makers still only offer a 3″-wide forearm width with their Light Gun long-range benchrest stocks. However, there are some other options. On request, Joel Russo, Russo Rifle Stocks, can cut a stock with 4″-wide forearm, but that’s not a standard pattern.
If you want a 4″-5″ wide version of the popular MBR Tooley-style long-range stock, Bill Shehane offers a ‘Big Dawg’ version of his MBR Tracker stock. This features a longer, deeper, and wider fore-end for added stability and more resistance to torque with the heavy calibers. Along with having a wider forearm, the Big Dawg stock is cut 4″ longer than a standard Shehane ST-1000 Tracker. This provides a “longer wheelbase” for better balance with very long (30″+) barrels. (The ST-1000 itself is 3″ longer than most benchrest stocks.) The Big Dawg is available with a 4″-wide or 5″-wide forearm, and will handle barrels up to 40″ in length and 1.5″ in diameter. In the top photo, taken by Forum member Preacher, you see a 4″-wide Big Dawg next to a normal ST-1000 Tracker. (Both stocks are symmetrical; there is distortion caused by wide-angle lens.)
This color pattern is what Bill calls “Prairie Dog Camo”, a Rutland laminate in orange and dark gray, with olive ‘accent’ layers. The price for a ‘Big Dawg’ in Rutland laminate is $625. In African Obeche wood (any color choice), the price is $855.00. For more info, contact Bill Shehane at (704) 824-7511, or visit his website, www.ScopeUsOut.com.
Wide Stocks for Rimfire Benchrest
Ultra-wide stocks are also legal in many rimfire benchrest disciplines. Shown below is a rimfire rifle built with a 4″-wide Shehane Big Dawg stock. This gun is used in ARA Unlimited competition. Extra-wide stocks like this can also be used in the IR 50/50 Unlimited Class and RBA Unlimited Class.
Why use a wide stock for rimfire where recoil is not an issue? The extra width definitely provides more stability in the bags. This is noticeable when cycling the action during the loading process — the gun shows less “wiggle” when opening and closing the bolt. The larger mass of wood also, potentially, provides additional vibration damping. A wider stock design carries more weight (per inch of length) and more mass is distributed outboard. Initial testing shows that the wide stocks work well for rimfire shooters who like to grip their gun — the gun feels “planted” with less wobble when the stock is gripped or cheeked by the shooter.
Share the post "Super-Wide Forearms Add Stability to Benchrest Rifles"
March 11th, 2014
In Brownells’ GunTech™ Archive of instructional articles and videos, Eric Kiesler has written an informative Guide to Metal Prep for bluing or bake-on resin coatings. Eric’s “how-to” advice will be useful for prepping something as small as a scope ring or as large as a complete barrelled action. Here is a selection from Eric’s article:
Gunsmith’s Guide to Metal Prep for Baking & Bluing
By Eric Kiesler
Prior to bluing or the application of a bake-on coating, a steel surface must be properly prepared. In either case, at a minimum the work piece must be thoroughly and completely degreased. There are many acceptable ways to degrease steel parts, so long as no residue remains the method used is not critical. We typically recommend TCE (#083-060-024) for degreasing prior to the application of Brownells Baking Lacquer (#083-046-801) or Oxpho Blue (#082-024-004). The TCE in the spray can is preferable as it allows you vigorously spray the surface, start at the top of the part and hose it down to the bottom chasing the grease off.
Prior to hot caustic Bluing (#082-005-007) the parts are immersed in a heated detergent bath using Dicro-Clean (#082-005-008) because (like TCE) we know it will have no adverse after effects or residue that could cause problems later on. Once the degreasing is complete, the part could be blued or coated, however, with bake on coatings, adhesion is greatly enhanced if the surface of the parts are roughed up. This can be accomplished by sanding them with a fine abrasive cloths, sand paper, Emory Cloth (#657-110-120) or by abrasive blasting. Abrasive blasting is preferable because it will typically reach areas that sand paper might not.
For the Gun Kote (#083-051-001) brand of bake-on finish, aluminum oxide (#084-206-060) must be used as the abrasive blasting media in your abrasive blaster. For our other bake on coatings (and even Aluma-Hyde) sand or glass beads may be used in the blaster. If you do abrasive blast the part (highly recommended), it should be degreased afterwards because the blasting media may have contaminants in it. You don’t want to coat a highly polished part since shiny metal resists the coating, but a highly polished part could certainly be blued.
CLICK HERE to Read Entire Article | CLICK HERE for GunTech™ Archive of Articles
Share the post "Metal Prep for Surface Refinishing (Bluing and Resin Finishes)"
March 10th, 2014
The NRA Gunsmithing Guide contains 336 pages of solid, comprehensive gunsmithing info drawn from articles originally published in the American Rifleman magazine.
The $24.95 book includes 116 articles by expert smiths who build, repair, accurize, and customize all types of firearms (with a strong emphasis on rifles). The three main subject areas are: improving rifle accuracy, customizing fine rifles, and restoring old rifles. Roughly one-third of the articles cover these three topics.
As you would expect from content that first ran in American Rifleman magazine, the articles in the NRA Gunsmithing Guide are richly illustrated with photographs, charts, drawings, diagrams, and data tables. Not Available in bookstores, the NRA Gunsmithing Guide is sold online through Palladium Press, the NRA’s Book Publishing Affiliate.
Click Here for NRA Gunsmithing Guide ORDER Page
Share the post "NRA Gunsmithing Guide Contains 116 Articles"
February 24th, 2014
Looking for a high-quality fiberglass stock at a bargain price? Then check out the Kelbly over-run stocks at PMA Tool. You’ll find a wide variety of stocks on sale at extremely attractive prices (from $200 to $350.00). There are 3″-wide benchrest and F-Class stocks, Hunter Class benchrest stocks, and a variety of general-purpose hunting and varmint stocks. Most of the benchrest stocks are priced at $300.00 to $350.00 — that’s hundreds less than you’d ordinarily pay for a first-tier fiberglass stock from McMillan or other big name manufacturer.
And price isn’t the only attraction. With these Kelbly over-run stocks, there is no waiting. PMA Tool can ship you out a stock in a matter of days. By contrast, you might wait months to get a newly-made stock from another maker. PMA Tool has acquired dozens of Kelbly stocks so there is a large selection. If you go to the PMA website, you can select from three categories of stocks. Then choose a stock that has the appropriate inlet for your action. Some of the over-run stocks are inletted for Pandas, others for BATs, and some for other round actions.
Share the post "Hot Deal: Kelbly Fiberglass Stocks on Sale at PMA Tool"
February 21st, 2014
Most F-TR rifles are essentially prone rifles adapted for use with bipod and rear bags. They feature prone or tactical-style stocks designed to allow a firm grip on the gun, with cheek, hand, and shoulder contact. This has worked very well. Unquestionably, a skilled F-TR shooter can achieve outstanding scores with such a configuration — it works. However, “there’s more than one way to skin a cat”.
At the Berger Southwest Nationals, Eric Stecker introduced a new type of rifle, and a new type of gun-handling, to the F-TR ranks. Shooting “free-recoil” style* (i.e. with virtually no contact on his rifle) Eric managed to finished second overall in F-TR (with the highest X-count), beating some past national champions in the process. Thinking “outside the box” worked for Stecker in Phoenix. The success of Eric’s benchrest-style rifle and shooting technique definitely drew the attention of other F-TR shooters.
Click photo to zoom
Eric’s F-TR rig was built by John Pierce using a stiff, light Scoville carbon-fiber stock. The stock is so light that Eric’s rifle came in 1.5 pounds under the F-TR maximum weight limit (8.25kg or 18.18 pounds). The gun features a Pierce action, Bartlein barrel, Jewell trigger, and a Gen 1 Nightforce 15-55X52mm Comp scope. From the get-go, Eric’s strategy was to “aim small” and shoot his rig like a bench-gun. He actually focused on shooting really small groups rather that just trying to keep shots within scoring rings and “hold waterline”. With a .308 Win that could shoot bugholes at 100 yards, this strategy paid off.
Rifle builder John Pierce explains the thinking behind this rifle: “The stock choice was mine — I had built two prototype rifles last year based on the premise that the game is Benchrest in the prone position. I still feel very strongly regarding [this concept]. I chose Bob Scoville for obvious reasons — he is an artisan and his stocks have won so much, they just flat work. We built Eric the latest configuration along these lines, and the tool worked for him. Without a doubt, Eric is a shooter, and we were all pleased to watch him perform so well.”
Eric sets up rifle before match. During live fire his hands do not contact the stock.
Eric employed a benchrest-style shooting technique with his F-TR rig — he shot pretty much free recoil, with no cheek pressure, no hand contact, and just a “whisper” of shoulder contact. Eric explains: “I shoot what’s called ‘free recoil’. Now the rifle is butted up against my shoulder very lightly, but no other part of my body touches the rifle except for my finger on the trigger.” Eric has even used this technique when shooting a 7mm cartridge in F-Open at other matches: “Someone suggested that this style wasn’t possible with the larger [7mm] cartridges, but I found it very successful so I continue to do it that way.”
Eric also employed an unconventional strategy — he was focused on shooting small groups (not just holding ring values): “Since I have started shooting F-Class, I treat [the target] like a benchrest target. What I mean by that is that I regard the center as my first shot, and so my objective is to create the smallest group. So, I will hold whatever… is required to end up with the bullet ending up in the center — that’s probably true of any F-Class shooter, but I guess the perspective’s a little different when you have a benchrest background.” Eric explained that “maybe I aim a little smaller than others might”, because in the benchrest game, “the slightest miss ends up costing you quite dearly”.
Click to Zoom Photo (This is not Eric Stecker’s rifle, but a “sistership” built by John Pierce.)
Eric Talks about F-TR Trends
Will other F-TR shooters build rifles suited for free-recoil-style shooting? Eric isn’t sure: “I don’t know if this type of rifle is the future of F-TR. I shoot a lot of benchrest, so putting those kinds of components into an F-TR gun made a lot of sense to me. One thing I like about F-TR is that there are a lot of different types of approaches being tried and some of them are successful. So I think it’s still pretty wide-open[.] But I think the really great part of what we found at the Southwest Nationals is that shooting [with] a benchrest-style approach certainly doesn’t hurt you. What I mean by that is … aiming small, trying to make the group as tight as possible rather than trying to hit a particular area. I actually tried to shoot tight groups — that was a focus and that worked for me — I had quite a high X-Count.” NOTE: Eric finished with 51 Xs, 14 more than F-TR Grand Agg winner Radoslaw Czupryna (37X). James Crofts had the second highest X-Count with 48 Xs.
Even Berger’s Boss did pit duty at the Berger SW Nationals.
*”Free Recoil” style shooting has its variations. Some would say “pure free recoil” would not even allow shoulder contact. Eric Stecker lightly touches the back of the stock with his shoulder.
Share the post "Stecker Succeeds at SWN with Radical Benchrest-type F-TR Rig"
February 20th, 2014
Sometimes you’ll get a barrel that doesn’t stabilize bullets the way you’d anticipate, based on the stated (or presumed) twist rate. A barrel might have 1:10″ stamped on the side but it is, in truth, a 1:10.5″ twist or even a 1:9.5″. Cut-rifled barrels, such as Kriegers and Bartleins, normally hold very true to the specified twist rate. With buttoned barrels, due to the nature of the rifling process, there’s a greater chance of a small variation in twist rate. And yes, factory barrels can be slightly out of spec as well.
Before you purchase a bunch of bullets and set off to develop loads it’s wise to determine the true twist rate of your new barrel. Sinclair International, in its Reloading Press Blog provides a simple procedure for determining the actual twist rate of your barrel. Read on to learn how….
How Twist Rate Affects Bullet Stability
Most of you know that the twist of the rifling in the barrel is what puts spin on the bullet. As a bullet is pushed down the barrel and compressed into the rifling, the bullet follows the path or twist of the rifling. The combination of velocity and bullet spin is what stabilizes the bullet. Finding the twist rate for your barrel will help you in selecting appropriate weight bullets for your firearm. Remember, the general rule is that the faster the twist rate for a given caliber, the longer the bullet (of that caliber) you will be able to stabilize. (Generally speaking, a longer bullet will also be a heavier bullet, but the bullet geometry dictates the needed twist rather than the weight per se.)
Determining Barrel Twist Rate Empirically
Twist rate is defined as the distance in inches of barrel that the rifling takes to make one complete revolution. An example would be a 1:10″ twist rate. A 1:10″ barrel has rifling that makes one complete revolution in 10 inches of barrel length. Rifle manufacturers usually publish twist rates for their standard rifle offerings and custom barrels are always ordered by caliber, contour, and twist rate. If you are having a custom barrel chambered you can ask the gunsmith to mark the barrel with the twist rate.
Erik Dahlberg illustration courtesy FireArmsID.com.
Sinclair’s Simple Twist Rate Measurement Method
If are unsure of the twist rate of the barrel, you can measure it yourself in a couple of minutes. You need a good cleaning rod with a rotating handle and a jag with a fairly tight fitting patch. Utilize a rod guide if you are accessing the barrel through the breech or a muzzle guide if you are going to come in from the muzzle end. Make sure the rod rotates freely in the handle under load. Start the patch into the barrel for a few inches and then stop. Put a piece of tape at the back of the rod by the handle (like a flag) or mark the rod in some way. Measure how much of the rod is still protruding from the rod guide. You can either measure from the rod guide or muzzle guide back to the flag or to a spot on the handle. Next, continue to push the rod in until the mark or tape flag has made one complete revolution. Re-measure the amount of rod that is left sticking out of the barrel. Use the same reference marks as you did on the first measurement. Next, subtract this measurement from the first measurement. This number is the twist rate. For example, if the rod has 24 inches remaining at the start and 16 inches remain after making one revolution, you have 8 inches of travel, thus a 1:8 twist barrel.
This rifling illustration was created by Danish graphic artist Erik Dahlberg. It is published here courtesy FireArmsID.com, an excellent website for forensic firearms examiners.
Share the post "Figuring Out Your Barrel’s True Twist Rate…"