It includes gauges in .001 increments. Ballistic Trajectory Calculator Ballistic Coefficient Calculator According to multiple non-scientific studies, the average .308 case weighs in around 160 to 170 grains each, while 7.62 brass usually comes in at over 180 grains apiece. At that distance, it retains 400 ft lbs of energy. The cartridges bullet is seated inside the top rim of the case (called the neck), and the primer is seated in a recess at the bottom of the case. While the difference may feel minimal, this means that the interior of 7.6251 brass has less space for powder than a visually identical .308 Winchester case. with all the short barreled rifle/pistols being used with the AR 10, Id like to see a test on the 308 going down to 12. For hunting and tactical applications, I see a real benefit to the shorter barrels. performance comparable to the proven .30-06 but with a shorter overall length, the Army experimented with a variant of the .300 Savage that is designated the T65, a good two years before the 7.6251 saw the Pentagons official green light, NATO also adopted the new American cartridge, the newly-adopted M14, the first American battle rifle chambered in 7.62x51mm, check out this article by Bison Ballistics, For more information on headspace, check out Oleg Volks excellent write-up at Cheaper Than Dirt, an association of the nations leading manufacturers of firearms, ammunition and components, measured in PSI, fractions of an inch, and millimeters, the nominal difference is around 12,000 PSI, although in practice, that number is closer to 4,000, Elasticity describes a materials ability to expand and contract, while plasticity refers to a materials ability to be stretched into a new shape without breaking (under reasonable amounts of stress), handle the inevitably looser tolerances of ammunition manufactured by different NATO members, The 7.6251 NATO chamber is imperceptibly longer than the .308 Winchester, extending between 0.006 and 0.010 inches beyond the .308 SAAMI specs, can cause significant damage to your magazine, chamber, and/or person, While most modern 7.6251-chambered firearms are specced to safely handle .308 cartridges, The U.S. Army lists the 7.62s effective range (and thus, the .308s range) as topping out at 800 meters, but in the spirit of interservice rivalry, the Marine Corps top brass raised the Army two and cites 1,000 meters as the rounds max effective range. mostly) paid for everything ourselves, and we did not receive any kind of sponsorship The average velocity loss per inch, for all four ammo types combined, was 22.7 FPS. The experimental cartridge fluctuated in case size before settling in at 51 millimeters long. _gaq.push(['_setDomainName', '.accurateshooter.com']); It's fine to 600-800 yards and is fine at that range out of an 18" barrel. Released by Winchester in 1952 (and adopted by NATO in 1954 as the 7.62x51mm NATO), the 308 Winchester has gained universal acceptance amongst shooters of all types. The results from Rifleshooter.coms .308 barrel cut-down test are quite different than the results we recorded some years ago with a barrel chambered for the 6mmBR cartridge. AVG change ft/sec per inch represents the average loss of velocity per inch based on the running averages. Average velocity and standard deviation were logged for each round. Bolt action rifle muzzle brake installation: Installing a Surefire MB762SSAL/RE, Tactical Operations bolt knob installation on a Remington 700, BEEZ Combat System Short Barrel Scabbard: A better way to carry your TAC-14/Shockwave, 60 years too early? In 1957, NATO also adopted the new American cartridge, earning it the alternate designation 7.62 NATO. That same year, U.S. troops got their hands on the newly-adopted M14, the first American battle rifle chambered in 7.62x51mm. Doing the opposite is a bit more complicated. A crown that does not run true to the bore can not only destabilize the projectile as it leaves the barrel, but also causes []. The new(ish) .300 Blackout bears a similar (albeit rare) designation of 7.6235, and the standard Russian sniper round is the 7.62x54R. All content Copyright 1998-2018 Rifleshooter.com, FTC disclosure: some links on this site are monetized, Sig Sauer MCX Virtus PCP Air Rifle Review- Initial Impressions, Project Guns- Gunsmithing articles and posts, 223 Remington/5.56 NATO, velocity versus barrel length: A man, his chop box and his friends rifle. The IMI Samson 150 grain FMJ is a 7.62x51mm NATO spec cartridge. While the .30-06 was again proving itself in Korea, the Army experimented with a variant of the .300 Savage that is designated the T65. When the U.S. Army began developing the 7.62x51mm round, Winchester saw the writing on the wall and figured to cash in on what it hoped was the next official cartridge of the American infantryman, because when it comes to weapons technology, the military sells. Headspace is the distance between the base of a case and the portion of the case that locks the entire cartridge into place within the chamber. var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); My 16.5 308 Winchester (above) is a fun little rifle. real world guns. Once it reaches 500 yards, it has slowed but it's still maintaining . The IMI 150 grain FMJ 7.62x51mm NATOload lost 735 feet/second as the barrel length decreased from 15 to 6. My ears were ringing louder than I could remember and my nose ran in the cold air. How to Sight in a Scope - Step by Step Guide. Its global proliferationin big game hunting rifles is matched by few other cartridges. Is the reverse possible? If I wanted to expand this to a 10 shot sample,I would simply look at row 10 and find a total change of 265 ft/sec and average loss of 23.0 ft/sec per inch of barrel. Is the file picture at the top of the page real, or photoshopped? var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); Bill Marr Maybe ask the doctorate students at MIT. Time. With the .30 caliber bullet diameter being translated as 7.62 millimeters, the new 7.62x51mm cartridge was born. Hydra-Shok JHP: Speer 200 gr. Average velocity and standard deviation were logged for each round. Nearly every target shooter had his teeth cut on a 308 Winchester. Two of the most popular 30 cal cartridges are the 30-06 and 308. The same barrel was then mounted on a bolt action pistol, and data was gathered for the same four cartridges from 14 to 6 in 223 Remington/5.56mm NATO Barrel length versus Velocity- Short Barrels- 6 to 14 inches. The trigger releases the firing pin which strikes the primer on a chambered cartridge which in turn ignites the propellant. The 7.6251 NATO chamber is imperceptibly longer than the .308 Winchester, extending between 0.006 and 0.010 inches beyond the .308 SAAMI specs. After 15 years Im still working it out. Much Different Results with 6mmBR and a Longer Barrel The Winchester 147 grain FMJ load lost 543 feet/second as the barrel length decreased from 15 to 8. What makes the .308 such a good round? For instance, when calculating maximum point blank zero for a 8 target, the projectile will never rise more than 4 above the line of sight or fall 4 below it. .32 Winchester Special, .308 Winchester (7.62mm NATO), .38-55 Winchester, .243 Winchester, .300 Remington Short Action Ultra Magnum, .25-35 Winchester, 7.82mm (.308) Lazzeroni Patriot, .260 Remington, .307 Winchester, 6.17mm (.243) Lazzeroni Spitfire, .356 Winchester, 6.71mm (.264) Lazzeroni Phantom, .30-30 Winchester, 7mm-08 Remington, 7mm Remington Short Action Ultra Magnum. Yes, I am very impressed. Ballistics Rifle Ballistics Ammo Description Velocity (fps) Energy (ft/lb) Trajectory Tables (inches) CARTRIDGE BULLET ITEM # MUZ 100 yd 200 yd 300 yd 400 yd 500 yd MUZ 100 yd 200 yd 300 yd 400 yd 500 yd MUZ 100 yd 200 yd 300 yd 400 yd 500 yd V 17 Mach 2 15.5 gr. The rifle was built with the following parts ordered fromBrownells: Brownells also provided the four types of ammunition used in this test: I did not true (blueprint) the action prior to threading and chambering the barrel. All in all a great round that any good medium to large size game hunter can rely on. The barrel did heat up during firing. Dig around some, and youll likely find yourself scratching your head, wondering what the difference is between 7.62 and .308 rounds. 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 This resulted in a velocity loss of 94 feet/second. The PowerRank is an estimation of the cartridge power. This means throwing .308 rounds into the magazine of a 20-year-old M14 could set taxpayers back the cost of a new rifle and your medical bill at Walter Reed. Just ask Todd Hodnett. 28 barrel ft/sec and 16.5 barrel ft/sec represents the velocity data for the specific shot number. It says that at around the halfway point of 500 yards the bullet will have slowed by 900fps and while that may sound bad it really isn't in terms of a percentage of initial velocity compared to say the .223 Remington (would be 1481fps from initial 3214fps) or the 7.62x39mm (would be 1066fps from initial 2349fps). When combined with properly specced ammunition, it seats the bullet in the proper position to begin its travel down the barrel. Bill Marr Like the 5.56 versus .223 comparison, understanding the differences between 7.6251 NATO and .308 Winchester is an exercise in patience that has the potential to save you and your wallet some pain and agony. Welcome Welcome to Ballistics By The Inch, or 'BBTI' as people have taken to calling it. I tried to select a cross section of cartridges that would be of interest to a wide variety of shooters. ga.src = ('https:' == document.location.protocol ? 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. which was specifically designed for long-range target shooting. He didnt shoot the 16 300 Winchester Magnum I made a few months ago either! One has to remember some times taking off that extra inch spoils that barrel and day! _gaq.push(['_setAccount', 'UA-6323545-2']); This is the point that a little more barrel will get a lot more from the round. At each barrel length, the rifle was fired from a front rest with rear bags, with five rounds of each type of ammunition. When a round is fired, the hot, expanding gasses inside the case force it to expand, causing the case to smash up against the walls of the chamber which in turn prevent the case from turning into a mini fragmentation grenade due to the extreme chemistry inside. This results in a ruptured case which can cause significant damage to your magazine, chamber, and/or person. One note: in every case with the T/C Encore the length of the barrel However it is an excellent close-to-midrange round, capable of outstanding accuracy. Red Oak, White, or Chestnut for Deer Herd? 22" is optimum for the 308,Longer will get more velocity, but at a price. 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 rifle used to record data from 26 to 16.5 inches (above). The results from Rifleshooter.coms .308 barrel cut-down test are quite different than the results we recorded some years ago with a barrel chambered for the 6mmBR cartridge. I fired 30 rounds of IMI Samson 150 grain FMJ at 28 and 16.5 and recorded the results. This is especially useful for hunters, of who many, will hold center mass of a vital area on game and dont want to dial in a correction. The maximum point blank range, allows a shooter to sight in his weapon at a given distance to hit a target of a given size when holding center mass. Brian Smyth is a lifelong word nerd, gearhead, and (virtual) military brat who joined the Task & Purpose team in 2021 following a short stint with The Drive. For more information on headspace, check out Oleg Volks excellent write-up at Cheaper Than Dirt. MagnetoSpeed barrel mounted ballistic chronograph. 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 chill from my snow covered feet started to make its way up my legs and into my back. 308 Winchester/ 7.62x51mm NATO Comparison of velocity data. Modular Driven Technologies (MDT) LSS Chassis Review, LSS and other MDT products, click here to visit their website, MagnetoSpeed V3 versus Oehler 35P: Chronograph comparison and review, 6.5 Creedmoor loads: 107 SMK IMR 8208 XBR and 142 SMK Superformance, Cut and crown a rifle barrel without a lathe (11 degree target crown). The chops tests ranged in barrel length from 18" down to 3". The test protocol was repeated for the next length. Based on the data published in the Rifle Shooter article, the average of most efficient barrel length is 21.7 inches. In experienced hands it can hit a 1,000 yard target. We did all the work. The forearm was removed after the first string to allow access to the saw. When you pull the trigger on your M14, it starts a chain reaction. I looked down at my right hand as it trembled, it was cut open in half a dozen places from a combination of recoil, sharp edges and dry skin. If your .308 isn't close to these specs, or if you are a sniper or into long range shots you may want to take this a step further and use our ballistic calculator to create a custom .308 ballistic chart to take into account variances. And if you think you could do better, feel free to spend the money What do you think of the MDT LSS chassis? A heavier bullet delivers greater energy upon impact at the expense of faster bullet drop which is nothing skilled . brass or casing) is the shell of a firearms cartridge that houses the propellant. There are plenty of good sources of information on this topic. Ive referenced a few other 223 Remington studies in my prior posts. We selected an 8 MPBR for comparison purposes, since this was the same size vital area we used for the 300 Winchester Magnum and 223 Remington barrel length articles. The test protocol was repeated for the next length. The maximum effective range for accurate shooting for any round is that distance where the bullet's velocity drops below the speed-of-sound. No complaints, no problems. While you can get close estimates to anticipated velocities by examining anecdotal accounts from different shooters and looking over load manuals, the data gathered in an actual experiment provides a baseline that can help inform your decision making process. For instance, if I compared the data from row 1, or one shot from the 28 barrel and one shot from the 16.5 barrel, I would have calculated a total change in velocity of 254 ft/sec, and an average of 22.1 ft/sec per inch. Ballistics by the Inch (often called BBTI) was a project to test the performance characteristics of a variety of common handgun calibers/cartridges. Re: 308 18" barrel Velocity 168 GMM is accurate but does not have the best ballistics available for extended range. That said, we wouldnt make a habit of it. Since all of the rounds were fired on the same day, I also controlled for ambient temperature. The following is a 1000 yard .308 ballistic chart that was created using our free online ballistic calculator and details all aspects of the bullets trajectory from the millisecond it leaves the barrel until the time it reaches the 1,000 yd mark. Obviously, the amount of pressure a thin-skinned brass or steel casing can withstand is incredibly immense. Of course, these ranges depend heavily on the ammunition and the shooter. I post it here, for free, so other shooters can learn from it. Once data was gathered for each cartridge at a given barrel length, the rifle was cleared and the bolt was removed. *Casing image above is an artist rendering and not a real photo of .308 Winchester (7.62mm NATO) Ballistics cartridge. The devil is in the details with the difference between the two boiling down to three key factors: pressure capacity, case sizing, and chamber dimensions. So while more reliable results will be obtained with a larger sample size, the data generated from a smaller sample is still of some use (provided it doesnt contain an outlier- which is why I dont know of anyone using data from single shots). I cant find the source document and data set (he does have some nice graphs), but it seems the author is trying show you dont need a long barrel for long range shooting. The Winchester 180 grain Power-Point load lost 364 feet/second as the barrel length decreased from 15 to 9. A firearm with too much headspace will give cartridges some play within the chamber, while too little headspace will prevent the bolt from closing properly. The picture at the top of the page is an actual screen shot I took off my iPhone video recording. The .308 just lacks the horsepower for truly long-range shooting. a debt of gratitude. You can find Contrary to the popular urban legend, 7.62 NATO casings do indeed have thicker walls than .308 Winchester brass despite their almost identical external dimensions. This is a very useful test is youre thinking about building a .308 Win hunting rifle, or perhaps thinking of going shorter for your F-TR rifle to save weight. Why you ask? The barrel was cut off using a cold saw. This was an average decrease of 77.6 feet/second per inch of barrel length. Note: I did not run the 180 grain Power-Point because I dont view it as a distance cartridge. Skip to main content; Skip to secondary menu; Skip to primary sidebar; . 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