_gaq.push(['_setDomainName', '.accurateshooter.com']); How you use the data is entirely var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; Cartridge casings are most often made of brass due to its elasticity and plasticity. 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). Is the reverse possible? The contents of Rifleshooter.com are produced for informational purposes only and should be performed by competent gunsmiths only. _gaq.push(['_trackPageview']); .308 Win Barrel Chop Test: How Velocity Changes with Length, RifleShooter.com .308 Win Barrel Cut-Down Velocity Test, .308 Win Velocity vs. Barrel Length 28 to 16.5 Cut-Down Test, Surprising Results in .223 Rem Barrel Cut-Down Velocity Test, Barrel Length and Velocity in a .223 Rem Barrel Cut-Down Test, http://rifleshooter.com/wp-content/uploads/2015/01/custom-16.5-rem-700-308.jpg. We'd like to personally and specifically thank Pat Childs at Fin & Feather in Iowa City, as he not only helped get most of our 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. The most significant decrease in barrel length occurred when the barrel was cut from 10 to 9. up to you. The bottom picture is the first group I shot with the rifle, 5-shots, .785 including cold bore. 28 barrel ft/sec and 16.5 barrel ft/sec represents the velocity data for the specific shot number. Furthermore, the And more importantly, will one blow up a gun in your face when used in the other? Contact the author here. The small sample size is always an issue. The .308 Winchester / 7.62x51mm NATO was created in 1952 and is based on the .300 savage round a round created in 1920. The 30-30 Winchester 150 gr. The bolt action pistol with a 5 barrel (above). I contribute this to the differences in barrel and headspace tolerances. We stopped at 500 yards, but I had some legit 2.5 500 yard 5 shot groups. Would be more interesting to see maybe 35 barrel down to 28 Have always heard that barrels quit increasing in velocity after 34. The first number is the value of this cartridge, and the last number is the value of the most powerful round in our bullet database. Barrel length, Barrel length and velocity, Cartridge Selection ATTENTION: Effective Sept 1, 2020, the BBTI Project is in "Archive Status." By real* world weapons: Cor Bon 165 gr. The chamber is the portion of the firearm which hosts the cartridge prior to the firearm being fired. Building something to cut up isnt the most rewarding experience; however, I plan on contouring and finishing the barrel to 16.25 (thats why I stopped at 16.5). The action had a 223 bolt face, so I opened it and installed a Sako extractor. polygonal rifling + The barrel was cut off using a cold saw. Good ergonomics, and a great value for the money. Interestingly, these numbers jive pretty well with estimates found in reloading manuals. Coming out of the muzzle, it maintains speeds around 2,750 to 2,800 fps. One note: in every case with the T/C Encore the length of the barrel Ive had small screws fall out of the Jewel HVRs I use on some of my match guns. Thank you. You can find Using one of the many bullet drop calculators available on various ammunition manufacturer websites, we can measure different bullets and distances easily. Cartridge Type: RifleHeight: 2.015"Width: 0.473"Average FPS: 2681Average Energy: 2617Average Gr: 164Recoil: 1.95Power Rank: 4.4 of 20. Average velocity and standard deviation was logged for each round. 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. So what does the charting of the .308 Winchester's external ballistics tell us exactly? 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. If you have a newer 7.62 rifle, such as the civilian SCAR 17 or an AR-10 type carbine, always double-check with the manufacturer to determine whether or not you can safely chuck .308 rounds downrange. In fact the .308 Winchester 165gr bullet is traveling faster at 1000 yards than the .223 or 7.62x39mm at just 500 yds. Copyright GunData.org 2015 | Koenig Media, LLC | Links | Sitemap | Advertise. This was an average decrease of 73.1 feet/second per inch of barrel length. 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. _gaq.push(['_setDomainName', '.accurateshooter.com']); I bought a quart. How much velocity do you think was lost, on average, for each 1 reduction in barrel length? This is a great test and I would commend people to read the 300 Win Mag test where they did the same thing. 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. The velocity and standard deviation are recorded. Ballistics by the Inch (often called BBTI) was a project to test the performance characteristics of a variety of common handgun calibers/cartridges. A. After 15 years Im still working it out. 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. mostly) paid for everything ourselves, and we did not receive any kind of sponsorship The .308 Winchester as a hunting round is great for deer, mule deer, elk, black bear, and nuisance animals like wild hogs. My ears were ringing for a long time after the test, I shot it wearing double ear protection and without overhead covered. Click A. To make the test even more interesting, four different types of .308 Win factory ammunition were chronographed at each barrel length. Troubleshooting seized ejectors. By adding trajectories to the panel on the right you may produce charts and graphs that show the different trajectories side by side. We did all the work. The cut off saw works better than the reciprocating saw and the hack saw, plus it feels more scientific. Fear not. Yes, I do. pistols are measured, but revolvers are measured as the length of the barrel in front of I used my iPhone to record a couple shots being fired in slow motion. the Excel data sheets, with the muzzle energy calculations added in red, on the raw The .327 Fed. Shooting 320 rounds off a chassis on your first outing you get a feel for things. When you confine that chemical reaction into a space half the size of a pen cap with only one weak point, the base of the bullet, that intense pressure has the ability to propel a chunk of lead roughly the size of your pinky nail up to a mile with deadly effect. Initially we intended to test both 9mm and .45ACP cartridges for this sequence. recording sheets. Ive shot a lot of different firearms in my life and this wasnt pleasant. .308 Winchester (7.62mm NATO), Of course, this all takes place within mere fractions of a second. Flawlessly. (function() { Two of the most popular 30 cal cartridges are the 30-06 and 308. The answer may surprise you. Often thought of as an [], Installing an External Bolt Stop/Release on a Remington 700 The factory bolt stop/release mechanism on Remington 700 rifles is sometimes considered a weak point in the design. Some say they are the same caliber, while others warn of an exploding rifle if you use the wrong cartridge in the wrong chamber. Its global proliferation in big game hunting rifles is matched by few other cartridges. Enter your email address to subscribe and receive notifications of new posts by email. All 7.6251 rounds are cool for use in the proper NATO weapon, but 7.62x39 is the original caliber of the infamous AK-47. No, personally, it seems like a silly idea to me. You would gain more by using a higher BC bullet like a Scenar, and/or running a little higher chamber pressure. This project, and all of its results, is only our fault. This was an average decrease of 81.7 feet/second per inch of barrel length. A. Velocity Boundaries (Feet per Second) of: 1740 1460 1460 1460. Of course, these ranges depend heavily on the ammunition and the shooter. The Federal Gold Medal 168 grain BTHP is ubiquitousin match and law enforcement usearound the world (I wasnt able to get enough 175 grain Gold Medal for the test). Mag. A summary of the data for all four cartridges is provided below. 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. NTX 83176 2050 1450 1070 145 72 39 -1 5 0 -156 Very well. The rifle is fired at 100 yards, from a bipod with a rear bag, for 5-rounds. December 27, 2014 This means that when firing a .308 round in a 7.62 chamber, the .308 brass will stretch beyond its intended elastic range. 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. ), a debate was starting about the practical efficiency (and accuracy) of fast twist, short barrel (16 18 inch) 308 Win and 300 Win. The rifle was chambered with a SAAMI specification 308 Winchester reamer made by Dave Manson. ALL Bulletin content is copyrighted, 2023 AccurateShooter.com. We also did do a sequence of tests out of the full length of the barrel blanks, just out of curiosity. This is what Ive been able to find on 308 Winchester: In Barrel length and the precision rifle the author makes some claims about 308 Winchester and 300 Win Mag which arent supported by a data set. The barrel did heat up during firing. 308 Winchester Barrel Length and Velocity: Winchester 147 grain FMJ, 7.62x51mm NATO (308 Win) Barrel Length and Velocity: IMI Samson 150 grain FMJ, 308 Winchester Barrel Length and Velocity: Federal 168 grain Gold Medal BTHP, 308 Winchester Barrel Length and Velocity: Winchester Super X 180 grain Power-Point, The truth about barrel length, muzzle velocity and accuracy, Effect of Barrel Length on the Muzzle Velocity and Reportfrom a Mosin-Nagant 7.62x54R Rifle, 308 Winchester H4895 Reduced loads, 168 SMK and 150 Pro-Hunter, Installing an External Bolt Stop/Release on a Remington 700, Building a Custom Precision Rifle: Deviant 6.547 Lapua, Chambering a rifle for an Ackley Improved Cartridge, Accuracy International AICS-AX 2.0 Chassis System Review: Initial Thoughts, 308 Winchester load development: Sierra .308 195 gr. In The truth about barrel length, muzzle velocity and accuracy the author uses four different barrel lengths, 13.5, 16, 18 and 26.5, and eight different cartridges. This was noticeable from 19 inches and below. While the external dimensions of both 7.6251 and .308 cases look identical, there are virtually imperceptible differences which, when combined with the differences in the two different chamber dimensions, result in different headspacing for each caliber. Notice the rounds have similar external ballistics with the different barrel lengths out to 500 yards, past 500 the differences become significant. This resulted in a velocity loss of 106 feet/second. For example in this chart I lowered the velocity to . 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 7.62x51 NATO is a superior round to the .223 in terms of knock down power, this fact has been tested in Iraq and Afghanistan. Over the past few years, Rifleshooter.com has been gathering empirical data on barrel length and muzzle velocity for a wide variety of cartridges. At each barrel length, the rifle was fired from a front rest with rear bags, with five rounds of each type of ammunition. I had 100% extraction during the course of this experiment. 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. Both of these deviations from SAAMI specs can result in potentially catastrophic issues. over what ammo or caliber or gun is "best." My lathe is a two hour round trip to the range. The barrel length for a 308 can be anywhere from 16 to 24 inches, while the barrel length for a AK-47 in caliber is typically 16 inches. With a barrel reduction from 28 to 16.5, the average speed loss of the four types of .308 ammo was 261 fps total. 300 Winchester Magnum: How Does Barrel Length Change Velocity- A 16 300 Win Mag? Share the post ".308 Win Velocity vs. Barrel Length 28 to 16.5 Cut-Down Test", Tags: .308 Win Barrel, Bill Marr Gunsmith, Cut-Down Test, Rifleshooter.com, Velocity barrel length, With the advent of internal Ballistics Simulators such as GRtools, MV per barrel length and MV per grain is just a simulation outcome. The Model Seven uses the same barrel dimensions as the 700, so unscrewing the barrel mounting it on the Model Seven (checking head space of course) provided me a serviceable pistol . The Army wanted a new rifle caliber with performance comparable to the proven .30-06 but with a shorter overall length, a new wonder cartridge. The barrel was cut off using a cold saw. Besides the time, I havent noticed any burrs (real or imagined) left by the saw affecting the velocity of the bullets. was measured from the end of the barrel back to the breech face. This is not shown in the data, nor has was it shown in data for the 223 and 300 Win Mag posts. Ballistic Trajectory Calculator Ballistic Coefficient Calculator Re: 308 18" barrel Velocity 168 GMM is accurate but does not have the best ballistics available for extended range. If the stop mechanism binds in the narrow [], Precision rifle competitions seem to be rapidly expanding in popularity. So it's not a shocker that the .308 would be a good cartridge. They were fairly close. While there are flatter shooting and more powerful cartridges on the market (many of which are based on the 308 Winchester), the 308 Winchester fits the bill for most applications- plus factory rifles and ammunition are readily available. Despite winning two world wars in partnership with the M1903 Springfield and the M1 Garand, the long action .30-06 Springfield fell out of favor with the U.S. Army following World War II. For instance, 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. At 10-inches, muzzle velocity hasn't reached its peak. Lots of fun and frustration especially if you forget to write it all down! When we cut our 6mmBR barrel down from 33 to 28, we only lost about 8 FPS per inch. Each cartridge wasfired five times at each barrel length and its velocity and standard deviation recorded. DPX: Federal 240 gr. Much Different Results with 6mmBR and a Longer Barrel This allows it to keep a supersonic muzzle velocity at 1,000 yards. Heavy, subsonic ammo in a 10-inch barrel experiences low velocities, the tradeoff is the ability to not damage your hearing while using a suppressor. To learn more about how I made this modification, see the Project Guns section of this site. Test Barrel Lost 22.7 FPS Per Inch (.308 Win Chambering) That is actually not correct. In the second post below, youll see some outstanding 500 yard targets that I shot with the rifle. Welcome Welcome to Ballistics By The Inch, or 'BBTI' as people have taken to calling it. Did it really hurt to shoot a short 308 pistol? This chart shows velocity changes for all four ammo varieties: Summary of Findings: For this stage of the experiment, Ive taken the same barrel used in the rifle length experiment and mounted it to a bolt action pistol built on a virgin Remington Model Seven receiver. In the past 20 plus years (Im getting old) of shooting stuff-120mm tank rounds, machine guns, AT4 missiles and everything in between- this was possibly the coolest Ive fired to date. Ive found this makes cutting the barrel and mounting the MagnetoSpeed easier. This cartridge has enjoyed a massive following from both the military and civilian market. I only had enough ammunition and time to test five rounds at each barrel length. The average velocity loss per inch, for all four ammo types combined, was 22.7 FPS. a debt of gratitude. The testers described their procedure as follows: Ballistic data was gathered using a Magnetospeed barrel mounted ballistic chronograph. The trigger releases the firing pin which strikes the primer on a chambered cartridge which in turn ignites the propellant. Bill Marr 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). SDs and ES were superior from the longer barrel, as was the sight picture. 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. The cuts were made in one-inch intervals with a rotary saw. To make the test even more interesting, four different types of .308 Win factory ammunition were chronographed at each barrel length. Wind Components are (Miles per Hour): DownRange: 0.0 Cross Range: 10.0 Vertical: 0.0. This results in a 7.62 case that is ever so slightly longer than its commercial brother. . My 16.5 308 Winchester (above) is a fun little rifle. CLICK HERE to Read the Rifleshooter.com Test. Gold Dot Short-bbl HP: Henry Big Boy 20" barrel: 1555: 1527: 1613 Youd think I was disappointed, however, there was a smile on my face. Is the file picture at the top of the page real, or photoshopped? 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. Average velocity loss from 28 to 16.5, was 24.6 ft/sec per inch for the Winchester 147 grain FMJ, 22.8 ft/sec per inch for the IMI Samson 150 grain FMJ, 20.9 ft/sec for the Federal Gold Medal 168 grain BTHP per inch, and 22.5 ft/sec per inch for the Winchester Super-X 180 grain Power-Point. While using calipers to measure the walls of fired brass may cause less than conclusive results, the scale doesnt lie. Do a search on the internet for 7.6251, and you will get results for 7.62 NATO, .308 Winchester, and multiple variants thereof. Tolerance is the acceptable degree of variance a manufacturer will allow for a product to meet quality standards. With a barrel reduction from 28 to 16.5, the average speed loss of the four types of .308 ammo was 261 fps total. Super Short Precision Rifles: Is there such thing as a 16.5 .308 Tactical Bolt Action Rifle? Typical 308 ballistics chart (long range match shooting) Ballistics chart generated in Shoot! The test protocol was repeated for the next length. Do you see any use for a 10 308 Winchester? This results in a 7.62 case that is ever so . First, lets talk about pressure. All these details have been generated using our . This calculator will produce a ballistic trajectory chart that shows the bullet drop, bullet energy, windage, and velocity. At each cut length, velocity was measured with a Magnetospeed chronograph. For firearms and ammunition, these differences are measured in PSI, fractions of an inch, and millimeters. What makes the .308 such a good round? Brian Smyth 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. 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. Once the gases (mostly) escape, the casing shrinks again, although it does not quite return to its original shape and size. Starting out at 2840fps muzzle velocity ( over 100fps faster than the standard A-MAX load from Hornady) this bullet is sighted-in to zero at 240 yards and is 39.16 low at 500 yards. Try these too.. Looking for the perfect accessories to accompany your new .308 or 7.6251 rifle? Bill Marr photo link: http://rifleshooter.com/wp-content/uploads/2015/01/custom-16.5-rem-700-308.jpg. No guessing, no models, no arbitrary numbers. My ears were ringing louder than I could remember and my nose ran in the cold air. Or are they different? The heavier weight and newer designed 175gr Sierra . 7.62 NATO (a.k.a., 7.62x51mm) and .308 Winchester are two very common rifle cartridges commonly used by U.S. service members and civilians. All shooting was done from a bench, with a Sinclair rest and rear bag. That works out to an average loss of 22.7 fps per inch. Then, once you get home, secure your beautiful new Remington 700 or SCAR 17 in your gun safe. While the .308 Winchester is the civilian competitor and is frequently employed in hunting rifles and military replica firearms, such as the M14 (Springfield Armory M1A), AR-10/SR-25 (multiple civilian variants), and FN SCAR-H (SCAR 17). If you think that you discover an error (perhaps a typo) in the data, just drop us a As always, Big Army inefficiency slowed down testing and evaluation and, in the meantime, Winchester got hold of the new cartridge dimensions. This includes detailed charts with inch-by-inch velocity numbers, multiple line charts, and complete data sets for each type of ammo. JHP: Cor Bon 225 gr. Velocity loss can be more extreme with shorter barrel lengths (and bigger cartridges). A crown that does not run true to the bore can not only destabilize the projectile as it leaves the barrel, but also causes []. using Hornady 168gr A-MAX Superformance Match factory ammo. (Yes, grains are an actual measurement of weight.). The latter has nearly twice the propellant, and is therefore better able to fell very distant game. The cartridge case (a.k.a. The Federal shows a fairly straight line. 308 Winchester/ 7.62x51mm NATO Comparison of velocity data. var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; Note: I did not run the 180 grain Power-Point because I dont view it as a distance 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. (More powder and more pressure). In the good old days of Precision Shooting magazine (how we miss you! Once data was gathered for each cartridge at a given barrel length, the rifle was cleared and the bolt was removed. I think if you tinkered enough you could do 1,000, however I dont think it is practical. Selecting the best barrel length for the .300 BLK can be a double-edged sword. So, what gives? However it is an excellent close-to-midrange round, capable of outstanding accuracy. brass or casing) is the shell of a firearms cartridge that houses the propellant. Your data showed the 7.6239 mm Russian slowed down from 23 to 24 in barrel length. var _gaq = _gaq || []; Temperature was 47 F.. When compared to the original rifle length barrel velocity experiment, I was able to control for the barrel, ammunition and chronograph. Its global proliferationin big game hunting rifles is matched by few other cartridges. I offered to let him shoot it. The 7.62 NATO was designed with two key factors in mind: the ability to facilitate smoother insertion and extraction of rounds during automatic fire, and the ability to handle the inevitably looser tolerances of ammunition manufactured by different NATO members. The short barrels gas out pretty quickly. This resulted in a velocity loss of 118 feet/second. Turning a sporter contour rifle barrel from a blank, 6.5 Creedmoor loads: 107 SMK IMR 8208 XBR and 142 SMK Superformance 6.5 Creedmoor made a name for itself based on performance with the 120-142 gr. It is outside the scope of this post. Never miss a post! The test protocol was repeated for the next length. At that distance, it retains 400 ft lbs of energy. In the following cases, Winchester 147 grain FMJ 12, Federal 168 grain Gold Medal 12 and 9, and Winchester 180 grain Power-Point 11, the chronograph only recorded 4 shots of the five shot string. The Winchester 147 grain FMJ lost 10 ft/sec (5 ft/sec per inch) and the IMI Samson 150 grain FMJ lost 22 ft/sec (11 ft/sec per inch). .357 SIG, .38 Super Auto Colt, .35 Whelen, .300 Remington Ultra Magnum, .35 Remington, .44 Smith & Wesson Special, .380 Auto (9mm Browning Short), 10mm Auto, .25 Winchester Super Short Magnum (WSSM), .303 British, 6.5x54 MS (6.5 Mannlicher-Schoenauer), .300 Remington Short Action Ultra Magnum, .218 Bee, 6.8mm Remington SPC, .25-20 Winchester.