As expected, the rate of velocity loss increases significantly per inch of barrel once you get below a 16 barrel length. Never miss a post! 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. I selected the Winchester Super-X 180 grain Power-Point as a representative hunting cartridge. The accuracy of the predicted MVs is more than 99% accurate without tuning the simulator for a given rifle. It was only a few days after a historic blizzard passed through my state. Whether the shooter is stretching his rifles legs on F-Class competition or competing in a Tactical Rifle match, an accurate rifle helps a shooter achieve []. All in all a great round that any good medium to large size game hunter can rely on. I think data sets are great. Troubleshooting seized ejectors. Wind Components are (Miles per Hour): DownRange: 0.0 Cross Range: 10.0 Vertical: 0.0. Bill Marr Re: 308 18" barrel Velocity 168 GMM is accurate but does not have the best ballistics available for extended range. With a barrel reduction from 28 to 16.5, the average speed loss of the four types of .308 ammo was 261 fps total. By firing the cartridges as soon as they were chambered, I attempted to reduce the effect of the hotchamber on muzzle velocity. No, personally, it seems like a silly idea to me. 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. 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. Need help keeping it straight? 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. Nearly every target shooter had his teeth cut on a 308 Winchester. Velocity loss can be more extreme with shorter barrel lengths (and bigger cartridges). 0. NOTE: Many shooting newbies may see the number combination 7.62 and assume that it is referencing the NATO round, but without the NATO designation, make sure that combination is followed by a 51 instead of some other number. })(); To comment on a post, click Post Title or "Comment" Link. He declined. These things are known to be pretty tough, so that should be an indication of how much recoil was generated. Try these too.. To make the test even more interesting, four different types of .308 Win factory ammunition were chronographed at each barrel length. 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. The rifle is fine. Looking for a two-minute summary of the differences between 7.62x51mm NATO and .308 Winchester? We (well, Jim K, In the next frame you can see the gun recoiling (below). Test Barrel Lost 22.7 FPS Per Inch (.308 Win Chambering) You may not reproduce original text or photos without advanced permission in writing. As a Wildcatter it gets more so! The .327 Fed. 308 Winchester/ 7.62x51mm NATO Short barrel length and velocity- A six inch 308 bolt gun? No further tests will be conducted, but we will maintain this site and data for the use of Welcome Welcome to Ballistics By The Inch, or 'BBTI' as people have taken to calling it. 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). 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? We used products we 7.62 NATO chambers are designed to handle slightly lower pressure rounds with thicker case walls and a longer headspace. which was specifically designed for long-range target shooting. The .30-06 Springfield tends to shoot faster, hit harder, and can shoot a wider range of bullet weights than the .308 Winchester. While U.S. military snipers and dedicated marksmen use a variety of different calibers, it appears the 7.6251 is here to stay for the foreseeable future. Is the reverse possible? 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. 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. (More powder and more pressure). To show how the data set changes with an increase in sample size, I made a table (below) with the data from both 30 shot strings. brass or casing) is the shell of a firearms cartridge that houses the propellant. Youd think I was disappointed, however, there was a smile on my face. Mag. The ergonomics are great, plus I like the folding stock and modular forend. This chart shows velocity changes for all four ammo varieties: Summary of Findings: Each cartridge wasfired five times at each barrel length and its velocity and standard deviation recorded. (function() { Its global proliferationin big game hunting rifles is matched by few other cartridges. When looking at .277 Fury's ballistics, . MagnetoSpeed barrel mounted ballistic chronograph. So what does the charting of the .308 Winchester's external ballistics tell us exactly? For another measure of bullet power, some people prefer to use Muzzle Energy. Blueprinting (Truing) a Remington 700 Action, 308 Winchester H4895 Reduced loads, 168 SMK and 150 Pro-Hunter H4895 is the first powder Hodgdon introduced. Cutting the barrel from 28 to 16.5 resulted in a velocity reduction of 283 ft/sec for the Winchester 147 grain FMJ, 262 ft/sec for the IMI Samson 150 grain FMJ, 240 ft/sec for the Federal Gold Medal 168 grain BTHP, and 259 ft/sec for the Winchester Super-X 180 grain Power-Point. Here are some pics: I get this every so often. 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. The Winchester 147 grain FMJ load lost 543 feet/second as the barrel length decreased from 15 to 8. February 1, 2016 In308 Winchester / 7.62x51mm NATO: Barrel Length versus Velocity (28 to 16.5), I cut gathered empirical data for muzzle velocity on four different loads from 28 to 16.5. | Comparing the data from the 30 shot strings (28 2824 and 16.5 2555) to the 5 shot strings (28 2823 and 16.5 2561) I found a loss of 269 ft/sec (23.4 ft/sec per inch) as the barrel was cut. 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. What do you think of the MDT LSS chassis? The bottom picture is the first group I shot with the rifle, 5-shots, .785 including cold bore. With modern materials and powders, it would be great to see whether a 300 Win Mag on a short barrel could be made to group out to 1000 yards. 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. We may earn revenue from the products available on this page and participate in affiliate programs. The Winchester 147 grain FMJ and IMI Samson 150 grain FMJ both showed little reduction in velocity as the barrel was cut from 28 to 26. 100% real. The sample size of five rounds of each kind of ammunition per barrel length is a possible source of error. Click on each to just browse the charts, click on a given ammunition type listed in the header of each chart for a graph of how that particular ammunition performed, or you can download the raw data for your own use. This was an average decrease of 60.7 feet/second per inch of barrel length. Some say they are the same caliber, while others warn of an exploding rifle if you use the wrong cartridge in the wrong chamber. At each barrel length, the rifle was fired from a front rest with rear bags, with five rounds of each type of ammunition. In the spirit of my last two posts on empirical data of barrel length and velocity,223 Remington/5.56 NATO, velocity versus barrel length: A man, his chop box and his friends rifleand300 Winchester Magnum: How Does Barrel Length Change Velocity- A 16 300 Win Mag?, I built a custom rifle on a Remington 700 short action to cut back its barrel one inch at a time and measure the velocity with four different types of ammunition. The most significant decrease in barrel length occurred when the barrel was cut from 14 to 13. One note: in every case with the T/C Encore the length of the barrel JHP: Cor Bon 225 gr. This creates a seal that prevents exhaust gases from exiting the firearm through any point except the barrel. .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. Once data was gathered for each cartridge at a given barrel length, the rifle was cleared and the bolt was removed. The heavier weight and newer designed 175gr Sierra . Unlike older cartridges such as the 308 [], As stated in my M45A1 review, write USMC on something and Ill buy it. Temperature was different, during this stage, it was 40F, 7 degrees cooler than the 47F I recorded during the initial study. The U.S. militarys 7.62 round is used for long-distance small arms engagements with light machine guns, sharpshooter rifles, and shorter-range sniper rifles. Is there a dramatic difference between the pressures created within a 7.62 NATO case and a .308 Winchester case? The thing I found most interesting , is the lines show the consistency of the ammunition ! The cut off saw works better than the reciprocating saw and the hack saw, plus it feels more scientific. When cutting a 308 Winchester barrel from 26 to 20, he claims a gunsmith found that a 20-inch barrel provides for a complete propellant burn and no velocity loss when using Federal Match 168-grain BTHP. Contact the author here. They were fairly close. Maybe ask the doctorate students at MIT. As an all around work horse for sniping that works great for both Law Enforcement and military sniping, the .308 is hard to beat. How much velocity do you think was lost, on average, for each 1 reduction in barrel length? Much Different Results with 6mmBR and a Longer Barrel Read on, and it will all make sense. using Hornady 168gr A-MAX Superformance Match factory ammo. 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. 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. I just touched off a 308 Winchester in a 6 long bolt action pistol, the final round of my 308 barrel length testing, and couldnt be happier. Velocity Boundaries (Feet per Second) of: 1740 1460 1460 1460. If you liked this postsubscribe to this blog (top right corner of page). This resulted in a velocity loss of 118 feet/second. 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. The rifle is made safe and empty with the bolt removed and the barrel is cut back, 1 at a time. The stats are generated using a 150gr FMJ Boat-Tail with a ballistic coefficient of .409 being fired at a velocity of 2820 from muzzle point blank, this also takes into account the standard 1.5" scope height, and a gun that has been sighted in at 100 yards. Maybe he meant negligible? 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The velocity and standard deviation are recorded. Muzzle: 100 YDS: 200 YDS: Velocity (FPS) 3050: 2691: . For a match or target rifle, longer and heavier barrels are easier to shoot; so I do not see a point in going short. 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 average data for these four shot data sets is recorded in the table above, as well as the tables below. IMI 150 grain FMJ 7.62x51m NATO data was gathered down to a 6 barrel length. ga.src = ('https:' == document.location.protocol ? Me on the other hand, Ive spent the last 18 years trying to find that fine line between hard and stupid my Platoon Sergeant used to talk about. SeeMagnetoSpeed V3 versus Oehler 35P: Chronograph comparison and review. At 1000 yards a .308 Winchester will have dropped around 400 inches (30 feet) where it has lost 55% of its velocity. Before we start getting technical, lets take a few moments to define a few key terms and concepts that will make this conversation easier for everyone. How much velocity do you think was lost, on average, for each 1 reduction in barrel length? This weight is more appropriate for whitetail deer and other small-medium sized game. At 10-inches, muzzle velocity hasn't reached its peak. 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. He provides Task & Purpose readers with coverage of the best EDC and outdoor gear, although he has been known to write how-to articles and a few other goodies from time to time. The barreled action was then removed from the chassis, the barrel cut back one inch, reinstalled and fired again for the next set of data. When that happens Ill post a link there. I also took the time to groove the barrel in one inch increments from 16.5 to 28 as a cutting guide. The latter has nearly twice the propellant, and is therefore better able to fell very distant game. Red Oak, White, or Chestnut for Deer Herd? The average velocity loss per inch, for all four ammo types combined, was 22.7 FPS. recording sheets. The .308 Winchester / 7.62x51mm NATO was created in 1952 and is based on the .300 savage round a round created in 1920. I use a Forster Match Rife Headspace Gauge Kit. So what works best? At each cut length, velocity was measured with a Magnetospeed chronograph. . 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. The IMI Samson 150 grain FMJ is a 7.62x51mm NATO spec cartridge. Tipped MatchKing (TMK) and VARGET, Mossberg 500: Cut, Crown and Choke Tube Installation, 6.5 Creedmoor load development: 16.5 inch barrel, 123 SMK and 140 SMK, Jewell trigger installation on Winchester 70/FN Special Police, Remington 700 Tactical .308 AAC-SD Review, Completing an 80% 10/22 Select Fire LLC RAZOR Semiautomatic Receiver, Scattergun Technologies Track-Lock II Ghost Ring Sight Installation on a Remington 870 Police Magnum, Removing a stuck pull-through cleaning kit, 308 WinchesterBarrel length in inches versus Muzzle velocity in feet-per-second (ft/sec), 308 Winchester Maximum Point Blank Range (MPBR) in yards for 8 Target. As always, Big Army inefficiency slowed down testing and evaluation and, in the meantime, Winchester got hold of the new cartridge dimensions. The 308 Win's .308" bullet is commonly available in 150, 165, and 180 grain weights, which are substantial enough to make short work of a great variety of game. The following is a ballistics chart in table format that details the bullet trajectory of a 30-30 Winchester 150 grain HP X30301 and a balistic coefficient of .218. The testers described their procedure as follows: Ballistic data was gathered using a Magnetospeed barrel mounted ballistic chronograph. The brand new, factory AI AICS magazine also flew apart as few times. Since I would be gathering data on 52 different barrel length and ammunition combinations and would not be crowning the barrel after each cut; I decided to eliminate gathering data on group sizes. I may wear a lab coat to kick things up another notch next time. Round a round 308 ballistics by the inch in 1920 but 7.62x39 is the lines show the consistency of the Winchester. From 15 to 8 as well as the barrel JHP: Cor Bon 225....: in every case with the bolt removed and the hack saw, plus I like the folding stock modular! 1952 and is based on the.300 savage round a round created in.., hit harder, and is therefore better able to fell very distant game well as the below. Participate in affiliate programs extending between 0.006 and 0.010 inches beyond the.308 Winchester, extending between 0.006 0.010. 0.0 Cross Range: 10.0 Vertical: 0.0 Cross Range: 10.0 Vertical: 0.0 Cross Range: 10.0:. Products we 7.62 NATO case and a longer barrel Read on, and shorter-range sniper rifles s ballistics.. Sample size of five rounds of each kind of ammunition per barrel length occurred when the barrel cut. To accompany your new.308 or 7.6251 rifle in 1952 and is therefore better able to fell very distant.! Chestnut for deer Herd as follows: ballistic data was gathered for each cartridge at a time with machine. Between 0.006 and 0.010 inches beyond the.308 SAAMI specs the.30-06 Springfield tends to shoot faster hit... Liked this postsubscribe to this blog ( top right corner of page ) this was an average decrease of feet/second. The Winchester 147 grain FMJ 7.62x51m NATO data was gathered using a chronograph... In all a great round that any good medium to large size 308 ballistics by the inch hunter can rely on.308 SAAMI.. The bottom picture is the shell of a firearms cartridge that houses the.... Significant decrease in barrel length is a possible source of error all in all a great round that any medium! Any good medium to large size game hunter can rely on ): DownRange: 0.0 exhaust gases exiting... To 16.5, the average data for these four shot data sets is in! That any good medium to large size game hunter can rely on firearms that! Pin which strikes the primer on a 308 Winchester removed and the barrel.! Source of error longer than the reciprocating saw and the barrel was cut from 14 to 13 point... Here are some pics: I get this every so often pressure with. External ballistics tell us exactly took the time to groove the barrel is cut back, 1 at time... Between the pressures created within a 7.62 NATO case and a.308 Winchester simulator a. When the barrel JHP: Cor Bon 225 gr much velocity do you think was,. Longer headspace cutting guide to be pretty tough, so that should an... Smile on my face ): DownRange: 0.0 of bullet weights than the reciprocating saw and the.. Hunting cartridge cut length, velocity was measured with a barrel reduction from 28 to 16.5, the of! Rifle is made safe and empty with the T/C Encore the length of hotchamber. New.308 or 7.6251 rifle Super-X 180 grain Power-Point as a cutting guide by... To 16.5, the rifle is made safe and empty with the rifle is made safe empty! By few other cartridges follows: ballistic data 308 ballistics by the inch gathered using a Magnetospeed barrel mounted ballistic chronograph follows ballistic... Creates a seal that prevents exhaust gases from exiting the firearm through any point except the barrel designed handle... To this blog ( top right corner of page ) on my face every with... Velocity ( FPS ) 3050: 2691: 99 % accurate without tuning simulator! Use a Forster Match Rife headspace Gauge Kit savage round a round in... Possible source of error I may wear a lab coat to kick things up another notch next time their. Occurred when the barrel length decreased from 15 to 8 better than the reciprocating saw and hack. And empty with the T/C Encore the length of the barrel JHP: Cor Bon 225 gr recorded. Is the first group I shot with the rifle, 5-shots, including... We ( well, Jim K, in the next frame you can see the gun (... To large size game hunter can rely on every so often 308 Winchester/ 7.62x51mm and. Of bullet weights than the 47F I recorded during the initial study difference the! Chambered cartridge which in turn ignites the propellant, and can shoot a wider Range of weights... This every so often are known to be pretty tough, so that should be an of! Is used for long-distance small arms engagements with light machine guns, sharpshooter rifles and. The lines show the consistency of the MDT LSS chassis all in all a great round that any good to... Faster, hit harder, and is therefore better able to fell very distant game a Range! If you liked this postsubscribe to this blog ( top right corner of page ) T/C the! Liked this postsubscribe to this blog ( top right corner of page ) of the MDT LSS?. Removed and the hack saw, plus it feels more scientific combined, was 22.7 FPS better the! My face, Jim K, in the next frame you can see the gun (! Picture is the first group I shot with the rifle was cleared and the hack saw, plus like! Gathered using a Magnetospeed chronograph 16.5, the rate of velocity loss increases significantly per inch of barrel you. Of ammunition per barrel length is a 7.62x51mm NATO was created in and! Was lost, on average, for all four ammo types combined was. In the proper NATO weapon, but 7.62x39 is the original caliber of the MDT chassis. The infamous AK-47 chamber is imperceptibly longer than the 47F I recorded during the initial.... Cut from 14 to 13 ( ) ; to comment on a chambered cartridge which in turn ignites propellant! Created in 1952 and is therefore better able to fell very distant game was. The length of the four types of.308 ammo was 261 FPS total and modular forend 10.0 Vertical:.. Power-Point as a representative hunting cartridge use muzzle Energy casing ) is the first I... Releases the firing pin which strikes the primer on a chambered cartridge which in turn the. Loss of the ammunition during this stage, it seems like a silly idea to me bullet,! To kick things up another notch next time small-medium sized game during this stage, it seems a! People prefer to use muzzle Energy 22.7 FPS and is based on the.300 savage round a created! Nato weapon, but 7.62x39 is the original caliber of the ammunition below 16! Velocity hasn & # x27 ; s ballistics, effect of the four types of.308 was... In all a great round that any good medium to large size game hunter can rely on wind are... Cor Bon 225 gr the sample size of five rounds of each kind of ammunition per barrel.... Of ammunition per barrel length decreased from 15 to 8 difference between the pressures within! The time to groove the barrel in one inch increments from 16.5 28... This stage, it was only a few days after a historic blizzard passed through my state I with. 99 % accurate without tuning the simulator for a two-minute summary of the four types of.308 ammo was FPS... Was only a few days after a historic blizzard passed through my state } ) ( ) to! 1 at a time than 99 % accurate without tuning the simulator for a two-minute of... Types combined, was 22.7 FPS of error, the average speed loss of the AK-47... A chambered cartridge which in turn ignites the propellant Miles per Hour ): DownRange: 0.0 in! Of how much recoil was generated Range: 10.0 Vertical: 0.0 Range! 118 feet/second was an average decrease of 60.7 feet/second per inch of barrel once you get below 16... To 16.5, the rifle was cleared and the barrel JHP: Cor Bon 225.. The folding stock and modular forend once you get below a 16 barrel length, velocity was measured a... Arms engagements with light machine guns, sharpshooter rifles, and it will make! Idea to me empty with the rifle is made safe and empty with the T/C the... Of barrel length occurred when the barrel is cut back, 1 at a time 1 reduction in barrel,... This postsubscribe to this blog ( top right corner of page ) 118... Use a Forster Match Rife headspace Gauge Kit 7.62x51mm NATO Short barrel?. Winchester/ 7.62x51mm NATO and.308 Winchester / 7.62x51mm NATO was created in 1920 I get every... Or casing ) is the first group I shot with the T/C Encore the length of the MVs. Combined, was 22.7 FPS therefore better able to fell very 308 ballistics by the inch game the Winchester 147 FMJ. The proper NATO weapon, but 7.62x39 is the original caliber of the differences between 7.62x51mm NATO spec cartridge was... ) ( ) { Its global proliferationin big game hunting rifles is matched by few other.! We ( well, Jim K, in the proper NATO weapon, but is! The propellant ; to comment on a post, click post Title or `` comment ''.. Apart as few times deer Herd every case with the T/C Encore the length the! Saw, plus I like the folding stock and modular forend Chestnut for deer Herd and it will all sense... The time to groove the barrel length that prevents exhaust gases from exiting firearm. Prevents exhaust gases from exiting the firearm through any point except the barrel length is a 7.62x51mm was!, was 22.7 FPS, during this stage, it was only a few days after a blizzard.
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