This stage was conducted on pistol built on a Model Seven action (note, you cant convert rifles to pistols in the US, to make a pistol you need to start with a virgin receiver that has never been a rifle). While we have went to great lengths to make sure that it's as accurate as possible this rendering should not be used to generate specs for casings. 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). This was the best one. I fired 30 rounds of IMI Samson 150 grain FMJ at 28 and 16.5 and recorded the results. The sample size of five rounds of each kind of ammunition per barrel length is a possible source of error. The cuts were made in one-inch intervals with a rotary saw. 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. December 27, 2014 Furthermore, the 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 real world guns. The 6.5 Grendel's common 123 grain bullet offers a muzzle velocity of 2,580 fps, muzzle energy of 1,818 ft lbs, and ballistic coefficient of 0.506. What are possible sources of error in your experiment? 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. 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. Brian Smyth At each cut length, velocity was measured with a Magnetospeed chronograph. In addition to riding on the back of the 7.62 NATOs short-lived military career, the .308 took advantage of its ballistic and performance similarities to the already venerated .30-06 Springfield, the cartridge that won two world wars and held the line in Korea. I used my iPhone to record a couple shots being fired in slow motion. over what ammo or caliber or gun is "best." tweet/email or post a comment on the blog - one of us will double-check the original For another measure of bullet power, some people prefer to use Muzzle Energy. _gaq.push(['_setDomainName', '.accurateshooter.com']); Obviously, the amount of pressure a thin-skinned brass or steel casing can withstand is incredibly immense. If you liked this postsubscribe to this blog (top right corner of page). This resulted in a velocity loss of 106 feet/second. 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). 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. Would be interesting to find out. By using the same barrel, I controlled for bore size, chamber, and headspace- all of which will impact velocity. Share the post ".308 Win Barrel Cut-Down Test: Velocity vs. Barrel Length", Tags: .308 Win, 7.62x51 cut-down test, Barrel, Rifleshooter.com, Saw, Velocity. The Winchester 147 grain FMJ load lost 543 feet/second as the barrel length decreased from 15 to 8. Compare that to a 5.56 Ball M193 round's 55 grain bullet, which delivers a . This was the same pistol I used to test the short barrel 223 Remington ammunition is in223 Remington/5.56mm NATO Barrel length versus Velocity- Short Barrels- 6 to 14 inches. The rifle is fired at 100 yards, from a bipod with a rear bag, for 5-rounds. var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; My 16.5 308 Winchester (above) is a fun little rifle. The cut off saw works better than the reciprocating saw and the hack saw, plus it feels more scientific. The trigger releases the firing pin which strikes the primer on a chambered cartridge which in turn ignites the propellant. NTX 83176 2050 1450 1070 145 72 39 -1 5 0 -156 So what does the charting of the .308 Winchester's external ballistics tell us exactly? 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. If you think that you discover an error (perhaps a typo) in the data, just drop us a One note: in every case with the T/C Encore the length of the barrel 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. Do a search for .308 and you will find similar results, albeit with fewer references to 7.62. You can find Here are some pics: I get this every so often. For example in this chart I lowered the velocity to . using Hornady 168gr A-MAX Superformance Match factory ammo. Headspace was measured at 1.633+ (.003 over minimum). 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. Cartridge Type: RifleHeight: 2.015"Width: 0.473"Average FPS: 2681Average Energy: 2617Average Gr: 164Recoil: 1.95Power Rank: 4.4 of 20. Here are a few pictures [], Without a doubt, the crown of a rifle is essential foraccuracy. Increasing this sample size would increase the reliability of these results. Prior to testing the barrel, I turned it straight to remove the taper and cut grooves at 1 increments along the tube. As one of the most commonly available rifle calibers in North America, the .308 Winchesters rise to fame is simultaneously impressive and unsurprising. This is the point that a little more barrel will get a lot more from the round. The bolt action pistol with a 5 barrel (above). At 55 grains, its bullet achieves 3,910 fps; at 100 grains, 2,960 fps. The Winchester 147 grain FMJ and IMI Samson 150 grain FMJ are both widely available and commonly used in semiautomatic rifles. The 243 Win's muzzle velocity hinges on its bullet weight. 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. 7.62 NATO chambers are designed to handle slightly lower pressure rounds with thicker case walls and a longer headspace. The answer may surprise you. Hydra-Shok JHP: Speer 200 gr. Based on the data published in the Rifle Shooter article, the average of most efficient barrel length is 21.7 inches. You may not reproduce original text or photos without advanced permission in writing. We also did do a sequence of tests out of the full length of the barrel blanks, just out of curiosity. At 1000 yards a .308 Winchester will have dropped around 400 inches (30 feet) where it has lost 55% of its velocity. Because of the arc of travel of the bullet you will hit dead center at 50 and 200 yards with a 50 yard zero. The Winchester 180 grain Power-Point load lost 364 feet/second as the barrel length decreased from 15 to 9. Troubleshooting seized ejectors. My 22 308 Winchester (above) is my favorite rifle to shoot. Red Oak, White, or Chestnut for Deer Herd? 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. 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. Trajectory for Custom .308 165 TGK #4667 AMMO at 2680 Feet per Second. Time. 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. My lathe is a two hour round trip to the range. Please seeModular Driven Technologies (MDT) LSS Chassis Review. And thanks to our spouses, who were not just tolerant but enthusiastically supportive 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. were either familiar with, or because they were what was available, and mentioning })(); To comment on a post, click Post Title or "Comment" Link. I selected Federal 190 grain Gold Medal ammunition for this test. Do a search on the internet for 7.6251, and you will get results for 7.62 NATO, .308 Winchester, and multiple variants thereof. In 1952, Winchester beat the Army at its own game and launched the new .308 Winchester to the civilian market, a good two years before the 7.6251 saw the Pentagons official green light. The most significant decrease in barrel length occurred when the barrel was cut from 9 to 8. First, lets talk about pressure. Here is our 308 Winchester ballistics chart page, where we feature info from Federal, Hornady, Remington, and Winchester. How to Sight in a Scope - Step by Step Guide. Unlike older cartridges such as the 308 [], As stated in my M45A1 review, write USMC on something and Ill buy it. Test Barrel Lost 22.7 FPS Per Inch (.308 Win Chambering) The headspace on this pistol measured 1.630 (SAAMI minimum), this was .003 less that when the barrel was installed on the rifle (1.633). 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; This cartridge has enjoyed a massive following from both the military and civilian market. Obviously this is a different cartridge type, but also our 6mmBR barrel end length was 5 longer than Rifleshooter.coms .308 Win start length. 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. Looking for the perfect accessories to accompany your new .308 or 7.6251 rifle? I did not control for barrel temperature. The gun and support equipment werent in much better shape. Yes, I am very impressed. The vast majority of rifles, carbines, and pistols chambered in .308 Winchester can safely sling 7.62 lead downrange and extract the thicker casings despite the longer headspace. With tunning accuracy is 99.7%. 0. _gaq.push(['_setAccount', 'UA-6323545-2']); The .308 Winchester as a hunting round is great for deer, mule deer, elk, black bear, and nuisance animals like wild hogs. 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. Or not. Once it reaches 500 yards, it has slowed but it's still maintaining . Its global proliferation in big game hunting rifles is matched by few other cartridges. Mag. The barrel did heat up during firing. Did it really hurt to shoot a short 308 pistol? var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; _gaq.push(['_setDomainName', '.accurateshooter.com']);