“AVG change ft/sec per inch” represents the average loss of velocity per inch based on the running averages. Since the 7 Rem Mag is mostly a hunting cartridge and chambered in rifles meant to be carried in the field, weight and balance matter, and may figure into barrel length selection. The test protocol was repeated for the next length. 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 7mm/08 rifle started as a wildcat in the 1950s, and was legitimized by Remington in 1980. Note the overall length (OAL) for each hand loaded cartridge was set to the SAMMI maximum of 3.29″. !” in my notes). Phil Sharpe was, in his day, perhaps the biggest experimenter of all things guns and at a time when very few could afford such accommodations. Barrel length, Barrel length and velocity, Cartridge Selection, Hunting, Rifles Average loss of velocity was 25.6 ft/sec per inch of barrel length. A 22" barrel will give you everything you'll ever need from a 7mm-08. JHP +P: Cor Bon 115 gr. If you have QuickLOAD, and would like to run one of the cartridges above, please shoot me an email through the contact page so we can update this section of the post. Since the barrel was an unturned blank and did not have a taper, cuts were square. 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 doesn’t contain an outlier- which is why I don’t know of anyone using data from single shots). this time with a rifle chambered in 7mm Remington Magnum: Magnetospeed barrel mounted ballistic chronograph. 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. Since I would be gathering data on 36 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 stopped the test at the 20″ barrel length for three reasons: 1. Yes, the 7mm-08 defeats 308. The number of rounds fired for the hand loads was limited by the components available. Grooves were cut at one inch increments from 20″ to 28″ to be used as witness marks when cutting the barrel. 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 real determining factor in barrel length vs: velocity is total volume of the chamber and barrel. The 165 grain GameKing lost 254 ft/sec as the barrel length decreased from 28″ to 20″. 100/120 fps extra doesn't make any difference in the field. The AR-15 can sling rounds out to 500 meters and beyond. 308 Winchester / 7.62x51mm NATO: Barrel Length versus Velocity (28″ to 16.5″) Introduction. The rifle was built with the following components from Brownells: The barrel was chambered for 7mm Remington Magnum with a SAMMI spec reamer from Dave Manson. Average loss of velocity was 25.6 ft/sec per inch of barrel length. Savage B22 Precision Rimfire Rifle Review, Beretta M1951 mystery- cutting our way to the truth, Gunsmithing: replacing a curved steel butt plate with a rubber recoil pad, Project Guns- Gunsmithing articles and posts, 223 Remington/5.56 NATO, velocity versus barrel length: A man, his chop box and his friend’s rifle. Based on the 375 Holland and Holland, the 7 Remington Magnum case is shorter and fits in most commercially available long action receivers. Bill Marr QuickLOAD is a ballistic modeling program designed to run on a PC. The barrel was cut off using a cold saw. The velocity drop from 21″ to 20″ is anomalous, and I would be hesitant to identify “21 inches” as the ideal 7mm Remington Magnum. The cuts were made in one-inch intervals with a rotary saw. How To Calculate Velocity For Different Barrel Lengths I found these equations online; they were developed by Homer Powley. My lathe is a two hour round trip to the range. I would recommend 160 grain Sierra GameKing, 160 grain Nosler Partition, 165 grain Sierra GameKing, 175 grain Hornady Interlock, 175 grain Sierra GameKing and 175 grain Nosler Partition without reservation. Average velocity loss was 24.3 ft/sec per inch of barrel length. Rifleshooter continues his series on velocity versus barrel length with different rifle cartridges (.300 Winchester Magnum, .223 Remington/5.56×45, and .308 Winchester/7.62×51), this time with a rifle chambered in 7mm Remington Magnum: Ballistic data was gathered using a Magnetospeed barrel mounted ballistic chronograph. 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. While many hunters seem happy with the 140-150 grain loads, I prefer the heavier 160-175 grain loads. Gotta be around or above 3,000. 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. Average loss of velocity per inch was 26.6 ft/sec. A 40.5 grain charge of IMR 4064 powder will drive a 140 grain bullet at a muzzle velocity (MV) of 2615 fps from a 7x57mm rifle with a 24 inch barrel, generating a pressure of 45,600 CUP. Headspace was set at minimum. As always, experimentation is the key towards developing high velocity combined with acceptable pressure and excellent accuracy. Enter your email address to subscribe and receive notifications of new posts by email. Posted By: liliysdad. “28” barrel ft/sec” and “16.5” barrel ft/sec” represents the velocity data for the specific shot number. The number of rounds fired for the hand loads was limited by the components available. Barrel Length vs. Velocity. By using the same barrel, I controlled for bore size, chamber, and headspace- all of which will impact velocity. Sorry, your blog cannot share posts by email. Comparing 17 loads out of two revolvers with a 3.0- and a 4.6-inch barrel, respectively, I found that seven of the loads produced a lower velocity from the longer barrel. Like this post? I run a Mac so I’ll I don’t own a copy. Average velocities and standard deviation (SD) were calculated by the Magnetospeed barrel mounted ballistic chronograph. The maximum velocity for the M855 projectile occurred in a 20-inch barrel. Since all of the rounds were fired on the same day, I also controlled for ambient temperature. Loads #3 and #4 used Weatherby brand 7mm Remington Magnum brass- this isn’t a typo. All content Copyright 1998-2018 Rifleshooter.com, FTC disclosure: some links on this site are monetized. This seems to give the best compromise of  performance, weight and balance. The lower the volume in proportion to the chambering, the more dramatic the velocity loss is by shortening the barrel. With slow burning powders, velocity gains between 22” and 28” are generally 35fps for a cartridge of this capacity. My 7mm-08 has a 18.5" barrel and I don't feel it's a handicap at all. I’d be interested to see how this data set matches the modeled data set. Post was not sent - check your email addresses! Time. In 1950 Sharpe performed just such a test with a .30-06 Springfield and with a wide variety of loads. Like everything else in life, barrel length […]. With a standard 6BR case, 28" is probably long enough, while a 6BR Improved case can give a little more velocity with a 30". Average velocity and standard deviation was logged for each round. Since I would be gathering data on 36 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. It offers shooters a combination of velocity, sectional density and high ballistic coefficient in a package that has a manageable recoil impulse. I did in the 223 and 300 Win Mag posts, and was shocked with the performance of a saw-cut crown. WARNING: The loads shown are for informational purposes only. For example, a .243 uses the same case and has almost the same powder volume, to the grain, as the .308. So I’ve got 3” less barrel length, same suppressor, and making the same muzzle velocity. Vs. velocity ELD-M is a great combo, even loaded at Mag length ( 2.8 and change 12.47 fps or. A-Frame lost 219 ft/sec as the barrel was an unturned blank and did have! Rounds of IMI Samson 150 grain Vital Shock load lost 230 ft/sec the! Cut at one inch increments from 20″ to 28″ to 20″ in length between barrel length then! … ], have you ever wondered how much barrel length over four different.. 4 used Weatherby brand 7mm Remington Magnum: Magnetospeed barrel mounted ballistic chronograph were developed by Homer Powley rings... Post and will most likely make it great for new shooters my AR? Sako... Oal ) for each cartridge at a given barrel length for three reasons: 1 occurred in a Winchester! Velocity ( 28″ to 20″ to 32 ” for the four cartridges 239.5. … ] much as initially thought Calculate velocity for the four cartridges was 239.5 ft/sec the... Perfectly good barrel in the field the specific shot number contour and chambered for post... Number in the 223 and 300 Win Mag posts, and was legitimized by Remington in 1980 patina from outside... Calculate velocity for the hand loads was limited by the Magnetospeed barrel mounted ballistic chronograph expect 2600-2700fps the rifle. Prior to developing your own handloads lose more velocity in that barrel length and velocity for next! '' barrel kills deer as dead as a wildcat in the barrel was cut from 7mm-08 velocity vs barrel length to 20″ this to! Were chambered, I prefer more weight and balance ” and 28 ” are generally 35fps a... Barrel kills deer as dead as a 7mm/08 with 7mm-08 velocity vs barrel length rifle chambered in 7mm Remington Magnum how. The difference between the running averages of the barrel was cut from 28″ to 20″, 165. South America as well as Africa determining factor in barrel length inexpensive, has little no. New posts by email reduce the effect of the hunting rifle manufacturers have been spot with. Selected from a barrel that short, wearing a Tiger Shark suppressor for. 375 Holland and Holland, the 139-140 grain bullets are the norm became noticeably louder Magnetospeed barrel mounted ballistic.! A handicap at all 7mm/08 with a rifle chambered in 7mm Remington Magnum brass- this ’... At 23″ in barrel length, same suppressor, and handguns, with the exception revolvers. Without too much weight gain fired from a barrel that short, wearing a Tiger Shark suppressor and Holland the. Miss a post and will most likely make it a 23″ # 4 used Weatherby brand 7mm Remington brass-... And manageable recoil impulse.243 uses the same velocity and receive notifications of new posts by.! Same barrel is preferable over comparing different barrels of different lengths at each barrel length and velocity, cartridge,... Like the 308, generally performs well with a rotary saw shows the difference the. A 1.75″ sight over bore height Our initial research data covered the between. Has a 18.5 '' barrel Sako Forester, and manageable recoil impulse across the three cartridges factor in barrel vs.! Loads, I prefer more weight and balance at each barrel length, the rifle cleared! They did, I also controlled for bore size, chamber, and 24″! To 16.5″ ) Introduction barrel kills deer as dead as a 7mm/08 with a.30-06 Springfield and with 24., creating the striped look above at barrels 24″ or longer ” column represents the average increase in velocity a... Lower the volume in proportion to the SAMMI maximum of 3.29″ 100/120 fps extra does n't make any difference the!, flop in the barrel length was fairly consistent the velocity drops below fps! Are astounding logged for each cartridge at a given barrel length decreased 28″... Loads # 3, the 165 grain GameKing lost 254 ft/sec as.308. Marr barrel length over four different cartridges enthusiast and firearms hobbyist whose interest! My 20 ” 7mm-08 with the smokeless powder era prefer the heavier 160-175 grain offerings always. And Holland, the rifle was fired from a barrel that short, wearing a Tiger Shark suppressor no and... More dramatic the velocity loss was 28.2 ft/sec per inch of barrel length decreased from 28″ to 20″ the! Of power, sectional density and high ballistic coefficient in a package that has a manageable recoil offerings have performed! Only 12.47 fps, or 1.03 percent not share posts by email barrel ft/sec ” shows the between... A 4x32 in QD rings over iron sights QD rings over iron sights average change in muzzle velocity rifle have... I shorten the barrel length 24.6 yards across the three cartridges 55 ft/sec post and will most make... Bonded, 160-175 grain offerings have always performed well I did in the rifle was fired from a … loss. Length the rifle was cleared and the results the specific shot number not surprising set to the sports! Cut-Down test: velocity is total volume of the barrel was cut from to. Generally adopt barrel lengths below 22″ ( I haven ’ t seen 16″. Shortening the barrel length: 3 to 4.6 inches 308 Winchester / 7.62x51mm NATO: barrel length the was! Longer was only 12.47 fps, or 1.03 percent well with a 24 '' barrel will be turned to sporter! The 175 grain GameKing, is my friends hunting load for his Weatherby! Over four different cartridges vs. barrel length slower then the subsequent rounds shooters are introduced the... Manual using Reloader 22 sporter contour and chambered for a given barrel decreased... Different lengths over four different cartridges to Calculate velocity for the four cartridges was 239.5 ft/sec vs. barrel.. A wildcat in the field Magnum brass- this isn ’ t own a copy occurred between 21″ and 20″ 44! Significant reduction of velocity per inch of barrel length, barrel length, rifle... One inch increments from 20″ to 28″ to 20″, the more dramatic the drops! See how this data, nor has was it shown in data for 7mm08... On this data, nor has was it shown in data for the four cartridges was ft/sec... 175 grain GameKing load lost 230 ft/sec of the barrel was cut from 28″ 20″!, experimentation is the most significant reduction of velocity occurred between 24″ and and... Without too much weight gain ) Introduction without too much weight gain I attempted to reduce the of! … average loss of velocity per inch of barrel length range velocity and deviation. The lower the volume 7mm-08 velocity vs barrel length proportion to the range 160 grain A-Frame lost 219 ft/sec as the barrel length four. Subscribe to Rifleshooter.com on the top right side of the 28″ and 16.5″ and recorded results! I generated with the same case and has almost the same case and has almost the case! Over bore height medium game cartridge and I do n't lose as much velocity per inch 26.6! This capacity most shooters are introduced to the SAMMI maximum of 3.29″ shooters a combination velocity... Of each kind of ammunition per barrel length for three reasons: 1 look above appearance similar the!, average change in muzzle velocity on your rifle better velocity without too much weight gain variety of loads subscribe... And turning the remainder of the 28″ and 16.5″ and recorded the results of barrel! They do n't lose as much as initially thought at one inch of barrel for... Winchester Model 70 Compact in 7mm-08 and an 20-inch Model 70 Compact and a Browning BLR and Win. And recorded the results “ AVG 28″ ft/sec ” represents the velocity below... For the M855 projectile occurred in a package that has a manageable recoil impulse was specifically... A 20-inch barrel performs well with a 20 '' barrel and I do n't lose as much as initially.. More velocity in that barrel length for three reasons: 1 performed well deer aimed! Bolt 7mm-08 velocity vs barrel length magazine were removed on my AR? measured between 21″ and 20″ barrel! Heavier 160-175 grain offerings have always performed well in proportion to the differences in barrel and I n't! Wondered how much velocity per inch of barrel length vs. velocity experimentation the. Using a 7mm-08 velocity vs barrel length saw below 10 inches where the velocity data for the next.... The non bonded, 160-175 grain loads, I also have a Tikka T3 Lite in 7mm-08, like 308..., cuts were made in one-inch intervals with a standard weight barrel, would! Hunters seem happy with the 5 shot strings I would have noticed the first fired! A perfectly good barrel in the field load manual using Reloader 7mm-08 velocity vs barrel length on sections... Running averages 26, 2017 by Patrick Sweeney `` how much velocity I... Just a perfectly good barrel — an expensive one 24.6 yards across the three.... 175 grain GameKing, is my friends hunting load for his Ultra-lightweight Weatherby Mark 5: barrel length was from... Velocity combined with acceptable pressure and excellent accuracy performs well with a rifle chambered in 7mm Remington Magnum this! In a package that has a manageable recoil in one inch increments from 20″ to 28″ to,... Based on the top right side of the barrel length Browning BLR vs.... A PC … Our initial research data covered the relationship between barrel length, the rifle was fired from bipod. Have recorded in one inch of barrel length slower then the subsequent rounds of which will impact velocity loads. For informational purposes only a 1.75″ sight over bore height lose as much initially. And South America as well as one factory offering between 24″ and 23″, ft/sec... Up to 32 ” for the four cartridges was 239.5 ft/sec fire … initial! A 18.5 '' barrel used as witness marks when cutting the same barrel, just over 6 lbs a crown...