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April 18th, 2023
Rifleshooter.com does some great original research — providing “hard data” you can’t find anywhere else. Here are the eye-opening results of Rifleshooter.com’s 6.5 Creedmoor barrel cut-down test. You may be surprised at the results. Read on…
What do you get when you cut a 6.5 Creedmoor-chambered barrel down to just over 16 inches? A lot more velocity than you might think. Our friends at Rifleshooter.com conducted a remarkable barrel cut-down test with 6.5 Creedmoor test rifle, shortening the barrel from 27 to 16.1 inches in one-inch increments. Surprisingly, with a 142gr Sierra MK, the total velocity loss (as measured with a Magnetospeed) was just 158 FPS, an average of 14.4 FPS per inch of barrel length. With the lighter 120gr A-Max bullet, the total velocity loss was 233 FPS, or 21.8 FPS average loss per inch of barrel.
To perform this velocity test, our friend Bill, Rifleshooter.com’s editor, built up a 6.5 Creedmoor rifle using a Remington Model 7 action, 1:8″ twist Green Mountain CM barrel, and MDT LSS Chassis, all obtained from Brownells.com.
Test Procedure
Five (5) rounds of each type of cartridge were fired at each barrel length and the velocity data was recorded with a MagnetoSpeed V3 barrel-mounted chronograph. The rifle was then cleared and the barrel was cut back one inch at a time from 27″ to just over 16″. NOTE: During this winter test, the air temperature was a very chilly 23° F. One would expect higher velocities across the board had the outside temperature been higher.
The photo below shows how the barrel was cut down, inch-by-inch, using a rotary saw. The barrel was pre-scored at inch intervals. As the main purpose of the test was to measure velocity (not accuracy) the testers did not attempt to create perfect crowns.
6.5 Creedmoor vs. Other Mid-Sized 6.5mm Cartridges
The 6.5 Creedmoor is a very popular cartridge with the tactical and PRS crowd. This mid-size cartridge offers good ballistics, with less recoil than a .308 Winchester. There’s an excellent selection of 6.5mm bullets, and many good powder choices for this cartridge. When compared to the very accurate 6.5×47 Lapua cartridge, the 6.5 Creedmoor offers similar performance with less expensive brass. For a tactical shooter who must sometimes leave brass on the ground, brass cost is a factor to consider. Here’s a selection of various 6.5mm mid-sized cartridges. Left to right are: 6.5 Grendel, 6.5×47 Lapua, 6.5 Creedmoor with 120gr A-Max, 6.5 Creedmoor with 142gr Sierra MK, and .260 Remington.
When asked to compare the 6.5 Creedmoor to the 6.5×47 Lapua, Rifleshooter.com’s editor stated: “If you don’t hand load, or are new to precision rifle shooting, get a 6.5 Creedmoor. If you shoot a lot, reload, have more disposable income, and like more esoteric cartridges, get a 6.5×47 Lapua. I am a big fan of the 6.5×47 Lapua. In my personal experience, the 6.5×47 Lapua seems to be slightly more accurate than the 6.5 Creedmoor. I attribute this to the quality of Lapua brass.” Now that Lapua offers 6.5 Creedmoor brass with small primer pockets, the 6.5 Creedmoor is even more attractive.
The creator of Rifleshooter.com also operates a Custom Rifle Building enterprise and gun shop in Long Island, New York: 782 Custom Guns Ltd.. He tells us: “We offer an unparalleled level of gunsmith machine shop services in the Long Island region. From precision rifles (USMC M40A3/A5/A6 XM3 clones) to customized Remington 870 and Mossberg 590 shotguns, and customized 1911s, chances are if you can dream it, we can build it!”
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August 12th, 2018
Rifleshooter.com does some great original research — providing “hard data” you can’t find anywhere else. Here are the eye-opening results of Rifleshooter.com’s 6.5 Creedmoor barrel cut-down test. You may be surprised at the results. Read on…
What do you get when you cut a 6.5 Creedmoor-chambered barrel down to just over 16 inches? A lot more velocity than you might think. Our friends at Rifleshooter.com recently did a barrel cut-down test with 6.5 Creedmoor test rifle, shortening the barrel from 27 to 16.1 inches in one-inch increments. Surprisingly, with a 142gr Sierra MK, the total velocity loss (as measured with a Magnetospeed) was just 158 FPS, an average of 14.4 FPS per inch of barrel length. With the lighter 120gr A-Max bullet, the total velocity loss was 233 FPS, or 21.8 FPS average loss per inch of barrel.
To perform this velocity test, our friend Bill, Rifleshooter.com’s editor, built up a 6.5 Creedmoor rifle using a Remington Model 7 action, 1:8″ twist Green Mountain CM barrel, and MDT LSS Chassis, all obtained from Brownells.com.
Test Procedure
Five (5) rounds of each type of cartridge were fired at each barrel length and the velocity data was recorded with a MagnetoSpeed V3 barrel-mounted chronograph. The rifle was then cleared and the barrel was cut back one inch at a time from 27″ to just over 16″. NOTE: During this winter test, the air temperature was a very chilly 23° F. One would expect higher velocities across the board had the outside temperature been higher.
The photo below shows how the barrel was cut down, inch-by-inch, using a rotary saw. The barrel was pre-scored at inch intervals. As the main purpose of the test was to measure velocity (not accuracy) the testers did not attempt to create perfect crowns.
6.5 Creedmoor vs. Other Mid-Sized 6.5mm Cartridges
The 6.5 Creedmoor is a very popular cartridge with the tactical and PRS crowd. This mid-size cartridge offers good ballistics, with less recoil than a .308 Winchester. There’s an excellent selection of 6.5mm bullets, and many good powder choices for this cartridge. When compared to the very accurate 6.5×47 Lapua cartridge, the 6.5 Creedmoor offers similar performance with less expensive brass. For a tactical shooter who must sometimes leave brass on the ground, brass cost is a factor to consider. Here’s a selection of various 6.5mm mid-sized cartridges. Left to right are: 6.5 Grendel, 6.5×47 Lapua, 6.5 Creedmoor with 120gr A-Max, 6.5 Creedmoor with 142gr Sierra MK, and .260 Remington.
When asked to compare the 6.5 Creedmoor to the 6.5×47 Lapua, Rifleshooter.com’s editor stated: “If you don’t hand load, or are new to precision rifle shooting, get a 6.5 Creedmoor. If you shoot a lot, reload, have more disposable income, and like more esoteric cartridges, get a 6.5×47 Lapua. I am a big fan of the 6.5×47 Lapua. In my personal experience, the 6.5×47 Lapua seems to be slightly more accurate than the 6.5 Creedmoor. I attribute this to the quality of Lapua brass.” Now that Lapua offers 6.5 Creedmoor brass with small primer pockets, the 6.5 Creedmoor is even more attractive.
The creator of Rifleshooter.com also operates a Custom Rifle Building enterprise and gun shop in Long Island, New York: 782 Custom Guns Ltd.. He tells us: “We offer an unparalleled level of gunsmith machine shop services in the Long Island region. From precision rifles (USMC M40A3/A5/A6 XM3 clones) to customized Remington 870 and Mossberg 590 shotguns, and customized 1911s, chances are if you can dream it, we can build it!”
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March 7th, 2017
Shooters contemplating purchase of a .338 LM rifle often ask: “What length barrel should I get?” Rifleshooter.com recently performed a test that provides interesting answers…
Our friends at RifleShooter.com like to slice and dice — barrels that is. They have done barrel length cut-down tests for popular calibers like the .223 Rem, 6.5 Creedmoor, and .308 Winchester. But now they’ve tackled something way bigger — the .338 Lapua Magnum, a true “Big Boomer”. Starting with a beefy 30″-long Pac-Nor Barrel, RifleShooter.com chopped the tube down in one-inch increments all the way down to 17 inches (that’s 14 different lengths). At each new (shorter) barrel length, velocity was measured with a MagnetoSpeed chronograph using two different loads, 250gr SMKs with H4831sc and 300gr SMKs with Retumbo. Four shots were fired at each length with each load, a total of 112 rounds.
Load #1: 250gr Sierra MK, Lapua brass, CCI #250 primer, H4831SC, OAL 3.720″.
Load #2: 300gr Sierra MK, Lapua brass, Win WLRM primer, Retumbo, OAL 3.720″.
The .338 Lapua Magnum is a jumbo-sized cartridge, that’s for sure…
Donor Barrel Sacrificed for Science
Rifleshooter.com’s Editor explains: “Brandon from Precision Addiction offered to send us his .338 barrel for our .338 Lapua Mag test. I took him up on his offer and he sent me his used Pac-Nor chrome-moly barrel with about 600 rounds though it. This thing was a beast! A heavy 1.350″ shank that ran straight for 6″, until tapering to 1″ at 30″ in length.”
Results Summary
.338 Lapua Magnum with 250gr Sierra MatchKings
After shortening the barrel from 30″ to 17″, total velocity reduction for the 250-grainers was 395 FPS, an average loss of 30.4 FPS per 1″ cut. The amount of velocity loss per inch rose as the barrel got shorter, with the biggest speed reduction, a loss of 55 FPS, coming with the cut from 18″ to 17″.
Start Velocity: 2942 FPS | End Velocity: 2547 FPS | Average Loss Per Inch: 30.4 FPS
.338 Lapua Magnum with 300gr Sierra MatchKings
Shooting the 300-grainers, total velocity reduction was 341 fps, an average of 26.2 FPS loss per 1″ cut (30″ down to 17″). However, the speed actually increased with the first cut from 30 inches to 29 inches. The tester noted: “The 300 SMK load showed a slight increase from 30″ to 29″. I’ve recorded this in other tests and it seems to be more common with a heavier load. I suspect it is primarily due to the small sample sizes being used along with the relative proximity of muzzle velocities in adjacent lengths.”
Start Velocity: 2833 FPS | End Velocity: 2492 FPS | Average Loss Per Inch: 26.2 FPS*
*Velocity rose with first cut. Velocities ranged from 2,871 FPS (29″) to 2,492 FPS (17″) for a total velocity loss of 341 FPS.
RifleShooter.com crunched the velocity numbers in some interesting ways. For example they analyzed rate of velocity loss, concluding that: “after the initial rate change, the rate of the change in velocity is fairly consistent.” (View Rate of Change Graph)
How Velocity Loss Alters Long-Range Ballistics
The testers wanted to determine how the velocity reductions “affect our ability to hit targets downrange”. So, Rifleshooter.com plotted changes in elevation and wind drift at all barrel lengths. This revealed something interesting — drift increased significantly below 26″ barrel length: “Above 26″ things look pretty good, below 22″ they change quickly.”
We highly recommend you read the whole story. Rifleshooter.com put in serious time and effort, resulting in solid, thought-provoking results. The data is presented in multiple tables and graphs, revealing inch-by-inch velocities, change “deltas”, and SDs at each length.
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