March 4th, 2018

Valkyrie Velocity: Barrel Cut-Down Test with 60, 75, 90 grainers

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMK

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMKVelocity vs. barrel length — How much speed will I sacrifice with a shorter barrel? Hunters and competition shooters often ask that. Today we DO have solid answers to that question for many cartridge types thanks to Rifleshooter.com.

Rifleshooter.com has conducted a series of barrel cut-down tests for many popular chamberings: .223 Rem, 6mm Creedmoor, .243 Win, 6.5 Creedmoor, .308 Win, .300 Win Mag, .338 Lapua Magnum and more. And recently Rifleshooter.com added the new .224 Valkyrie cartridge to the list, cutting a 28″ Shilen barrel down to 16.5″ in one-inch increments. Rifleshooter.com measured the .224 Valkyrie’s velocities at each barrel length with four different types of factory ammo.

For its .224 Valkyrie test, RifleShooter.com sourced a Shilen Match Barrel and fitted it to a Rem 700 short action employing a one-piece PT&G bolt with the required .440″ (SPC-sized) bolt-face. The barreled action rides in a MDT LSS-XL Gen 2 Chassis.

READ .224 Valkyrie Barrel Cut-Down Test on Rifleshooter.com »

Bill, Rifleshooter.com’s Editor, explained his test procedure:

“I gathered four different types of factory Federal 224 Valkyrie ammunition, the 90gr Sierra MatchKing (SMK), 90gr Fusion soft point (SP) (referred to a Fusion MSR), 75gr Total Metal Jacket (TMJ) and 60gr Nosler Ballistic Tip Varmint (NBT). After a brief barrel break in and zero, I fired 5 rounds of each cartridge at each barrel length (except the 75 TMJ, I fired 4 rounds at each barrel length due to limited resources). I recorded the average muzzle velocity and standard deviation for each ammunition and barrel length combination and cut the barrel back 1 inch and repeated the process. I recorded barrel lengths from 28″ to 16.5″ (I try to save these barrels as finished 16″ tubes so they don’t go to waste).”

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMK

The Heavy Bullet 90gr Ammo Lost about 21 FPS per Inch
How did the test turn out? You’ll find all the results summarized in helpful tables with inch-by-inch velocity and SD numbers. For the two, 90gr ammo samples, results were similar. The 90gr SMK ammo started at 2782 fps (28″), finishing at 2541 fps (16.5″). That’s a loss of 241 fps, or 20.96 fps average per inch of length. The ammo loaded with 90gr Fusion SPs started at 2797 fps (28″) and ended at 2561 fps (16.5″), a drop of 236 fps. That’s 20.5 fps loss per inch. NOTE: Ambient temperature during the test was 45° F. You could expect the overall velocities to be a bit higher during hotter summer months.

See 90gr SMK Velocity/Length Test Chart | See 90gr Fusion SP Velocity/Length Test Chart

.224 Valkyrie Velocity Cut-Down Test

With a the smaller bullets, the effect was even more dramatic. As you’d expect they started out faster. The ammo with 60gr Nosler Ballistic Tips (NBT), a good choice for varminters, started at 3395 fps (28″), and declined to 3065 fps (16.5), a total velocity drop of 330 fps. Average velocity loss was 28.7 fps per inch of barrel length. Rifleshooter.com also tested Federal 75gr TMJ ammo.

About the .224 Valkyrie Cartridge

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMK

The new .224 Valkyrie was introduced late last year as a Hot Rod cartridge that will work in AR15s. Designed to rival the .22 Nosler while still running well in ARs, the new .224 Valkyrie offers excellent long-range performance when loaded with modern, high-BC bullets. We expect some bolt-action PRS shooters might adopt the .224 Valkyrie. Why? Reduced recoil. With the 90gr SMK, the .224 Valkyrie offers ballistics similar to the 6.5 Creedmoor but with significantly less felt recoil. Check out this chart from Federal showing comparative recoil levels:

.224 Valkyrie Federal Rifleshooter.com cut-down barrel

.224 Valkyrie vs. .22-250 Remington
The Social Regressive explains: “There are two key reasons why the 224 Valkyrie is unique and desirable. First, it is specifically designed to fit the limitations of the AR-15 platform. It does so even when loaded with gigantic bullets, like the 90-grain SMK that Federal announced. .22-250 Rem is too long and too fat to work in the AR-15 platform; it needs an AR-10 bolt and magazine.”

Image from Social Regressive .224 Valkyrie Youtube Video.

The new .224 Valkyrie is basically a 6.8 SPC case necked down to .22-caliber. You can use your existing AR15 lower, but you will need a dedicated .224-Valkyrie upper, or at the minimum a new barrel, modified bolt with proper bolt face, and 6.8-compliant mags.

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip No Comments »
September 13th, 2017

How Velocity Changes with Barrel Length — .223 Rem Test Results

.223 Rem Cut-Down Test barrel UMC m855

Most of us own a .223 Rem rifle. Now, thanks to our friends at Rifleshooter.com we can assess exactly how velocity changes with barrel length for this popular cartridge.

Rifleshooter.com performed an interesting test, cutting the barrel of a .223 Rem rifle from 26″ all the way down to 16.5″. The cuts were made in one-inch intervals with a rotary saw. At each cut length, velocity was measured with a Magnetospeed chronograph. To make the test even more interesting, four different types of .223 Rem/5.56 ammo were chron’d at each barrel length.

READ RifleShooter.com 5.56/.223 Barrel Cut-Down Test Article.

Test Barrel Lost 25.34 FPS Per Inch (.223 Rem Chambering)
How much velocity do you think was lost, on average, for each 1″ reduction in barrel length? The answer may surprise you. The average speed loss of the four types of .223/5.56 ammo, with a 9.5″ shortening of barrel length, was 240.75 fps total (from start to finish). That works out to an average loss of 25.34 fps per inch. (See inch-by-inch data HERE.)

5.56/.223 Barrel Cut-Down Speed Test 26″ to 16.5″ Start FPS at 26″ End FPS at 16.5″ Total Loss Average Loss Per Inch
UMC .223 55gr 3182* 2968 214 22.5 FPS
Federal M193 55gr 3431 3187 244 25.7 FPS
Win m855 62gr 3280 2992 288 30.3 FPS
Blk Hills .223 68gr 2849 2632 217 22.8 FPS

*There may have been an error. The 25″ velocity was higher at 3221 fps.

Rifleshooter.com observed: “Cutting the barrel from 26″ to 16.5″ resulted in a velocity reduction of 214 ft/sec with the UMC 223 55-grain cartridge, 244 ft/sec with the Federal M-193 cartridge, 288 ft/sec with the Winchester M855 cartridge and 217 ft/sec with the Back Hills 223 68-grain match cartridge.”

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. Average velocity and standard deviation were logged for each round. Once data was gathered for each cartridge at a given barrel length, the rifle was cleared and the bolt was removed. The barrel was cut off using a cold saw. The test protocol was repeated for the next length. Temperature was 45.7° F.”

CLICK HERE to Read the Rifleshooter.com Test. This includes detailed charts with inch-by-inch velocity numbers.

Much Different Results with 6mmBR and a Longer Barrel
The results from Rifleshooter.com’s .223/5.56 test are quite different than the results we recorded some years ago with a barrel chambered for the 6mmBR cartridge. When we cut our 6mmBR barrel down from 33″ to 28″ we only lost about 8 FPS per inch. Obviously this is a different cartridge type, but also our 6mmBR barrel end length was longer than Rifleshooter.com’s .223 Rem start length. Velocity loss may be more extreme with shorter barrel lengths.

Permalink Gunsmithing, Reloading 3 Comments »
March 7th, 2017

.338 Lapua Magnum Barrel Cut-Down Velocity Test

.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com
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″.

READ FULL .338 Lapua Magnum Barrel Cut-down Velocity TEST >>

The .338 Lapua Magnum is a jumbo-sized cartridge, that’s for sure…
.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com

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.”

.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com

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.

READ .338 LM Barrel Cut-down FULL TEST REPORT >>>

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip 4 Comments »
March 28th, 2016

6.5 Creedmoor — Barrel Cut-Down Velocity Tests

Rifleshooter.com 6.5 Creedmoor cut-down test

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.

CLICK HERE to SEE All Velocity Values at All Barrel Lengths

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.

Read Full Story with All Test Results at Rifleshooter.com

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.

Rifleshooter.com 6.5 Creedmoor cut-down test

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 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 6.5 mm 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.

6.5 Creedmoor Rifleshooter.com velocity barrel cut cut-down test saw blade

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.”

Permalink Gunsmithing, Tactical, Tech Tip 2 Comments »