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 3 Comments »
March 7th, 2017

Learn Long-Range Skills at Williamsport 1K Benchrest School

Williamsport 1000 yard Benchrest School
Sebastian Reist photo.

There are still some openings left for the June 2017 Williamsport 1000 Yard Benchrest School. “If you have been considering long range competition, come on out and learn from some of the top shooters in the game. This school will take years off of the typical learning curve.”– Eric Wolfgang, Original PA 1000 Yard Benchrest Club Secretary/Statistician.

CLICK HERE for 2017 Williamsport 1K Benchrest School Application Form (MS Word Doc)

Williamsport Shooting School Benchrest 1000 Yard

Praise from a 1K Benchrest School Grad
Here’s a testimonial from a recent graduate: “I can attest to the knowledge that you gain. I went last year and loved it. Have renewed my membership in the Club and would love to go this year. I would love to take the course again. In the photo above I am in the back row, fourth from the right — sunglasses and blue shirt.” — Bob, Class of 2016

Williamsport benchrest schoolThe 10th Annual Williamsport 1000-Yard Benchrest School will be held Saturday June 3 and Sunday June 4, 2017. There are still a few slots available for this year’s session. Classes, taught by top 1K shooters, are held at the Original Pennsylvania 1000-Yard Benchrest Club Range, one of the best 1K ranges in the country. See photos at: www.PA1000yard.com

Participants will learn all aspects of long-range benchrest shooting from some of the most skilled marksmen in the country. Much time is spent at the loading bench and on the firing line. Classes cover load development, precision reloading, bench skills, and target analysis. You don’t even need guns and ammo — all equipment and ammunition will be provided.

School instructors tell us: “This year’s benchrest school will be a 2-day weekend event. (There is also an optional ‘Meet and Greet’ gathering Friday evening). The school is a beginner class designed to teach the fundamental skills needed to be competitive at at 600 and 1000 yards. Saturday will be spent in class covering a range of topics including reloading ‘dos and don’ts’, load development and equipment handling. Sunday we will shoot an actual match to see what you’ve learned.”

Cost for the class is $375.00 including lunches on Sat/Sun and dinner on Saturday. Don’t hesitate if you want to attend the 2017 school. For more INFO email Ray McKinsey, Joe Saltalamachia, or Eric Wolfgang via this Club Contact Page.

Watch Williamsport Benchrest School Slideshow:
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This slideshow was produced by Sebastian Reist an alumnus of the 2009 Williamsport 1000-yard BR school. SEE: www.sreistphotography.com.
Permalink Competition, News 1 Comment »
March 7th, 2017

Six-Five Smackdown: The .260 Remington vs. 6.5×55 Swedish

6.5x55 SE, 6.5 Swedish 6.6x55mm .260 Rem Remington Laurie Holland comparison

The .260 Remington and the 6.5×55 Swedish (aka 6,5x55mm SE) are both very popular cartridges with hunters and target shooters. The 6.5×55 has a long military heritage and a great record as a hunting round. The .260 Rem, essentially a .308 Win necked down to .264 caliber, is a more recent cartridge, but it grows in popularity every year, being one of the top cartridges for tactical/practical competitions. It offers better ballistics and less recoil than the parent .308 Win cartridge. In our Shooter’s Forum, respected UK gun writer Laurie Holland provided a good summary of the differences between the two chamberings. Laurie writes:

Remington 260 CartridgeThe 6.5×55 case has 6 or 7% more capacity than the .260s, even more in practice when both are loaded to standard COALs with heavy bullets, which sees them having to seated very deep in the .260 Rem using up quite a lot of powder capacity. So loaded up for reasonable pressures in modern actions, the 6.5×55 will give a bit more performance.

The issue for many is what action length is available or wanted, the 6.5×55 requiring a long action. So sniper rifle / tactical rifle competitors will go for the .260 Rem with the option of the many good short-bolt-throw designs around with detachable box magazines (DBMs). If a bit more performance is needed, the .260 AI (photo right) can yield another 100-150 fps velocity, depending on bullet weight.

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Permalink - Articles, Reloading, Tech Tip 8 Comments »