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August 15th, 2024

Blueprinting and Truing Remington 700 Action — Expert Methods

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizingYou may have heard the phrase “blueprinting an action”, but do you know what that really means? Do you know what operations are done to an action during the blueprinting process? To help you understand, gunsmith Bill Marr of RifleShooter.com has created a helpful article showing a Rem 700 blueprinting job start to finish. This article spotlights how the procedures can be done with manual tools. Bill, who runs 782 Custom Gunworks Ltd., can also perform many of these operations with modern automated machinery. In fact, Bill has written a follow-up article on Truing a Rem 700 receiver with a Lathe.

READ Full Action Blueprinting Article HERE with 30+ Photos »

READ Blueprinting Rem 700 Action with Lathe Article HERE »

Bill explains: “Blue-printing, or truing a rifle action, ensures the receiver face, threads, lugs, bolt lugs, and bolt face are square to the center line of the receiver.” In Bill’s informative article, Bill shows how he blueprints a Remington 700 short action receiver with .308 Win bolt face. He covers the following procedures step by step:

Action Disassembly
Ream Minor Diameter of Receiver Threads
Square the Receiver Lugs
Square the Face of the Receiver
Lap the Bolt Lugs
Square the Bolt Face

Bill employed a variety of tools from Brownells to complete the blueprinting job, including: Remington 700 Armorer’s Kit; Manson Receiver Accurizing Kit; Bolt Lapping Kit; Bolt Face Truing Tool; Manson Receiver Ring Facing Cutter; Multi-Vise with Jaw Pads; Silicone Carbide Abrasive; and Do-Drill Cutting Oil.

Highlights from the Rifleshooter.com article:

1. Chasing the Threads

We use the bushings to guide the receiver tap. This chases the threads and ensures they are square.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

2. Truing the Receiver Face

Using the receiver facing tool, the front of the receiver is trued. The tool is placed over the tap and turned by hand. We used Do Drill to lubricate it.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

3. Lapping the Lugs

The bolt lapping tool screws into the front of the action and applies rearward pressure on the bolt face. A little bit of lapping compound is placed on the front of the receiver lugs. The bolt handle is then raised and lowered repeatedly. Note — it is critical that we do not get any lapping compound on any other surfaces.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

4. Truing the Bolt Face

On this bolt, the central part of the bolt face was low. After the truing operation, this Rem 700 bolt face is now completely square to the action.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

IMPORTANT: Rifleshooter.com states: “This article highlights our project and is presented for information purposes only. This provides an overview of the process and should not be attempted without the guidance and supervision of an experienced gunsmith“.

Permalink Gear Review, Gunsmithing, Tech Tip No Comments »
January 9th, 2024

How to Blueprint a Rem 700 Action — RifleShooter.com Report

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizingYou may have heard the phrase “blueprinting an action”, but do you know what that really means? Do you know what operations are done to an action during the blueprinting process? To help you understand, gunsmith Bill Marr of RifleShooter.com has created a helpful article showing a Rem 700 blueprinting job start to finish. This article spotlights how the procedures can be done with manual tools. Bill, who runs 782 Custom Gunworks Ltd., can also perform many of these operations with modern automated machinery. In fact, Bill has written a follow-up article on Truing a Rem 700 receiver with a Lathe.

READ Full Action Blueprinting Article HERE with 30+ Photos »

Bill explains: “Blue-printing, or truing a rifle action, ensures the receiver face, threads, lugs, bolt lugs, and bolt face are square to the center line of the receiver.” In Bill’s informative article, Bill shows how he blueprints a Remington 700 short action receiver with .308 Win bolt face. He covers the following procedures step by step:

Action Disassembly
Ream Minor Diameter of Receiver Threads
Square the Receiver Lugs
Square the Face of the Receiver
Lap the Bolt Lugs
Square the Bolt Face

Bill employed a variety of tools from Brownells to complete the blueprinting job, including: Remington 700 Armorer’s Kit; Manson Receiver Accurizing Kit; Bolt Lapping Kit; Bolt Face Truing Tool; Manson Receiver Ring Facing Cutter; Multi-Vise with Jaw Pads; Silicone Carbide Abrasive; and Do-Drill Cutting Oil.

Highlights from the Rifleshooter.com article:

1. Chasing the Threads

We use the bushings to guide the receiver tap. This chases the threads and ensures they are square.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

2. Truing the Receiver Face

Using the receiver facing tool, the front of the receiver is trued. The tool is placed over the tap and turned by hand. We used Do Drill to lubricate it.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

3. Lapping the Lugs

The bolt lapping tool screws into the front of the action and applies rearward pressure on the bolt face. A little bit of lapping compound is placed on the front of the receiver lugs. The bolt handle is then raised and lowered repeatedly. Note — it is critical that we do not get any lapping compound on any other surfaces.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

4. Truing the Bolt Face

On this bolt, the central part of the bolt face was low. After the truing operation, this Rem 700 bolt face is now completely square to the action.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

READ Blueprinting Rem 700 Action with Lathe Article HERE »

IMPORTANT: Rifleshooter.com states: “This article highlights our project and is presented for information purposes only. This provides an overview of the process and should not be attempted without the guidance and supervision of an experienced gunsmith“.

Permalink Gear Review, Gunsmithing, Tech Tip 3 Comments »
August 4th, 2022

Blueprinting Rem 700 Action — “How-To” with Rifleshooter.com

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizingYou may have heard the phrase “blueprinting an action”, but do you know what that really means? Do you know what operations are done to an action during the blueprinting process? To help you understand, gunsmith Bill Marr of RifleShooter.com has created a helpful article showing a Rem 700 blueprinting job start to finish. This article spotlights how the procedures can be done with manual tools. Bill, who runs 782 Custom Gunworks Ltd., can also perform many of these operations with modern automated machinery. In fact, Bill has written a follow-up article on Truing a Rem 700 receiver with a Lathe.

READ Full Action Blueprinting Article HERE with 30+ Photos »

Bill explains: “Blue-printing, or truing a rifle action, ensures the receiver face, threads, lugs, bolt lugs, and bolt face are square to the center line of the receiver.” In Bill’s informative article, Bill shows how he blueprints a Remington 700 short action receiver with .308 Win bolt face. He covers the following procedures step by step:

Action Disassembly
Ream Minor Diameter of Receiver Threads
Square the Receiver Lugs
Square the Face of the Receiver
Lap the Bolt Lugs
Square the Bolt Face

Bill employed a variety of tools from Brownells to complete the blueprinting job, including: Remington 700 Armorer’s Kit; Manson Receiver Accurizing Kit; Bolt Lapping Kit; Bolt Face Truing Tool; Manson Receiver Ring Facing Cutter; Multi-Vise with Jaw Pads; Silicone Carbide Abrasive; and Do-Drill Cutting Oil.

Highlights from the Rifleshooter.com article:

1. Chasing the Threads

We use the bushings to guide the receiver tap. This chases the threads and ensures they are square.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

2. Truing the Receiver Face

Using the receiver facing tool, the front of the receiver is trued. The tool is placed over the tap and turned by hand. We used Do Drill to lubricate it.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

3. Lapping the Lugs

The bolt lapping tool screws into the front of the action and applies rearward pressure on the bolt face. A little bit of lapping compound is placed on the front of the receiver lugs. The bolt handle is then raised and lowered repeatedly. Note — it is critical that we do not get any lapping compound on any other surfaces.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

4. Truing the Bolt Face

On this bolt, the central part of the bolt face was low. After the truing operation, this Rem 700 bolt face is now completely square to the action.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

READ Blueprinting Rem 700 Action with Lathe Article HERE »

IMPORTANT: Rifleshooter.com states: “This article highlights our project and is presented for information purposes only. This provides an overview of the process and should not be attempted without the guidance and supervision of an experienced gunsmith“.

Permalink - Videos, Gear Review, Gunsmithing, Tech Tip 1 Comment »
January 16th, 2022

Sunday Gunday: Remington 700 — History, X-Ray, Blueprinting

remington 700 bolt-action rifle gunday X-Ray Blueprinting

For today’s Sunday GunDay story, we look at the legendary Remington 700, perhaps the most popular American bolt-action rifle of all time. After covering the history of the Rem 700 rifle, we provide an inside look at the Rem 700 through a series of cutaway animations. Then we explain how gunsmiths can enhance a Remington 700 action through “blueprinting” procedures.

Remington 700 Origins and History

remington 700 manualAfter World War II, Remington Arms engineer Mike Walker began designing lower-cost alternatives to the Model 30, which resulted in the Model 721. These used a cylindrical receiver produced from cylindrical bar stock that could be turned on a lathe, rather than machined in a series of milling operations, which significantly reduced the cost of production. Further developments of the basic 721 action under the direction of Walker produced the Model 722 and Model 725, and ultimately in 1962, the Model 700.

Walker sought to increase the accuracy of the rifles, by utilizing tight tolerances in the chamber and bore, a short leade, and a very fast lock time. Like the earlier 721, the Remington 700 action was designed for mass production. Remington initially produced two variants of the Model 700, the ADL and BDL, in both long- and short-action versions. In 1969, Remington introduced upgrades for the rifle, including a longer rear bolt shroud, a jeweled bolt, and improved stock finishing. Four years later, production of left-handed Rem 700s began, to compete with the Savage Model 110, at that time the only major American-made left-bolt rifle.

Other Rem 700 versions include the titanium receiver 700ti, the 700 SPS (which replaced the ADL in 2005), and the CDL model. In addition to its development as a hunting rifle, the Model 700 also provided the basis for military and police sniper rifles, starting with the M40 rifle in 1966, which was initially ordered by the U.S. Marine Corps. The U.S. Army adopted the M24 Sniper Weapon System in 1986.

remington 700 bolt-action rifle gunday X-Ray Blueprinting
The Remington 700 is sold in both short action and long action variants. This photo is from the Big ED YouTube video comparing the two action lengths.

The Remington 700 is a manually-operated bolt action with two forward dual-opposed lugs. The bolt face is recessed, fully enclosing the base of the cartridge, The extractor is a C-clip sitting within the bolt face. The ejector is a plunger on the bolt face actuated by a coil spring. The bolt is of 3-piece construction, brazed together (head, body and bolt handle). The receiver is milled from round cross-section steel.

Chassis Systems for Remington 700s

With the popularity of the Remington 700 series rifles, and the availability of Rem 700 barreled actions by themselves, many companies have created after-market chassis systems. This GunMan YouTube Video reviews five modern chassis systems configured for Remington 700 barreled actions. Modular chassis systems have become particularly popular with PRS/NRL competitors.

Rem 700 Cutaway Video Shows Components + Operation

Ever wish you could look inside your rifle, to see how the trigger and fire-control system work? Well now that is possible with the magic of 3D computer graphics. Modern software allows detailed “cutaway” side-views (see below), as well as 3D views with 360° rotation. The software can also provide X-Ray-type views into the gun’s internals — as you can see above. And computer animation can show the complete firing process from trigger pull to chambering of the next round.

3d firearms modeling gun CGI software encylopedia gun disassembly

READERS — Do take the time to watch the video! This Rem 700 animation is really outstanding! EVERY bolt-action shooter should watch this video all the way through.

The Model 700 series of bolt-action rifles have been manufactured by Remington Arms since 1962. All are based on basically the same centerfire bolt action. They are typically sold with an internal magazine depending on caliber, some of which have a floor-plate for quick-unloading, and some of which are “blind” (no floor-plate). The Model 700 is a development of the Remington 721 and 722 series of rifles, which were introduced in 1948.

3d firearms modeling gun CGI software encylopedia gun disassembly

The Remington 700 is a manually-operated bolt action with forward, dual opposed lugs. It features “Cock On Opening”, meaning the upward rotation of the bolt when the rifle is opened cocks the firing pin. A cam mechanism pushes the firing pin’s cocking piece backward. The bolt face is recessed, fully enclosing the base of the cartridge. The extractor is a C-clip sitting within the bolt face. The ejector is a plunger on the bolt face actuated by a coil spring. The bolt is of 3-piece construction, brazed together (head, body. and bolt handle). The receiver is milled from round cross-section steel.

Blueprinting Rem 700 Action — Making a Good Action Better

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizingYou may have heard the phrase “blueprinting an action”, but do you know what that really means? Do you know what operations are done to an action during the blueprinting process? To help you understand, gunsmith Bill Marr of RifleShooter.com has created a helpful article showing a Rem 700 blueprinting job start to finish. This article spotlights how the procedures can be done with manual tools. Bill, who runs 782 Custom Gunworks Ltd., can also perform many of these operations with modern automated machinery. In fact, Bill has written a follow-up article on Truing a Rem 700 receiver with a Lathe.

Bill explains: “Blue-printing, or truing a rifle action, ensures the receiver face, threads, lugs, bolt lugs, and bolt face are square to the center line of the receiver.” In Bill’s informative article, Bill shows how he blueprints a Remington 700 short action receiver with .308 Win bolt face. He covers the following procedures step by step:

Action Disassembly
Ream Minor Diameter of Receiver Threads
Square the Receiver Lugs
Square the Face of the Receiver
Lap the Bolt Lugs
Square the Bolt Face

Bill employed a variety of tools from Brownells to complete the blueprinting job, including: Remington 700 Armorer’s Kit; Manson Receiver Accurizing Kit; Bolt Lapping Kit; Bolt Face Truing Tool; Manson Receiver Ring Facing Cutter; Multi-Vise with Jaw Pads; Silicone Carbide Abrasive; and Do-Drill Cutting Oil.

1. Truing the Receiver Face

Using the receiver facing tool, the front of the receiver is trued. The tool is placed over the tap and turned by hand. We used Do Drill to lubricate it.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

2. Lapping the Lugs

The bolt lapping tool screws into the front of the action and applies rearward pressure on the bolt face. A little bit of lapping compound is placed on the front of the receiver lugs. The bolt handle is then raised and lowered repeatedly. Note — it is critical that we do not get any lapping compound on any other surfaces.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

3. Truing the Bolt Face

On this bolt, the central part of the bolt face was low. After the truing operation, this Rem 700 bolt face is now completely square to the action.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

READ Full Action Blueprinting Article HERE with 30+ Photos »

IMPORTANT: Rifleshooter.com states: “This article highlights our project and is presented for information purposes only. This provides an overview of the process and should not be attempted without the guidance and supervision of an experienced gunsmith“.

PT&G Pacific Tool Remington Rem 700 action accurizing

If you like the idea of a Blueprinted action, but do not have a good gunsmith nearby (or don’t want to wait many weeks), you can order high-grade blueprinted Remington 700 actions from Pacific Tool & Gauge starting at $637.99 (see above).

Permalink - Articles, - Videos, Gear Review, Gunsmithing, Tech Tip No Comments »
February 17th, 2021

How to Blueprint a Rem 700 Action — Rifleshooter.com Reveals

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizingYou may have heard the phrase “blueprinting an action”, but do you know what that really means? Do you know what operations are done to an action during the blueprinting process? To help you understand, gunsmith Bill Marr of RifleShooter.com has created a helpful article showing a Rem 700 blueprinting job start to finish. This article spotlights how the procedures can be done with manual tools. Bill, who runs 782 Custom Gunworks Ltd., can also perform many of these operations with modern automated machinery. In fact, Bill has written a follow-up article on Truing a Rem 700 receiver with a Lathe.

READ Full Action Blueprinting Article HERE with 30+ Photos »

Bill explains: “Blue-printing, or truing a rifle action, ensures the receiver face, threads, lugs, bolt lugs, and bolt face are square to the center line of the receiver.” In Bill’s informative article, Bill shows how he blueprints a Remington 700 short action receiver with .308 Win bolt face. He covers the following procedures step by step:

Action Disassembly
Ream Minor Diameter of Receiver Threads
Square the Receiver Lugs
Square the Face of the Receiver
Lap the Bolt Lugs
Square the Bolt Face

Bill employed a variety of tools from Brownells to complete the blueprinting job, including: Remington 700 Armorer’s Kit; Manson Receiver Accurizing Kit; Bolt Lapping Kit; Bolt Face Truing Tool; Manson Receiver Ring Facing Cutter; Multi-Vise with Jaw Pads; Silicone Carbide Abrasive; and Do-Drill Cutting Oil.

Highlights from the Rifleshooter.com article:

1. Chasing the Threads

We use the bushings to guide the receiver tap. This chases the threads and ensures they are square.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

2. Truing the Receiver Face

Using the receiver facing tool, the front of the receiver is trued. The tool is placed over the tap and turned by hand. We used Do Drill to lubricate it.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

3. Lapping the Lugs

The bolt lapping tool screws into the front of the action and applies rearward pressure on the bolt face. A little bit of lapping compound is placed on the front of the receiver lugs. The bolt handle is then raised and lowered repeatedly. Note — it is critical that we do not get any lapping compound on any other surfaces.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

4. Truing the Bolt Face

On this bolt, the central part of the bolt face was low. After the truing operation, this Rem 700 bolt face is now completely square to the action.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

READ Blueprinting Rem 700 Action with Lathe Article HERE »

IMPORTANT: Rifleshooter.com states: “This article highlights our project and is presented for information purposes only. This provides an overview of the process and should not be attempted without the guidance and supervision of an experienced gunsmith“.

Permalink - Articles, Gunsmithing, Tech Tip No Comments »
August 27th, 2019

Cutting .338 LM Barrel from 30″ to 17″ — Velocity Loss Revealed!

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

With Randy Wise’s recent record-setting ELR performance with a .338 Lapua Magnum Savage rifle, we thought our readers might be interested in a .338 LM velocity test conducted by our friend Bill Marr, Editor of Rifleshooter.com.

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

782 custom gunworks ltdA couple seasons back, Bill did a fascinating barrel cut-down test on a .338 Lapua Magnum rifle. Bill, a skilled gunsmith who runs 782 Custom Gunworks, cut down the barrel from 30″ to 17″ in one-inch increments. During the cut-down process, Marr measured velocities at each barrel length, shooting four rounds after each cut. As you’d expect, there was a huge change in velocity from long to short. Speeds were measured at the muzzle with a Magnetospeed barrel-mounted chronograph.

If you’re looking for max velocity with the .338 LM, go long. With 250-grain Sierra MK bullets, the peak velocity Bill measured was 2942 FPS at the full, 30-inch length. This decreased pretty steadily down to 2547 GPS at the shortest 17″ length. That’s an average decrease of 30.4 FPS per inch from 30″ to 17″.

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

Bill also tested 300-grain Sierra MatchKings. This is interesting because Randy Wise ran 300-grain bullets (Berger Hybrids) in a 26″ factory barrel for his ELR record. Peak velocity was 2833 FPS at 30″, 2799 FPS at 26″, and 2492 FPS at the shortest 17″ length. Interestingly, velocity at 29″ was higher than at 30″ for the 300-grainers. Bill notes: “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.”

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″.

.338 LM Barrel Cut-Down Test Results Summary

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

.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

(more…)

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip 3 Comments »
August 17th, 2019

Truing a Rem 700 Action — RifleShooter.com Shows the Process

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizingYou may have heard the phrase “blueprinting an action”, but do you know what that really means? Do you know what operations are done to an action during the blueprinting process? To help you understand, gunsmith Bill Marr of RifleShooter.com has created a helpful article showing a Rem 700 blueprinting job start to finish. This article spotlights how the procedures can be done with manual tools. Bill, who runs 782 Custom Gunworks Ltd., can also perform many of these operations with modern automated machinery. In fact, Bill has written a follow-up article on Truing a Rem 700 receiver with a Lathe.

READ Full Action Blueprinting Article HERE with 30+ Photos »

READ Blueprinting Rem 700 Action with Lathe Article HERE »

Bill explains: “Blue-printing, or truing a rifle action, ensures the receiver face, threads, lugs, bolt lugs, and bolt face are square to the center line of the receiver.” In Bill’s informative article, Bill shows how he blueprints a Remington 700 short action receiver with .308 Win bolt face. He covers the following procedures step by step:

Action Disassembly
Ream Minor Diameter of Receiver Threads
Square the Receiver Lugs
Square the Face of the Receiver
Lap the Bolt Lugs
Square the Bolt Face

Bill employed a variety of tools from Brownells to complete the blueprinting job, including: Remington 700 Armorer’s Kit; Manson Receiver Accurizing Kit; Bolt Lapping Kit; Bolt Face Truing Tool; Manson Receiver Ring Facing Cutter; Multi-Vise with Jaw Pads; Silicone Carbide Abrasive; and Do-Drill Cutting Oil.

Highlights from the Rifleshooter.com article:

1. Chasing the Threads

We use the bushings to guide the receiver tap. This chases the threads and ensures they are square.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

2. Truing the Receiver Face

Using the receiver facing tool, the front of the receiver is trued. The tool is placed over the tap and turned by hand. We used Do Drill to lubricate it.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

3. Lapping the Lugs

The bolt lapping tool screws into the front of the action and applies rearward pressure on the bolt face. A little bit of lapping compound is placed on the front of the receiver lugs. The bolt handle is then raised and lowered repeatedly. Note — it is critical that we do not get any lapping compound on any other surfaces.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

4. Truing the Bolt Face

On this bolt, the central part of the bolt face was low. After the truing operation, this Rem 700 bolt face is now completely square to the action.

Bill Marr Rifleshooter.com truing Remington Rem 700 action accurizing

IMPORTANT: Rifleshooter.com states: “This article highlights our project and is presented for information purposes only. This provides an overview of the process and should not be attempted without the guidance and supervision of an experienced gunsmith“.

Permalink - Articles, Gunsmithing, Tech Tip 2 Comments »
May 7th, 2019

6mm Creedmoor — How Many FPS Will a Shorter Barrel Cost You?

6mm 6.5 Creedmoor rifleshooter.com Bill Barr barrel length cut-down velocity test chronograph Magnetospeed chrono

Our friend Bill Marr of Rifleshooter.com has done it again — conducted a fascinating 6mm Creedmoor barrel cut-down test that reveals how velocity changes with barrel length. This time Bill started with a 24″ Proof Research stainless steel barrel on a Howa action. Bill says this was a well-used barrel, with over 1800 rounds through it. So, the velocities might be a bit different than a new barrel of similar length. Bill cut the barrel down in one-inch increments. Here are some results from the test:

24″ Velocity: 2893 FPS | 20″ Velocity: 2755 FPS | 16.1″ Velocity: 2598 FPS

CLICK HERE for FULL TEST REPORT on RifleShooter.com »

6mm 6.5 Creedmoor rifleshooter.com Bill Barr barrel length cut-down velocity test chronograph Magnetospeed chrono

6mm 6.5 Creedmoor rifleshooter.com Bill Barr barrel length cut-down velocity test chronograph Magnetospeed chronoFor this latest test, Rifleshooter cut the barrel in one-inch increments from 24″ to 16.1″ (just over legal minimum). Velocities were measured with a MagnetoSpeed V3 chronograph mounted on arm attached to the stock. This allowed the chrono to be adjusted inwards as the barrel was cut shorter, inch by inch.

For the 6mm Creedmoor cartridge, Bill loaded Hornady 108gr ELD Match bullets over 41.5 grains of Hodgdon H4350 with CCI 200 primers in new Starline brass.

The results were interesting to say the least. Bill reports: “Muzzle velocities ranged from 2,893 ft/sec at 24″ to 2,598 ft/sec at 16″ for a decrease in muzzle velocity of 295 ft/sec. Muzzle velocity changes per inch of barrel length ranged from 6 ft/sec per inch between 20 and 19 inches to 63 ft/sec per inch between 19 and 18 inches. Average velocity change per inch of barrel length was 37.9 ft/sec.”

Bill concludes: “An average drop of 37.9 ft/sec/inch of barrel is fairly significant and is what would be expected with a fast moving 6mm cartridge like the 6mm Creedmoor. While I’m used to seeing 6mm Creedmoors with slightly longer barrel lengths than 24″, when coupled with a sound suppressor the additional length can make moving the rifle quickly more difficult.

I’d suggest staying with longer barrel lengths wherever possible with this cartridge. At shorter lengths, it does give up more performance than its big brother the 6.5 Creedmoor.”

More 6mm Creedmoor Velocity Data from 2017 Cut-Down Test

If you’re curious about 6mm Creedmoor velocities at longer barrel lengths, back in 2017 Rifleshooter completed a 6mm Creedmoor barrel cut-down test from 31 inches all the way down to 17 inches. The test included four bullet types from 95 grains to 110 grains. With the 110gr Sierra MK, velocity at 31″ was an impressive 3110 fps. Surprisingly the velocity didn’t decrease that much for the first few inches. Even at 26″ (a five-inch reduction), measured velocity with the 110s was 3073 fps, a loss of 7.4 fps per inch on average. With a barrel shortened all the way to 20″ however, velocity had dropped down to 2949 fps, a significant (161 fps) loss. CLICK HERE for complete results from that 31″-17″ Barrel Cut-Down Test.

6mm 6.5 Creedmoor rifleshooter.com Bill Barr barrel length cut-down velocity test chronograph Magnetospeed chrono

CLICK HERE for 31″ to 17″ 6mm Creedmoor Barrel Test Report »

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