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November 14th, 2025

Jim Borden, the very knowledgeable owner of Borden Accuracy, provided an interesting historical insight about barrel fitting and the term “blueprinting”. Jim has posted on his Borden Accuracy Facebook page an explanation of the term “blueprinting” as it originally was used with respect to barrel/shoulder/lug fitting.
Barrel/Shoulder Fit and Blue-Printing
Jim told us: “Something often overlooked on barrel installation is the shoulder fit. Many are so overly obsessed with doing a crank-on fit of threads that the shoulder contact is overlooked. Full, solid barrel shoulder to recoil lug or action face is critical to optimum accuracy and precision.
Many years ago part of the ‘blueprinting’ of an action was the use of Prussian blue to ‘blueprint’ lug fit, thread fit, and barrel shoulder fit. It was a colloquial expression that had nothing to do referring to a blueprint or drawing of the action.” Bet you didn’t know that!
About the photo below, Jim noted: “the fuzzy look on the threads is a liberal coating of Never-Seez thread lubricant.”

Look carefully to see the Prussian Blue applied to the barrel shoulder, plus Never Seez on threads.

January 16th, 2025

This barrel’s shoulder was 0.025″ off the action because Red Locktite had been used on the threads.
Gunsmith Thomas ‘Speedy’ Gonzales offered this interesting report about how NOT to headspace a barrel. Hopefully you never discover something like this…
“A good friend and customer sent this rig in for repair after FedEx damaged the rifle during inbound transport from another smith. After repairing the stock and rebedding it, I decided to re-polish the barrel to make the repair perfect. Well this just added insult to injury as the barrel did not want to come off. After a few choice words, the barrel finally broke free only to reveal something very disturbing. It seems the barrel had been ‘headspaced’ by using RED Loctite to hold it in place.” [Editor: That’s definitely NOT how barrels should be fitted.]
Speedy was not happy: “I hope the smith that did this sees the photos and realized what jeopardy he put my customer in or anyone who shot the rifle for that matter. When cleaned up, the shoulder on the barrel was over 0.0250″ (25 thousandths) away from the face of the receiver.” [Editor: That’s a lot in this business]. Check out the images below to see how much the barrel rotated further inward when cleaned up. The barrel spun in nearly another eighth-turn or more. Not good.

December 15th, 2024

Jim Borden, the very knowledgeable owner of Borden Accuracy, provided an interesting historical insight about barrel fitting and the term “blueprinting”. Jim has posted on his Borden Accuracy Facebook page an explanation of the term “blueprinting” as it originally was used with respect to barrel/shoulder/lug fitting.
Barrel/Shoulder Fit and Blue-Printing
Jim told us: “Something often overlooked on barrel installation is the shoulder fit. Many are so overly obsessed with doing a crank-on fit of threads that the shoulder contact is overlooked. Full, solid barrel shoulder to recoil lug or action face is critical to optimum accuracy and precision.
Many years ago part of the ‘blueprinting’ of an action was the use of Prussian blue to ‘blueprint’ lug fit, thread fit, and barrel shoulder fit. It was a colloquial expression that had nothing to do referring to a blueprint or drawing of the action.” Bet you didn’t know that!
About the photo below, Jim noted: “the fuzzy look on the threads is a liberal coating of Never-Seez thread lubricant.”

Look carefully to see the Prussian Blue applied to the barrel shoulder, plus Never Seez on threads.

January 19th, 2024

Are you seeing unpredictable changes in Point of Impact on your target? Think you may have a scope issue? Well maybe not — when was the last time you checked your BARREL?
Yes scopes do fail, and scope bases/rings do get loose. But sometimes problems with erratic POI shifts are caused by a LOOSE BARREL. This issue came up a while back in our Shooter’s Forum. One member complained that his zero was shifting from day to day — by as much as two inches at 100 yards. He was convinced he had a scope problem, based on erratic POI:
“I think my scope loses 1 to 3 MOA per day. When I shot my rifle Monday it was dead on. On Tuesday it was 1″ low. Then on Wednesday it was 1 or 2″ lower. I don’t get it. — the elevation knob never touched. Scope will track and return to zero that day perfect. Yes EVERYTHING has been checked, nothing loose. What is the chance the erector tube spring has gone south? For the record this is a Vortex GE. Never had a bad scope, but this has me wondering”. — LB
On Forum member told LB to send the scope right back to the manufacturer. Two other members suggested mounting the scope on a different rifle to test. Good advice. That’s generally a smart strategy before you conclude a scope has gone bad…
Could Problem Be the Scope Base?
Two Forum members, ExPiper and Dickn52, suggested checking the scope base, recounting their past experiences with troublesome bases. This was intelligent — anyone with a POI problem should check all the optics attachments:
“Went crazy one day chasing my impacts on a 100-yard target. Shots would group fine for three then go nuts for 4-5. I cranked and un-cranked for about an hour. Then I reached up and the base wobbled on the rifle. Removed scope, tightened base screws and back in business.” — Dickn52
“Years ago I had a problem [where] shots were climbing with almost every shot. I was blaming the scope. However, when removing the scope I noticed that the 20 MOA base was cracked and getting wider with every shot. Needless to say I replaced the base and the problem was solved. — ExPiper
Eureka Moment — The problem was the BARREL, not the Scope
There were many helpful suggestions, but member PirateAmmo steered LB to the real problem — a loose BARREL: “We had a problem on a home-built AR-platform rifle once, barrel was loose a tad…”
Member Snert chimed in: “Yep — I had a PPC that suddenly went 19″ low. Picked up gun off bench by barrel and felt a wiggle. I tightened the barrel and the POI went 19 inches up”.
Problem Solved — Barrel Tightened up and POI Back to Normal
The gentleman with the POI problem took the advice of PirateAmmo and checked his barrel. BINGO! Low and behold, the barrel WAS loose.
LB posted: “Barrel loose by about 2%, checked it twice before and didn’t find it the first two times”.
After LB re-tightened his barrel, his rifle started shooting normally again. No more shooting low by 1-2 inches. Problem solved. The fix didn’t cost a penny and now LB doesn’t have to send a perfectly good optic back to the manufacturer.
Lesson learned? Check ALL the variables before you assume a scope has gone bad. Along with the barrel, also check your action screw tension, and of course the scope base and rings.
March 2nd, 2022

Are you seeing unpredictable changes in Point of Impact on your target? Think you may have a scope issue? Well maybe not — when was the last time you checked your BARREL?
Yes scopes do fail, and scope bases/rings do get loose. But sometimes problems with erratic POI shifts are caused by a LOOSE BARREL. This issue came up recently in our Shooter’s Forum. One member complained that his zero was shifting from day to day — by as much as two inches at 100 yards. He was convinced he had a scope problem, based on erratic POI:
“I think my scope loses 1 to 3 MOA per day. When I shot my rifle Monday it was dead on. On Tuesday it was 1″ low. Then on Wednesday it was 1 or 2″ lower. I don’t get it. — the elevation knob never touched. Scope will track and return to zero that day perfect. Yes EVERYTHING has been checked, nothing loose. What is the chance the erector tube spring has gone south? For the record this is a Vortex GE. Never had a bad scope, but this has me wondering”. — LB
On Forum member told LB to send the scope right back to the manufacturer. Two other members suggested mounting the scope on a different rifle to test. Good advice. That’s generally a smart strategy before you conclude a scope has gone bad…
Could Problem Be the Scope Base?
Two Forum members, ExPiper and Dickn52, suggested checking the scope base, recounting their past experiences with troublesome bases. This was intelligent — anyone with a POI problem should check all the optics attachments:
“Went crazy one day chasing my impacts on a 100-yard target. Shots would group fine for three then go nuts for 4-5. I cranked and un-cranked for about an hour. Then I reached up and the base wobbled on the rifle. Removed scope, tightened base screws and back in business.” — Dickn52
“Years ago I had a problem [where] shots were climbing with almost every shot. I was blaming the scope. However, when removing the scope I noticed that the 20 MOA base was cracked and getting wider with every shot. Needless to say I replaced the base and the problem was solved. — ExPiper
Eureka Moment — The problem was the BARREL, not the Scope
There were many helpful suggestions, but member PirateAmmo steered LB to the real problem — a loose BARREL: “We had a problem on a home-built AR-platform rifle once, barrel was loose a tad…”
Member Snert chimed in: “Yep — I had a PPC that suddenly went 19″ low. Picked up gun off bench by barrel and felt a wiggle. I tightened the barrel and the POI went 19 inches up”.
Problem Solved — Barrel Tightened up and POI Back to Normal
The gentleman with the POI problem took the advice of PirateAmmo and checked his barrel. BINGO! Low and behold, the barrel WAS loose.
LB posted: “Barrel loose by about 2%, checked it twice before and didn’t find it the first two times”.
After LB re-tightened his barrel, his rifle started shooting normally again. No more shooting low by 1-2 inches. Problem solved. The fix didn’t cost a penny and now LB doesn’t have to send a perfectly good optic back to the manufacturer.
Lesson learned? Check ALL the variables before you assume a scope has gone bad. Along with the barrel, also check your action screw tension, and of course the scope base and rings.
January 16th, 2021

Jim Borden, the very knowledgeable owner of Borden Accuracy, provided an interesting historical insight about barrel fitting and the term “blueprinting”. Jim recently posted on the Borden Accuracy Facebook page an explanation of the term “blueprinting” as it originally was used with respect to barrel/shoulder/lug fitting.
Barrel/Shoulder Fit and Blue-Printing
Jim told us: “Something often overlooked on barrel installation is the shoulder fit. Many are so overly obsessed with doing a crank-on fit of threads that the shoulder contact is overlooked. Full, solid barrel shoulder to recoil lug or action face is critical to optimum accuracy and precision.
Many years ago part of the ‘blueprinting’ of an action was the use of Prussian blue to ‘blueprint’ lug fit, thread fit, and barrel shoulder fit. It was a colloquial expression that had nothing to do referring to a blueprint or drawing of the action.” Bet you didn’t know that!
About the photo below, Jim noted: “the fuzzy look on the threads is a liberal coating of Never-Seez thread lubricant.”

Look carefully to see the Prussian Blue applied to the barrel shoulder, plus Never Seez on threads.

February 21st, 2020

This barrel’s shoulder was 0.025″ off the action because Red Locktite had been used on the threads.
Gunsmith Thomas ‘Speedy’ Gonzales offered this interesting report about how NOT to headspace a barrel. Hopefully you never discover something like this…
“A good friend and customer sent this rig in for repair after FedEx damaged the rifle during inbound transport from another smith. After repairing the stock and rebedding it, I decided to re-polish the barrel to make the repair perfect. Well this just added insult to injury as the barrel did not want to come off. After a few choice words, the barrel finally broke free only to reveal something very disturbing. It seems the barrel had been ‘headspaced’ by using RED Loctite to hold it in place.” [Editor: That’s definitely NOT how barrels should be fitted.]
Speedy was not happy: “I hope the smith that did this sees the photos and realized what jeopardy he put my customer in or anyone who shot the rifle for that matter. When cleaned up, the shoulder on the barrel was over 0.0250″ (25 thousandths) away from the face of the receiver.” [Editor: That’s a lot in this business]. Check out the images below to see how much the barrel rotated further inward when cleaned up. The barrel spun in nearly another eighth-turn or more. Not good.

January 22nd, 2020

Are you seeing unpredictable changes in Point of Impact on your target? Think you may have a scope issue? Well maybe not — when was the last time you checked your BARREL?
Yes scopes do fail, and scope bases/rings do get loose. But sometimes problems with erratic POI shifts are caused by a LOOSE BARREL. This issue came up recently in our Shooter’s Forum. One member complained that his zero was shifting from day to day — by as much as two inches at 100 yards. He was convinced he had a scope problem, based on erratic POI:
“I think my scope loses 1 to 3 MOA per day. When I shot my rifle Monday it was dead on. On Tuesday it was 1″ low. Then on Wednesday it was 1 or 2″ lower. I don’t get it. — the elevation knob never touched. Scope will track and return to zero that day perfect. Yes EVERYTHING has been checked, nothing loose. What is the chance the erector tube spring has gone south? For the record this is a Vortex GE. Never had a bad scope, but this has me wondering”. — LB
On Forum member told LB to send the scope right back to the manufacturer. Two other members suggested mounting the scope on a different rifle to test. Good advice. That’s generally a smart strategy before you conclude a scope has gone bad…
Could Problem Be the Scope Base?
Two Forum members, ExPiper and Dickn52, suggested checking the scope base, recounting their past experiences with troublesome bases. This was intelligent — anyone with a POI problem should check all the optics attachments:
“Went crazy one day chasing my impacts on a 100-yard target. Shots would group fine for three then go nuts for 4-5. I cranked and un-cranked for about an hour. Then I reached up and the base wobbled on the rifle. Removed scope, tightened base screws and back in business.” — Dickn52
“Years ago I had a problem [where] shots were climbing with almost every shot. I was blaming the scope. However, when removing the scope I noticed that the 20 MOA base was cracked and getting wider with every shot. Needless to say I replaced the base and the problem was solved. — ExPiper
Eureka Moment — The problem was the BARREL, not the Scope
There were many helpful suggestions, but member PirateAmmo steered LB to the real problem — a loose BARREL: “We had a problem on a home-built AR-platform rifle once, barrel was loose a tad…”
Member Snert chimed in: “Yep — I had a PPC that suddenly went 19″ low. Picked up gun off bench by barrel and felt a wiggle. I tightened the barrel and the POI went 19 inches up”.
Problem Solved — Barrel Tightened up and POI Back to Normal
The gentleman with the POI problem took the advice of PirateAmmo and checked his barrel. BINGO! Low and behold, the barrel WAS loose.
LB posted: “Barrel loose by about 2%, checked it twice before and didn’t find it the first two times”.
After LB re-tightened his barrel, his rifle started shooting normally again. No more shooting low by 1-2 inches. Problem solved. The fix didn’t cost a penny and now LB doesn’t have to send a perfectly good optic back to the manufacturer.
Lesson learned? Check ALL the variables before you assume a scope has gone bad. Along with the barrel, also check your action screw tension, and of course the scope base and rings.
April 7th, 2018

There is a new book, Chambering Rifles for Accuracy, that will benefit folks who want to understand the chambering process, and potentially learn to chamber a barrel on their own. We caution, however — you really need a skilled, hands-on mentor for this this task. For someone without a lot of machining experience, chambering can be tricky, and working with lathes can be dangerous to say the least.*
With those cautions stated, this book will help any gun-owner understand how chambering is done, and what to look for when assessing chambering work by commercial gunsmiths. Chambering Rifles for Accuracy is co-authored by Gordy Gritters and Fred Zeglin. The methods detailed in this book can be used equally well by gunsmiths in a professional shop, and by skilled, well-trained hobbyists working in a home workshop. The book costs $49.95 from Amazon.
Gordy Gritters is a highly-respected gunsmith and gunsmithing instructor. Gordy has built many match-winning competition rifles so he knows his stuff. Fred is a gunsmith, gunsmithing instructor, author, and is the owner of 4-D Reamer Rentals, so he is very knowledgeable on the use and care of reamers. Fred has extensive experience building high-accuracy hunting rifles.
Fred wrote the first half of the book, which covers what is needed to prepare for and chamber high-accuracy hunting barrels. Zeglin lists all the tools needed such as reamers, micrometer reamer stops, headspace gauges, and more.
Gordy wrote the second half of the book, which goes beyond basic chambering. Gordy covers setting up a lathe for chambering barrels through the headstock, various dialing-in methods commonly used, how to deal with curvature in rifle bores, and how to deal with reamer chatter (especially prevalent in 5R-type barrels). Then Gordy covers the entire dialing-in/threading/fitting/chambering/crowning process used to build a benchrest-quality rifle. Gordy also explaines how to ream custom chamber necks, and how to throat the chamber for specific bullets or for a specific purpose.

Gordy Gritters also created an excellent DVD, “Chambering a Championship Match Barrel”. No other chambering video shows the entire chambering process step-by-step with the advanced, precision techniques used by master gunsmiths. Gordy has built several rifles that hold world records and have won National Championships. This is a professional 90-minute production from Grizzly Industrial. You can purchase this $69.95 DVD from Gordy’s website or from Grizzly Industrial.
*This Editor’s own uncle suffered a severe arm injury while working with a lathe. He was not an amateur — he had done lathe and mill work for over 40 years. But a shirt-sleeve caught in the spinning chuck. The results were horrific.
March 8th, 2018

This barrel’s shoulder was 0.025″ off the action because Red Locktite had been used on the threads.
Gunsmith Thomas ‘Speedy’ Gonzales offered this interesting report about how NOT to headspace a barrel. Hopefully you never discover something like this…
“A good friend and customer sent this rig in for repair after FedEx damaged the rifle during inbound transport from another smith. After repairing the stock and rebedding it, I decided to re-polish the barrel to make the repair perfect. Well this just added insult to injury as the barrel did not want to come off. After a few choice words, the barrel finally broke free only to reveal something very disturbing. It seems the barrel had been ‘headspaced’ by using RED Loctite to hold it in place.” [Editor: That’s definitely NOT how barrels should be fitted.]
Speedy was not happy: “I hope the smith that did this sees the photos and realized what jeopardy he put my customer in or anyone who shot the rifle for that matter. When cleaned up, the shoulder on the barrel was over 0.0250″ (25 thousandths) away from the face of the receiver.” [Editor: That’s a lot in this business]. Check out the images below to see how much the barrel rotated further inward when cleaned up. The barrel spun in nearly another eighth-turn or more. Not good.

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