Barrel break in.

[Pathfinder76]

Originally Posted by Salavee

How would the chamber reamer affect the barrel? Probably not a good thing to lap a chamber.

I’ve had barrels lapped post chambering with stellar results.

[260 Rem]

Originally Posted by Salavee

How would the chamber reamer affect the barrel? Probably not a good thing to lap a chamber.

My understanding of Kreiger is that the reamer “marks” that pick up copper would be in the leade.
For those unfamiliar with some of the terms: The “throat” is the area directly in front of the case neck. It is the same diameter as the outside of the case neck and provides some space if brass gets too long, and determines the length of “freebore” which is the space in which the bullet sits (unsupported) until it engages the lands. At the front of the throat is the “leade” which transitions from the throat diameter to that of the bore and is typically cut at a 1 to 1.5 degree angle. Think of a forcing cone. Hope I got that right?
Barrel “blanks” are supplied “lapped” or “unlapped” from the manufacturer and then chambered. Many aftermarket barrels lave been lapped (some twice - after the bore is drilled and again “finish lapped” after the rifling is “cut”. Of course hammer forged barrels go through a different process.
As referenced by Chuck, sometimes an unlapped bore will get lapped on request after clambering.
Salavee - I think that Kreiger is referring to the bullet “ironing out” the tiny “burrs” on the edges of the reamer marks ... nothing related to lapping which in their case would have occurred pre chamber.

[Salavee]

Originally Posted by chuck

I’ve had barrels lapped post chambering with stellar results.

This is the latest method of producing high quality barrels. Savage appear to be the first to use this method for mass produced barrels, maybe five or six years ago... or longer. It, no doubt, has a bearing on the phenomenal accuracy achieved by their product since that time. Now, Bartlein, Pac-Nor and a few others have adopted the boring method as well.

http://bulletin.accurateshooter.com/...l-bore-honing/

http://www.toolingandproduction.com/...lk=1&sr=R&tp=Y

[tchardy1972]

Originally Posted by 260 Rem

My understanding of Kreiger is that the reamer “marks” that pick up copper would be in the leade.
For those unfamiliar with some of the terms: The “throat” is the area directly in front of the case neck. It is the same diameter as the outside of the case neck and provides some space if brass gets too long, and determines the length of “freebore” which is the space in which the bullet sits (unsupported) until it engages the lands. At the front of the throat is the “leade” which transitions from the throat diameter to that of the bore and is typically cut at a 1 to 1.5 degree angle. Think of a forcing cone. Hope I got that right?
Barrel “blanks” are supplied “lapped” or “unlapped” from the manufacturer and then chambered. Many aftermarket barrels lave been lapped (some twice - after the bore is drilled and again “finish lapped” after the rifling is “cut”. Of course hammer forged barrels go through a different process.
As referenced by Chuck, sometimes an unlapped bore will get lapped on request after clambering.
Salavee - I think that Kreiger is referring to the bullet “ironing out” the tiny “burrs” on the edges of the reamer marks ... nothing related to lapping which in their case would have occurred pre chamber.

How many gun smiths don't polish the chamber when the reaming is done? The ones I've seen done all polish the chambe to some degree.

[Salavee]

Originally Posted by tchardy1972

How many gun smiths don't polish the chamber when the reaming is done? The ones I've seen done all polish the chambe to some degree.

Could be. I thought they just used a finishing reamer. A polished chamber wouldn't provide much of a surface for the case to grip during firing would it ?

[Nyksta]

Originally Posted by Salavee

Could be. I thought they just used a finishing reamer. A polished chamber wouldn't provide much of a surface for the case to grip during firing would it ?

The chamber supports the casing during the pressure. Gripping the casing is not necessary, its fully enclosed and headspacing is what is creating the non-movement, not rough gripping chamber walls.

[Salavee]

Originally Posted by Nyksta

The chamber supports the casing during the pressure. Gripping the casing is not necessary, its fully enclosed and headspacing is what is creating the non-movement, not rough gripping chamber walls.

Do you suggest polishing a chamber ? What effect would that have if headspacing was at maximum SAAMI specs, or greater ?

[1Heavyhitr]

Here's a video of man's opinion where he lays out why the barrel break-in process is not necessary. Coming from a guy that's been around the block.. its little long-winded but good. It's a credible one IMO anyway..

https://www.youtube.com/watch?v=jCIi-SklcP8

[West O'5]

Originally Posted by HuntinGuy

560 rounds through my tikka ctr still going strong with no cleaning and no real break in, I cleaned when it was new, then after 20 rounds I did another clean and then stopped. The less you touch your barrel the more consistent and predictable your zero and cold bore shots are. I did see a slight loss in precision (maybe .4” to .6”) after about 300 rounds, but now never shoots over 2/3” (ten shot groups). But my goal is more for consistency than total precision. I think lots of shooters do load development with a freshly “broken in” clean barrel, then see accuracy drop off when the barrel starts to “foul”. I believe this is when you should start load development.


Sent from my iPhone using Tapatalk

Im with this guy in the "copper equilibrium" camp.
"Some" copper fouling is a good thing and promotes better cold bore/first round accuracy and consistency in groups vs. starting each hunting day or range session with a squeaky clean scrubbed bore.

[260 Rem]

Perhaps one of the forums SBR shooters involved with top tier competition will share their opinion ... regarding initial BI and subsequent cleaning?
Perhaps there are also regimes other than the shoot-clean cycle that are favored?

[elkhunter11]

Originally Posted by West O'5

Im with this guy in the "copper equilibrium" camp.
"Some" copper fouling is a good thing and promotes better cold bore/first round accuracy and consistency in groups vs. starting each hunting day or range session with a squeaky clean scrubbed bore.

I find that it varies with the individual barrel, and with the load. I check every one of my hunting rifles with a clean bore, and a fouled bore, and in many cases, I don't notice any difference.

[Nyksta]

Originally Posted by elkhunter11

I find that it varies with the individual barrel, and with the load. I check every one of my hunting rifles with a clean bore, and a fouled bore, and in many cases, I don't notice any difference.

Bingo. All my time shooting, the clean shots are all still inside the group area of the fouled bore group area. Every rifle i have gets cleaned after every use. I used to believe in the copper equilibrium idea and one rifle i had shot about 700 rounds without cleaning, another rifle 1500 rounds. I got the same groupings then as i do now that i clean every time.

Do whatever works for your satisfaction that you are taking care of your guns in your style of use.

[Pathfinder76]

Originally Posted by Nyksta

Bingo. All my time shooting, the clean shots are all still inside the group area of the fouled bore group area. Every rifle i have gets cleaned after every use. I used to believe in the copper equilibrium idea and one rifle i had shot about 700 rounds without cleaning, another rifle 1500 rounds. I got the same groupings then as i do now that i clean every time.

Do whatever works for your satisfaction that you are taking care of your guns in your style of use.

So why are you cleaning all the time?

[260 Rem]

Originally Posted by West O'5

Im with this guy in the "copper equilibrium" camp.
"Some" copper fouling is a good thing and promotes better cold bore/first round accuracy and consistency in groups vs. starting each hunting day or range session with a squeaky clean scrubbed bore.

The idea that having a bit of copper at various places inside the bore ... which will result in “tearing” a bit off of every bullet/jacket as it passes through doesn’t seem like it would enhance consistency? I have always been under the impression that because copper has an affinity to copper, a little “bump” of it sticking inside a groove would grow progressively as each bullet passes over ... and at some point, the “bump” will deform jackets enough for accuracy to fall off. For that reason, I can not rationalize the “equilibrium” theory.
And, when I think of typical groups increasing from 0.4 to 0.6 my reaction would be “holy crap, my agg just jumped by 50% ...what’s wrong.” But, one could also look at it from another perspective and think “wow, more groups under 3/4”, what a great shooter”.

[Nyksta]

Originally Posted by chuck

So why are you cleaning all the time?

Do whatever works for your satisfaction that you are taking care of your guns in your style of use.

Personally I'd rather clean everything out and have a light coating of oil protecting the metal instead of fouling and wind dirt and humidity coating my bore. Others can do as they wish.

[lclund1946]

Originally Posted by 260 Rem

My understanding of Kreiger is that the reamer “marks” that pick up copper would be in the leade.
For those unfamiliar with some of the terms: The “throat” is the area directly in front of the case neck. It is the same diameter as the outside of the case neck and provides some space if brass gets too long, and determines the length of “freebore” which is the space in which the bullet sits (unsupported) until it engages the lands. At the front of the throat is the “leade” which transitions from the throat diameter to that of the bore and is typically cut at a 1 to 1.5 degree angle. Think of a forcing cone. Hope I got that right?
Barrel “blanks” are supplied “lapped” or “unlapped” from the manufacturer and then chambered. Many aftermarket barrels lave been lapped (some twice - after the bore is drilled and again “finish lapped” after the rifling is “cut”. Of course hammer forged barrels go through a different process.
As referenced by Chuck, sometimes an unlapped bore will get lapped on request after clambering.
Salavee - I think that Kreiger is referring to the bullet “ironing out” the tiny “burrs” on the edges of the reamer marks ... nothing related to lapping which in their case would have occurred pre chamber.

There is much confusion about the terms Leade, freebore and throat. Your description of throat is actually describing the neck area of the chamber which is typically 0.010" longer than Maximum case trim length. If you look at a Pacific Tool & Guage reamer print you will see that this then transitions at a 45 degree angle down to the Lead which is the area that the lands are cut out typically 0.0005", or a bit more, over the caliber diameter. PT&G drawings show Freebore as the length of the Lead or area where there is no lands (rifling). Ahead of the Leade is the throat which is cut at an angle to the diameter of the Freebore area, which can range form less than 1 degree to over 3 degrees, cutting out the lands and forming the cone that you describe. Bullet Jump to the Lands is often called freebore but is actually a combination of seating depth, freebore and throat angle. The bullet does not contact the Lead so no copper is transferred until it reaches the throat which is where Kreiger talks about cooper transferring to reamer marks. These usually disappear after about 3 shoot and cleans on a good hand lapped barrel after which copper transfer becomes very minimal and the barrel would be classed as broke in.

[Cappy]

I run a couple patches through the barrel just in case any cutting agents and or material is left in there after cutting/chambering and then just shoot.

I clean only when accuracy falls off or if the barrel is exposed to bad weather. I deliberately told a student not to clean his rifle on a course and he put 1200 rounds through the gun and it was running just fine. In fact I think he put several hundred more through it after that and cleaned it when he was out in the rain.

[260 Rem]

Originally Posted by Cappy

I run a couple patches through the barrel just in case any cutting agents and or material is left in there after cutting/chambering and then just shoot.

I clean only when accuracy falls off or if the barrel is exposed to bad weather. I deliberately told a student not to clean his rifle on a course and he put 1200 rounds through the gun and it was running just fine. In fact I think he put several hundred more through it after that and cleaned it when he was out in the rain.

What is your “tolerance” for “running just fine”?

Iclund - thanks for the more detailed descriptor...and I would agree with your assessment of the “three shot effect”. I used to do a 10 shot BI, but in the past several years have reduced that to 5 shoot-clean cycles. On the Kreigers I run, the 5 cycle seems sufficient.

[Pathfinder76]

Originally Posted by 260 Rem

What is your “tolerance” for “running just fine”?

Iclund - thanks for the more detailed descriptor...and I would agree with your assessment of the “three shot effect”. I used to do a 10 shot BI, but in the past several years have reduced that to 5 shoot-clean cycles. On the Kreigers I run, the 5 cycle seems sufficient.

Shooting MOA at 1000 yds.

[Dick284]

Originally Posted by lclund1946

There is much confusion about the terms Leade, freebore and throat. Your description of throat is actually describing the neck area of the chamber which is typically 0.010" longer than Maximum case trim length. If you look at a Pacific Tool & Guage reamer print you will see that this then transitions at a 45 degree angle down to the Lead which is the area that the lands are cut out typically 0.0005", or a bit more, over the caliber diameter. PT&G drawings show Freebore as the length of the Lead or area where there is no lands (rifling). Ahead of the Leade is the throat which is cut at an angle to the diameter of the Freebore area, which can range form less than 1 degree to over 3 degrees, cutting out the lands and forming the cone that you describe. Bullet Jump to the Lands is often called freebore but is actually a combination of seating depth, freebore and throat angle. The bullet does not contact the Lead so no copper is transferred until it reaches the throat which is where Kreiger talks about cooper transferring to reamer marks. These usually disappear after about 3 shoot and cleans on a good hand lapped barrel after which copper transfer becomes very minimal and the barrel would be classed as broke in.

I think you’ve found the source of info I found a long time ago(and forgot from where)

Hence my shoot and clean for the first 3 shots routine.

Guys will believe what they wanna believe, but for me it’s 3 shots and a few groups, it’s a pittance of my time, considering a barrel starts in the $400 plus tax range, and there’s the gun smiths charges on top of that. That’s a lot of my time!

I wonder out loud how many of the break in minimalists still follow a 5000km oil change regiment with their vehicles?

It still boils down to what are your expectations with said rifle, and is any process that much superior to another that it warrants so much band width and time beating a equine skeleton.

[Pathfinder76]

Originally Posted by Dick284

I wonder out loud how many of the break in minimalists still follow a 5000km oil change regiment with their vehicles?.

Dick, they are nowhere near the same thing. And why would one correlate to the other? Please.

[260 Rem]

Reamer print...what Iclund said
NOTE: This is not a SAAMI spec reamer so 308 guys should not think their factory chambers have similar NK diameter / freebore dimensions.

[Dick284]

Originally Posted by chuck

Dick, they are nowhere near the same thing. And why would one correlate to the other? Please.

I feel there’s a correlation, Chuck.

Why would someone go so far as to neglect the simpilest of regimes?

Would you drive 10000 km on a brand new motor, without changing the oil or at least pulling the filter and having an analysis done on an oil sample?

The same could be said about $800 or more in a new tube and smithing, what’s a shoot and clean for three shots gonna do for harm(bore guides etc used)?

If it does nothing then it was only three cleaning routines, but what if it does some sort of good, like reduced fouling? Your rifle is a small sample, and frankly it exhibits only one thing. No two rifles are the same.

So you don’t believe, that’s cool, run whatcha brung.

I’m on the fence, but not willing to toss the baby out with the bath water, so I do as I do. All I know is that ever since Dan OO showed my Speedy Gonzales’ routine for break in on a SBR rifle he had Speedy build way back when, I’ve done some sort of break in, and I’ve had less fouling issues, and seem to go longer before fouling becomes problematic. So I dunno if the SBR guys get their jollies off on it, I’m willing to at least listen, and see if it can be worked into my little piece of the shooting world.

Again the whole break in thing isn’t quantifiable, since no two barrels and or chamber jobs are identical.

The debate ensues.......

[catnthehat]

I asked two barrel makers a couple of very good gunsmiths this same question many years agin and was told basically this
clean the barrel out completly with Kroil and shoot a few shots then check the patch . There should be no cooper fouling evident .
Factory barrels may need a bit of lapping with kroil and JB's to get them to stop fouling but custom built barrels are normally good to go .

Cat

[260 Rem]

As always there is a broad range of opinions regarding BI and given the fact that results can not be objectively measured ... to a large extent, what each believes boils down to who you trust to be the most credible. To answer that question for myself, I tried to be as objective as possible. To that end, I first looked at the equipment lists for barrels used by the top ten International Benchrest Shooters (Nationals) finishers (both short and long range) to find that the “winningest” brand mentioned...that being both Kreiger and Bartlein. I then checked Bartlein and Kreigers recommendation for their barrels to find out they said similar things regarding breaking-in the “throat”. Both recommend a “shoot-clean” cycles with the number of times being determined by “the patch color” after each cycle. Bartlein recommends a minimum of two, and if my recall is correct, Kreiger does not specify a minimum. Both refer to the “reamer marks” and Kreiger gives a short “what’s happening” explanation. Given the assumption that each of these barrel makers know their product best and have some investment in research and development...I chose to go with their recommendation while using their barrels.

[Pathfinder76]

Looking at patch colour? What a novel idea. Who’d a thunk.

[AltaBorn]

Originally Posted by 1Heavyhitr

Here's a video of man's opinion where he lays out why the barrel break-in process is not necessary. Coming from a guy that's been around the block.. its little long-winded but good. It's a credible one IMO anyway..

https://www.youtube.com/watch?v=jCIi-SklcP8

Good video. He has a pretty good channel too. I've never gone through a lengthly break in process with my rifles and they all have thankfully shot great. Whatever blows your hair back I guess lol

[Salavee]

Originally Posted by lclund1946

There is much confusion about the terms Leade, freebore and throat. Your description of throat is actually describing the neck area of the chamber which is typically 0.010" longer than Maximum case trim length. If you look at a Pacific Tool & Guage reamer print you will see that this then transitions at a 45 degree angle down to the Lead which is the area that the lands are cut out typically 0.0005", or a bit more, over the caliber diameter. PT&G drawings show Freebore as the length of the Lead or area where there is no lands (rifling). Ahead of the Leade is the throat which is cut at an angle to the diameter of the Freebore area, which can range form less than 1 degree to over 3 degrees, cutting out the lands and forming the cone that you describe. Bullet Jump to the Lands is often called freebore but is actually a combination of seating depth, freebore and throat angle. The bullet does not contact the Lead so no copper is transferred until it reaches the throat which is where Kreiger talks about cooper transferring to reamer marks. These usually disappear after about 3 shoot and cleans on a good hand lapped barrel after which copper transfer becomes very minimal and the barrel would be classed as broke in.

All good , but my question was referring to polishing a chamber, not lengthening a throat or cleaning up the leade . AFIK , a chamber is a chamber and ends pretty much at the case mouth. It has specific SAAMI or custom specs peculiar to each different cartridge. The throat and leade are actually different operations that can have arbitrary dimensions or angles and are actually part of the bore. Apart from that, I believe the bullet does contact the leade as it enters the bore (thus the angle) and after it crosses the threshold of the freebore dimension ( throat.) If I'm wrong about all this, I'm sure I will be corrected in short order.
What do you suggest regarding chamber polishing .. good idea, or not so good ?

[HW223]

Originally Posted by 260 Rem

Perhaps one of the forums SBR shooters involved with top tier competition will share their opinion ... regarding initial BI and subsequent cleaning?
Perhaps there are also regimes other than the shoot-clean cycle that are favored?

Not sure what we do in sbr is relevant , we are looking for the accuracy available before the bore fouls with any copper , some barrels will go more than others before copper and other types of fouling show up and degrade accuaracy, this is the difference between a teen agging barrel and a .250 , so if your looking for .5 - 1 moa groups your already outside what is required for sbr, unless you have a bore scope there is no way to know you have the barrel clean , break in is important to the life of the sbr barrel, and not all barrels break in the same depends on the base steel and the finished condition of the bore after lapping .

[260 Rem]

HW223 - IMO SBR practices are very relevant because they involve squeezing every bit of consistency out of a barrel that is possible... by keeping the barrel free of copper and carbon fouling.