I've not yet shot my new Sako 75 Stailess 7mm08 and need to break-in barrel. Being I don't have reloading equipment and plan on shooting factory ammo for now...I'm wondering if it matters what type of ammo is used for the break in? Would it be OK to use the cheaper line of Remington,Winchester,etc. in the 140 grain bullets or should I use what I hope to be the ammo that is better for deer hunting like Hornady SST or Remington AccuTip which cost more money. I just don't know how reliable the one shot and clean method during the break-in is for testing ammo for accuracy at the same time. When it comes right down to it I've only broke in one other center fire rifle in my life and that was a Browning Boss Rifle so ammo testing wasn't being done since I had planed on adjusting the Boss to the ammo. Thanks to any input on this subject.
Breaking in new barrel question
- Thread starter fourinone
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Fiftydriver
Official LRH Sponsor
Does not really matter. I personally like as heavy a bullet as I can get simply because there is more baring surface working on the bore but I would certainly not spend alot of extra money just for added bullet weight.
Stay away from coated bullets of any kind such as moly, oxidized or dry film coating. These reduce friction, how much is a topic of debate but they will take longer to break in the barrel with these bullets. Use a standard grade bullet, Rem Corlokt, Win Power points, does not really matter.
THe most important thing is that you actually break the barrel in.
Good Shooting!!
Kirby Allen(50)
Stay away from coated bullets of any kind such as moly, oxidized or dry film coating. These reduce friction, how much is a topic of debate but they will take longer to break in the barrel with these bullets. Use a standard grade bullet, Rem Corlokt, Win Power points, does not really matter.
THe most important thing is that you actually break the barrel in.
Good Shooting!!
Kirby Allen(50)
G
Guest
Guest
I agree with fifty driver. Don't spend extra money for ammo to break in. I use the cheapest crap I can get.
I wouldn't advise testing for accuracy while breaking in the barrel. I mean if you shoot at the same spot on the target with the same scope setting and you want to see how accurate it is out the box thats fine. But, your gun will shoot best after its broken in. So that is when you should start testing loads for accuracy. I'm breaking in my 338 Lapua without a scope. I just fire away! I'm only concerned with the break-in.
When it comes to break-in technique i'm in the minority. I do 3 shot & clean 3 times then 5 shot & clean. I shoot for accuracy during the 5 shot & clean. I do this until it shoots. I find no reason for 1 shot clean. I should note that I also have a custom barrel. I've never broken in a factory barrel so maybe there is a difference. But I also think that a barrel will eventually break itself in anyway. The reason for the shoot & clean is to speed up the process.
Guys, I know most of you do not agree with me so don't flame me for having a different opinion.
I wouldn't advise testing for accuracy while breaking in the barrel. I mean if you shoot at the same spot on the target with the same scope setting and you want to see how accurate it is out the box thats fine. But, your gun will shoot best after its broken in. So that is when you should start testing loads for accuracy. I'm breaking in my 338 Lapua without a scope. I just fire away! I'm only concerned with the break-in.
When it comes to break-in technique i'm in the minority. I do 3 shot & clean 3 times then 5 shot & clean. I shoot for accuracy during the 5 shot & clean. I do this until it shoots. I find no reason for 1 shot clean. I should note that I also have a custom barrel. I've never broken in a factory barrel so maybe there is a difference. But I also think that a barrel will eventually break itself in anyway. The reason for the shoot & clean is to speed up the process.
Guys, I know most of you do not agree with me so don't flame me for having a different opinion.
Thanks for the info on this subject. The one and only other center fire I broke in and a new Anschutz 22mag rimfire was done by following some directions in a book I read about 15 years ago and don't now rember what it said to do. What is the main thing to look for to know that the barrel is broke in? Thanks: John
G
Guest
Guest
Two things.
1. A broken in barrel cleans easier & faster.
2. Accuracy is improved.
Thats about it, good luck!
1. A broken in barrel cleans easier & faster.
2. Accuracy is improved.
Thats about it, good luck!
kwanjangnihm
Well-Known Member
I read this article the other day but have not tried this method. Any thoughts??
I've spent the last few months trying to get a better understanding of what a barrel break-in process is and how to properly clean a rifle. What to do and what not to do.
I've spent a lot of time on this board, the BR board and other shooting boards listening to members and what works for them. Conclusion, what works for some, doesn't work for others. Being an engineer in the telecommunications field, when it's broke or you don't understand something you go back to manufactures specs and schematics. So that's kinda what I did on this subject.
I've talked with 4 metallurgist and 3 barrel manufactures (Rock Creek, Hart and Shilen), on the subject. From a scientific point of view, they all said and agreed to pretty much the same thing.
First, barrel break-in processes keep them in business. This shoot and clean, shoot and clean every round or few rounds break-in process only damages your brand new match barrel. Think of a car engine for a moment. Why do we use oil in the engine? To prevent metal-to-metal contact and reduce friction between two metal surfaces. Your barrel is no different from the engine. Mike Rock at Rock Creek barrels gave me the most detailed explanations on barrels and ballistics. Mike has his degree in metallurgy; he was also the chief ballistics engineer for the Army for many years at the Aberdeen Proving grounds. Stan Rivenbark was one of the top ballistic engineers for Raytheon before he retired in the 70's and also has a degree in metallurgy. I also talked with two local metallurgists here in North TX. I confirmed my findings with each person to see if they agreed or disagreed. Conclusion, they all agreed with each other's assessments.
When Mike worked at Aberdeen proving grounds, the Army used high speed bore videos with mirrors, thermal imaging and computers to analyze any and everything that happens when the firing pin hits the primer and the round goes off. When the primer ignites there is enough pressure to move the bullet forward into the lands. The bullet then stops. As the primer ignites the powder, more pressure builds moving the bullet forward where it can stop again. Once there is enough pressure from the round going off, the bullet is moved down out the barrel. All of this happens in nanoseconds (billionths of a second). Your bullet starts and stops at least twice and sometimes three times before it leaves the barrel. This is fact.
If you clean every round or every few rounds during your barrel break-in process or clean your rifle so well after shooting that you take it down to the bare metal, you've created a metal-to-metal contact surface for the next time you shoot the gun. So what's the problem with this you ask? Just like your car engine, metal-to-metal contact will sheer away layers of metal from each surface. So if your bullet is starting and stopping two or three times as it leaves the barrel, that's two or three places for metal-to-metal contact to happen as well as the rest of your bore. The use of JB's and Flitz can and will take you down to metal-to-metal contact. For all intents and purposes, JB's and Flitz are not the most ideal products for cleaning your rifle.
According to Mike Rock, and the other barrel manufactures agreed, all you need to avoid this metal-to-metal contact is a good burnish in the barrel. Shilen, Hart and Rock Creek will all void your barrel warranty if you shoot moly bullets and for good reason. This is not to say that moly is necessarily bad for a barrel, but it is when applied to bullets. There is no way possible to coat a bore with moly bullets. The bullet contact surface in the barrel is only so big. But when your round goes off, moly comes off the contact surface of the bullet in the throat area of the rifle and is bonded to the barrel due to the excessive heat and pressure. We're not talking coated or adhered to, we're talking bonded, d**n near permanent. With this, some of the jacket coating comes off the bullet. Follow this up with another round and you've now embedded the copper jacket between layers of bonded moly. This is the beginning of the black moly ring, which ruins countless barrels and is so hard; it can hardly be scraped off with a screwdriver's corner edge. This is what happened to a new Shilen SS select match barrel I had to have replaced with less than 400 rounds through it. I can't talk for Fastex as I don't or none of the folks I talked to knew enough about the product to comment on it. When I talked to Mike about my new barrel and the barrel break-in process, this is what he had to say. He first hand laps each barrel with a lead lap. He then uses two products from Sentry Solutions, a product called Smooth Coat, which is an alcohol and moly based product. He applies wet patches of Smooth Coats until the bore is good and saturated and lets it sit until the alcohol evaporates. The barrel now has loose moly in it. Next he uses a product called BP-2000, which is a very fine moly powder. Applied to a patch wrapped around a bore brush, he makes a hundred passes or so through the barrel very rapidly before having to rest. He repeats this process with fresh patches containing the moly powder a few more times. What he is doing is burnishing the barrel surface with moly and filling in any fine micro lines left by the hand lapping. He then uses a couple of clean patches to knock out any remaining moly left in the bore.
With the barrel burnished with moly, this will prevent any metal-to-metal contact during the barrel break-in process. My instructions for barrel break-in were quite simple. Shoot 20 rounds (non-moly bullets) with no cleaning, as this will further burnish the barrel. Done! Now shoot and clean using your regular regimen of cleaning and if you have to use JB's or flitz type products, go very easy with them, or better yet avoid them. Never clean down to bare metal. He said most of the cleaning products do a great job, don't be afraid to use a brush and go easy on the ammonia-based products for removing copper fouling. Basically don't let the ammonia-based products remain in the barrel for long lengths of time.
Well that's the long and skinny from the scientific point of view on the subject. If you're ever in doubt about the real condition of your barrel, take it to someone who has a bore scope and even better if someone has a bore scope that can magnify the view. You may be surprised at what is really going on in your barrel. /ubbthreads/images/graemlins/laugh.gif
Jeff in Florida
I've spent the last few months trying to get a better understanding of what a barrel break-in process is and how to properly clean a rifle. What to do and what not to do.
I've spent a lot of time on this board, the BR board and other shooting boards listening to members and what works for them. Conclusion, what works for some, doesn't work for others. Being an engineer in the telecommunications field, when it's broke or you don't understand something you go back to manufactures specs and schematics. So that's kinda what I did on this subject.
I've talked with 4 metallurgist and 3 barrel manufactures (Rock Creek, Hart and Shilen), on the subject. From a scientific point of view, they all said and agreed to pretty much the same thing.
First, barrel break-in processes keep them in business. This shoot and clean, shoot and clean every round or few rounds break-in process only damages your brand new match barrel. Think of a car engine for a moment. Why do we use oil in the engine? To prevent metal-to-metal contact and reduce friction between two metal surfaces. Your barrel is no different from the engine. Mike Rock at Rock Creek barrels gave me the most detailed explanations on barrels and ballistics. Mike has his degree in metallurgy; he was also the chief ballistics engineer for the Army for many years at the Aberdeen Proving grounds. Stan Rivenbark was one of the top ballistic engineers for Raytheon before he retired in the 70's and also has a degree in metallurgy. I also talked with two local metallurgists here in North TX. I confirmed my findings with each person to see if they agreed or disagreed. Conclusion, they all agreed with each other's assessments.
When Mike worked at Aberdeen proving grounds, the Army used high speed bore videos with mirrors, thermal imaging and computers to analyze any and everything that happens when the firing pin hits the primer and the round goes off. When the primer ignites there is enough pressure to move the bullet forward into the lands. The bullet then stops. As the primer ignites the powder, more pressure builds moving the bullet forward where it can stop again. Once there is enough pressure from the round going off, the bullet is moved down out the barrel. All of this happens in nanoseconds (billionths of a second). Your bullet starts and stops at least twice and sometimes three times before it leaves the barrel. This is fact.
If you clean every round or every few rounds during your barrel break-in process or clean your rifle so well after shooting that you take it down to the bare metal, you've created a metal-to-metal contact surface for the next time you shoot the gun. So what's the problem with this you ask? Just like your car engine, metal-to-metal contact will sheer away layers of metal from each surface. So if your bullet is starting and stopping two or three times as it leaves the barrel, that's two or three places for metal-to-metal contact to happen as well as the rest of your bore. The use of JB's and Flitz can and will take you down to metal-to-metal contact. For all intents and purposes, JB's and Flitz are not the most ideal products for cleaning your rifle.
According to Mike Rock, and the other barrel manufactures agreed, all you need to avoid this metal-to-metal contact is a good burnish in the barrel. Shilen, Hart and Rock Creek will all void your barrel warranty if you shoot moly bullets and for good reason. This is not to say that moly is necessarily bad for a barrel, but it is when applied to bullets. There is no way possible to coat a bore with moly bullets. The bullet contact surface in the barrel is only so big. But when your round goes off, moly comes off the contact surface of the bullet in the throat area of the rifle and is bonded to the barrel due to the excessive heat and pressure. We're not talking coated or adhered to, we're talking bonded, d**n near permanent. With this, some of the jacket coating comes off the bullet. Follow this up with another round and you've now embedded the copper jacket between layers of bonded moly. This is the beginning of the black moly ring, which ruins countless barrels and is so hard; it can hardly be scraped off with a screwdriver's corner edge. This is what happened to a new Shilen SS select match barrel I had to have replaced with less than 400 rounds through it. I can't talk for Fastex as I don't or none of the folks I talked to knew enough about the product to comment on it. When I talked to Mike about my new barrel and the barrel break-in process, this is what he had to say. He first hand laps each barrel with a lead lap. He then uses two products from Sentry Solutions, a product called Smooth Coat, which is an alcohol and moly based product. He applies wet patches of Smooth Coats until the bore is good and saturated and lets it sit until the alcohol evaporates. The barrel now has loose moly in it. Next he uses a product called BP-2000, which is a very fine moly powder. Applied to a patch wrapped around a bore brush, he makes a hundred passes or so through the barrel very rapidly before having to rest. He repeats this process with fresh patches containing the moly powder a few more times. What he is doing is burnishing the barrel surface with moly and filling in any fine micro lines left by the hand lapping. He then uses a couple of clean patches to knock out any remaining moly left in the bore.
With the barrel burnished with moly, this will prevent any metal-to-metal contact during the barrel break-in process. My instructions for barrel break-in were quite simple. Shoot 20 rounds (non-moly bullets) with no cleaning, as this will further burnish the barrel. Done! Now shoot and clean using your regular regimen of cleaning and if you have to use JB's or flitz type products, go very easy with them, or better yet avoid them. Never clean down to bare metal. He said most of the cleaning products do a great job, don't be afraid to use a brush and go easy on the ammonia-based products for removing copper fouling. Basically don't let the ammonia-based products remain in the barrel for long lengths of time.
Well that's the long and skinny from the scientific point of view on the subject. If you're ever in doubt about the real condition of your barrel, take it to someone who has a bore scope and even better if someone has a bore scope that can magnify the view. You may be surprised at what is really going on in your barrel. /ubbthreads/images/graemlins/laugh.gif
Jeff in Florida
Agunner012
Well-Known Member
Interesting comparison to a car engine. I often wondered why you wouldn't want a very light film of oil down a new barrel? Patch some gun oil followed by a dry patch to eliminate the metal to metal. This would allow a longer slower break-in.
An old time gunsmith told me that he would clean a barrel before firing it, then lightly oil the barrel, followed by a dry patch. Fire 3 rounds remove carbon and repeat the process for 1 box of ammo. Then clean throughly and shoot as normal.
Any thoughts on that idea?
Andrew
An old time gunsmith told me that he would clean a barrel before firing it, then lightly oil the barrel, followed by a dry patch. Fire 3 rounds remove carbon and repeat the process for 1 box of ammo. Then clean throughly and shoot as normal.
Any thoughts on that idea?
Andrew
winmagman
Well-Known Member
kwanjangnihm
Mike Rock told me the same thing when I was there working on my .243. He also provided me with a sample kit of the Smooth Coat and BP 2000 that I just finished using to break the gun in. I followed the the instruction that came with the kit and I have to say it was a whole lot easier than the shoot 1 clean method that I used on my previous guns. I don't think the barrel broke in using fewer rounds, I was just able to get those rounds down the tube in much less time with much less work.
Two weeks ago I ran 21 shots through the barrel while doing some pressure testing, then yesterday tried out some loads for groups. Using RE 22 with 105gr Amaxes I managed .495 with 44.2 grs. .399 with 44.4, grs and .514 with 44.6 grs. I shot some other grops at lower charges but they weren't as nice.
Point I'm trying to make is with only 50 rounds down the barrel and groups like those I'd have to say the Sentry solutions products sure didn't hurt anything and definitly made the break in job easier.
Chris
Mike Rock told me the same thing when I was there working on my .243. He also provided me with a sample kit of the Smooth Coat and BP 2000 that I just finished using to break the gun in. I followed the the instruction that came with the kit and I have to say it was a whole lot easier than the shoot 1 clean method that I used on my previous guns. I don't think the barrel broke in using fewer rounds, I was just able to get those rounds down the tube in much less time with much less work.
Two weeks ago I ran 21 shots through the barrel while doing some pressure testing, then yesterday tried out some loads for groups. Using RE 22 with 105gr Amaxes I managed .495 with 44.2 grs. .399 with 44.4, grs and .514 with 44.6 grs. I shot some other grops at lower charges but they weren't as nice.
Point I'm trying to make is with only 50 rounds down the barrel and groups like those I'd have to say the Sentry solutions products sure didn't hurt anything and definitly made the break in job easier.
Chris
Jeff in Florida...Wow!! That is a new one on me for sure! I'm not sure what Sako does to their Stainless Steel barrels as far as lapping or not lapping? I'm going to assume they don't do any barrel lapping on their factory hunting rifles. I wonder if this BP 2000 & Smooth Coat stuff can be bought along with instructions to do-it-yourself people?? Maybe the Tubb Fire Lapping kit would be a starting point?? I've seen somewhere people using a graphite based product to treat their barrels with...will this do the same thing as the Moly? Thanks for that info on the subject..All though, now I don't know what to do as to breaking in the barrel. I guess I'll hope to get enough responce on this sugject to come-up with a process that hopefuly will do more good than harm.
winmagman
Well-Known Member
fourinone and others
Here is the link to the website for Smoothcoat and BP 2000, if nothing else it's interesting reading.Sentry Solutions ltd.
This links to the barrel treatment page barrel treatment
Chris
Here is the link to the website for Smoothcoat and BP 2000, if nothing else it's interesting reading.Sentry Solutions ltd.
This links to the barrel treatment page barrel treatment
Chris
G
Guest
Guest
The guys at Krieger are the ones that told me about the myths of barrel break-in. Their attitude is that eventually it will be broken in. Of course we want that sooner than later.
Thanks Winmagman, for the links for these products mentioned. I think I may give this a try. I'm still thinking about the fire lapping to do first. I don't have reloading equipment and will have to see if a freind will let me reload with his equipment at least long enough to load some of the fire lapping rounds. Does any one know if the bullet depth matters in the Tubb fire lapping kit or is somewhere near factory ammo OAL ok?? And the type of powder to use fire lapping a 7mm08...does it matter?? Thanks: John
Agunner012
Well-Known Member
Here is a thread written by Gale McMillan on barrel break-in. His credentials spoke for themselves.
The break in fad was started by a fellow I helped get started in the barrel business. He started putting a set of break in instructions in ever barrel he shipped. One came into the shop to be installed and I read it and the next time I saw him I asked him What was with this break in crap? His answer was Mac, My share of the market is about 700 barrels a year. I cater to the target crowd and they shoot a barrel about 3000 rounds before they change it. If each one uses up 100 rounds of each barrel breaking it in you can figure out how many more barrels I will get to make each year. If you will stop and think that the barrel doesn't know whether you are cleaning it every shot or every 5 shots and if you are removing all foreign material that has been deposited in it since the last time you cleaned it what more can you do? When I ship a barrel I send a recommendation with it that you clean it ever chance you get with a brass brush pushed through it at least 12 times with a good solvent and followed by two and only 2 soft patches. This means if you are a bench rest shooter you clean every 7 or 8 rounds. If you are a high power shooter you clean it when you come off the line after 20 rounds. If you follow the fad of cleaning every shot for X amount and every 2 shots for X amount and so on the only thing you are accomplishing is shortening the life of the barrel by the amount of rounds you shot during this process. I always say Monkey see Monkey do, now I will wait on the flames but before you write them, please include what you think is happening inside your barrel during break in that is worth the expense and time you are spending during break in.
No flame here Mr. Mac. When my personal history is comparable to yours, I may throw rocks - not until then though.
I have done this on factory barrels and had good results. I usually use JB compound for the first few shots and through cleaning after range sessions. The aggressive use of JB seems to smooth things up pretty quickly. (duh) I do not have a custom barrel on any of my rifles. (yet)
Would you still hold that the procedure is unneeded on factory barrels?
I answered this and lost it on transfer so will shorten this one and try to get my point across in fewer words. When some one uses JB on one of my rifles I void the warrantee! For two reasons. ! It dimensionally alters the barrel dimensions and not evenly and the second reason is the barrel maker laps the barrel with a grit of lapping compound that is most effective in preventing metal fouling. Then a customer polishes that finish away with JB.
I wouldn't be as apposed to it if it were applied on a lead lap and very sparingly. It is very obvious when you look at a barrel with a bore scopes all the sharp edges are worn off the rifling. if it has JB used on it on a regular basis. As you know ,it is an abrasive of about 1000 grit. As for using it on factory barrels I will say that while it is difficult to hurt a production barrel but the thing that hurts a match barrel will do the same to a factory barrel
I understand what you are saying about JB compound, but, for example, I have a rifle in .375x338 Mag that copper fouls so badly that even JB bore paste doesn't do it. Even the stronger solvents don't seem to phase the stuff.
I think I have more of this article somewhere for anyone who's interested. No flame intended I'm just looking to share what I've read.
Andrew
The break in fad was started by a fellow I helped get started in the barrel business. He started putting a set of break in instructions in ever barrel he shipped. One came into the shop to be installed and I read it and the next time I saw him I asked him What was with this break in crap? His answer was Mac, My share of the market is about 700 barrels a year. I cater to the target crowd and they shoot a barrel about 3000 rounds before they change it. If each one uses up 100 rounds of each barrel breaking it in you can figure out how many more barrels I will get to make each year. If you will stop and think that the barrel doesn't know whether you are cleaning it every shot or every 5 shots and if you are removing all foreign material that has been deposited in it since the last time you cleaned it what more can you do? When I ship a barrel I send a recommendation with it that you clean it ever chance you get with a brass brush pushed through it at least 12 times with a good solvent and followed by two and only 2 soft patches. This means if you are a bench rest shooter you clean every 7 or 8 rounds. If you are a high power shooter you clean it when you come off the line after 20 rounds. If you follow the fad of cleaning every shot for X amount and every 2 shots for X amount and so on the only thing you are accomplishing is shortening the life of the barrel by the amount of rounds you shot during this process. I always say Monkey see Monkey do, now I will wait on the flames but before you write them, please include what you think is happening inside your barrel during break in that is worth the expense and time you are spending during break in.
No flame here Mr. Mac. When my personal history is comparable to yours, I may throw rocks - not until then though.
I have done this on factory barrels and had good results. I usually use JB compound for the first few shots and through cleaning after range sessions. The aggressive use of JB seems to smooth things up pretty quickly. (duh) I do not have a custom barrel on any of my rifles. (yet)
Would you still hold that the procedure is unneeded on factory barrels?
I answered this and lost it on transfer so will shorten this one and try to get my point across in fewer words. When some one uses JB on one of my rifles I void the warrantee! For two reasons. ! It dimensionally alters the barrel dimensions and not evenly and the second reason is the barrel maker laps the barrel with a grit of lapping compound that is most effective in preventing metal fouling. Then a customer polishes that finish away with JB.
I wouldn't be as apposed to it if it were applied on a lead lap and very sparingly. It is very obvious when you look at a barrel with a bore scopes all the sharp edges are worn off the rifling. if it has JB used on it on a regular basis. As you know ,it is an abrasive of about 1000 grit. As for using it on factory barrels I will say that while it is difficult to hurt a production barrel but the thing that hurts a match barrel will do the same to a factory barrel
I understand what you are saying about JB compound, but, for example, I have a rifle in .375x338 Mag that copper fouls so badly that even JB bore paste doesn't do it. Even the stronger solvents don't seem to phase the stuff.
I think I have more of this article somewhere for anyone who's interested. No flame intended I'm just looking to share what I've read.
Andrew
Waltech Jim
Well-Known Member
fourinone,
Very little changes with respect to the barrel, it is the throat area that should be the focus of any barrel break in, and hence discussion. This is a copy of my contribution to the last LRH thread on barrel break in. I edited the following for the sake of time.
"It has been well established the chambering of a barrel leaves marks or ridges if you will, that are transverse to the passage of the bullet. These ridges, especially early in the barrels life will scrape a small amount of copper from the bullet as it passes over them. Just after the bullet passes over these grooves, if we were able to take a high speed picture of them, we would see copper in the valleys of these grooves, much like what would happen if you scraped a bullet over a file. But the copper does not stay there long. As the temperature and pressure rise in the throat area (from the burning powder) the copper vaporizes and is carried down the barrel and deposited.
The very tips of the ridges are now subjected to heat that raises the temperature to the point the metal becomes relatively soft. As the burning powder scrapes across these superheated ridges it removes the very top of them. With the next round there is slightly less of a ridge present and hence less copper and steel is removed. Sharp pointed ridges with narrow bases, from a sharp reamer tend to be worn down quickly. Rounded, broad based ridges from a dull reamer wear more slowly and produce more copper fouling.
You can demonstrate this quite well with an old file. Take a torch and play it across the teeth. You can very quickly get the teeth to the melting point while the backbone remains relatively cool.
At least in my mind this explains why chambers made with sharp reamers take few rounds to break in and deposit little copper in the process. Also that (some) factory barrels may require many more rounds to break in."
------------------------------------------------
John M. urged me to talk with Krieger on the phone as they recommend a relatively common break in proceedure (for their barrels) on their web site and he got a somewhat different opinion on the phone. I called Krieger and their answer to my questions were:
1. "...barrel break in is not a fallacy"
2. "...barrels chambered with sharp reamers will take very little break in. Maybe none at all. Chamber (throats) cut with dull reamers can take considerably longer to break in. If the barrel is shooting good and deposits little copper, it is broke in."
I have the highest respect for Mr. Allens' opinions. I believe he said it best. "The most important thing is that you actually break the barrel in"
Jim
Very little changes with respect to the barrel, it is the throat area that should be the focus of any barrel break in, and hence discussion. This is a copy of my contribution to the last LRH thread on barrel break in. I edited the following for the sake of time.
"It has been well established the chambering of a barrel leaves marks or ridges if you will, that are transverse to the passage of the bullet. These ridges, especially early in the barrels life will scrape a small amount of copper from the bullet as it passes over them. Just after the bullet passes over these grooves, if we were able to take a high speed picture of them, we would see copper in the valleys of these grooves, much like what would happen if you scraped a bullet over a file. But the copper does not stay there long. As the temperature and pressure rise in the throat area (from the burning powder) the copper vaporizes and is carried down the barrel and deposited.
The very tips of the ridges are now subjected to heat that raises the temperature to the point the metal becomes relatively soft. As the burning powder scrapes across these superheated ridges it removes the very top of them. With the next round there is slightly less of a ridge present and hence less copper and steel is removed. Sharp pointed ridges with narrow bases, from a sharp reamer tend to be worn down quickly. Rounded, broad based ridges from a dull reamer wear more slowly and produce more copper fouling.
You can demonstrate this quite well with an old file. Take a torch and play it across the teeth. You can very quickly get the teeth to the melting point while the backbone remains relatively cool.
At least in my mind this explains why chambers made with sharp reamers take few rounds to break in and deposit little copper in the process. Also that (some) factory barrels may require many more rounds to break in."
------------------------------------------------
John M. urged me to talk with Krieger on the phone as they recommend a relatively common break in proceedure (for their barrels) on their web site and he got a somewhat different opinion on the phone. I called Krieger and their answer to my questions were:
1. "...barrel break in is not a fallacy"
2. "...barrels chambered with sharp reamers will take very little break in. Maybe none at all. Chamber (throats) cut with dull reamers can take considerably longer to break in. If the barrel is shooting good and deposits little copper, it is broke in."
I have the highest respect for Mr. Allens' opinions. I believe he said it best. "The most important thing is that you actually break the barrel in"
Jim
