Barrel break in, or not ?
- Thread starter dpopl8r
- Start date
Im no gun smith, but the way i look at it is if you bought a brand new bike, Yamaha R1 lets say, are you going to go out and just pin it off the rev limiter and do wheelies and bag on it when it has 40 kms on it?
I know its different, but it took me an hour, its broke in, now I can bag on it!
I know its different, but it took me an hour, its broke in, now I can bag on it!
.330Dakota
CGN Regular
- Location
- Northeastern ON
Just shoot it. As far as the bike or any other engine, two heat cycles and an oil change and its good to go.
- Location
- Somewhere on the Hudson Bay Coast
TDC said:
The ridges left from the chambering reamer lie across the lay of the lapped barrel steel. When a bullet passes across those microscopic ridges, thin strips of bullet metal are removed from the bullet, which then form a plasma in the hot propellant gases behind the bullet, and are deposited as fouling along the length of the barrel.
The fact that fouling decreases after a break-in regimen leads one to believe that there is merit to the exercise. I do not see how this could be done mechanically only to the chamber area without distorting the chamber. Therefore, shooting followed by a gentle cleaning between rounds, then between groups, and treating the barrel with a penetrating oil such as Kroil or Gun Juice as you proceed, seems to be a sensible way to get the best results from an expensive custom barrel.
"Four easy steps:
a) Order Microlon GunJuice (I can point you in the direction of some if need be)
b) Shove a patch soaked in said solvent down the barrel
c) Shoot once, shove a patch with Juice down the barrel
d) Repeat x10. Barrel is now broken in."
I am also getting on the Microlon Gun juice bandwagon. Reduced friction so barrel life is noticeably increased and muzzle velocity is increased too.
With Stainless barrels Microlon says that the above cycle may have to be repeated up to 20 times. Other advice given is to make sure that you shoot immediately after applying the juice when the barrel is still wet.
As you go through the process the bullets will hit the target a little higher each time (so I've heard, haven't tried it yet but will when my rifle gets here). This is from the increase in muzzle velocity. After 10 applications (around 20 for stainless barrels) the bullets will all start to group in the same place, once they stop climbing up your target you know that the barrel has been treated.
Supposed to be a one time deal but some guys use it after every range session and some after every 500rds. Micorlon says that's not necessary but more Juice will not hurt anything.
a) Order Microlon GunJuice (I can point you in the direction of some if need be)
b) Shove a patch soaked in said solvent down the barrel
c) Shoot once, shove a patch with Juice down the barrel
d) Repeat x10. Barrel is now broken in."
I am also getting on the Microlon Gun juice bandwagon. Reduced friction so barrel life is noticeably increased and muzzle velocity is increased too.
With Stainless barrels Microlon says that the above cycle may have to be repeated up to 20 times. Other advice given is to make sure that you shoot immediately after applying the juice when the barrel is still wet.
As you go through the process the bullets will hit the target a little higher each time (so I've heard, haven't tried it yet but will when my rifle gets here). This is from the increase in muzzle velocity. After 10 applications (around 20 for stainless barrels) the bullets will all start to group in the same place, once they stop climbing up your target you know that the barrel has been treated.
Supposed to be a one time deal but some guys use it after every range session and some after every 500rds. Micorlon says that's not necessary but more Juice will not hurt anything.
JNG said:
I think this is a contradiction...
... if friction is reduced, the pressure will be reduced as well as the velocity reduced. That is why moly coated bullets have a lower velocity than bare bullets using the same load. I don't think you can reduce the friction and pressure and at the same time increase the velocity.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Boomer, the firing of a shot during a break in is mechanically removing those rough spots. That's why the process requires repeated cleaning. You want that bullet rubbing on the metal surface, not fouling, wearing down the rough spots.
That same thing will happen if you just shot the barrel normally (just takes a bit longer) or if you used a lapping/polishing compound like JB bore brite or if you firelap. I prefer the JB method as it takes a few minutes and adds no additional wear to the rest of the pipe.
Guntech, I am sure you know the concept is to reduce bore friction so more of the powder's energy is used in accelerating the bullet, not going into friction produced heat.
And like you, I find that it doesn't really work out that way. I use alot of moly and have found it reduced pressures due to bore friction. yes, velocities were lower MOST of the time for a given powder charge.
In many instances, I could go faster, with more powder of course, and maintain accuracy (the rougher the barrel the more prevalent this was). I believe that every barrel has a sweet spot which is tied to pressure. If you can reduce friction, you stand a chance of getting more velocity before it hits max pressure.
The most graphic example was a WWI Lee Enfield with the typical rough bore. Using uncoated 150gr Hornady Interlocks, I was getting serious pressure signs at 2500 to 2550fps. With coated bullets, I easily hit 2650fps with excellent accuracy.
Jerry
That same thing will happen if you just shot the barrel normally (just takes a bit longer) or if you used a lapping/polishing compound like JB bore brite or if you firelap. I prefer the JB method as it takes a few minutes and adds no additional wear to the rest of the pipe.
Guntech, I am sure you know the concept is to reduce bore friction so more of the powder's energy is used in accelerating the bullet, not going into friction produced heat.
And like you, I find that it doesn't really work out that way. I use alot of moly and have found it reduced pressures due to bore friction. yes, velocities were lower MOST of the time for a given powder charge.
In many instances, I could go faster, with more powder of course, and maintain accuracy (the rougher the barrel the more prevalent this was). I believe that every barrel has a sweet spot which is tied to pressure. If you can reduce friction, you stand a chance of getting more velocity before it hits max pressure.
The most graphic example was a WWI Lee Enfield with the typical rough bore. Using uncoated 150gr Hornady Interlocks, I was getting serious pressure signs at 2500 to 2550fps. With coated bullets, I easily hit 2650fps with excellent accuracy.
Jerry
Boomer said:
That appears to make sense. My next question is this. If small deposits of the bullet jacket are left behind and form a plasma. How does a simple liquid cleaning product remove these deposits? On another note, there seems to be a large following who do not do any sort of barrel break in and still seem to print excellent groups? So one would have to ask, does barrel break-in really make that big a difference?
Here's a little something I found online.
http://www.snipercountry.com/Articles/Barrel_BreakIn.asp
Mr. McMillan is indeed THE McMillan. Just something to think about. Then again I'm the kind of guy who shoots factory ammo out of convenience so barrel break in and any potential gain in accuracy isn't a large concern.
TDC
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
TDC, IF copper is 'burnt' off then redeposited, it goes on the bore as a plating.
When you use a chemical solvent, you are dissolving that metal...literally. Why I choose copper removers with heavy ammonia content.
Personally, I feel that the copper that is on the bore comes from friction. A bit may burn off but at the very high rate it takes to vaporize a metal, it will solidify very quickly (flame front is actually very quick and short).
How does that explain all the copper at the muzzle of some of my bores?
The surface texture of a bore is like a cheese grater and just grinds off a smidge of material as the bullet races by. That is why some rough bores shoot great after some fouling shots - all those rough spots get filled in.
Another reason I suggest not cleaning your barrel until it tells you to. My Stevens 200 in 223 has now digested over 90rds without any cleaning and drove the last five shots into the same 3/8ish MOA group at 100yds yesterday. Might swab the bore today cause I am feeling guilty.....
I am sure if you used JB long enough (arms like Popeye or have a few weeks with nothing to do) you would wear down the edges of the rifling. But then you would now get POLYGONAL rifling which is a rifling profile to increase velocity due to reduced bullet engraving.
See told you JB use could be a good thing.
For those who fear that JB could actually be used to wear down a bore, here is a simple test. Get some 1000 to 1200grit sandpaper and start sanding the outside of a barrel. With some effort you will start to get a very shiney spot. I bet it took you way longer then 20 revolutions.
Now keep sanding away and see how long it takes to remove any significant amount of metal. I bet you quit long before that happens and you now have a mirror like shiney spot.
The fouling in a very badly fouled barrel can be removed with JB in 20 to 50 strokes. A rough and pitted pipe usually a few minutes. You are not going to wear down anything. It works great.
As for changing the bore surface that was lapped in by the barrel maker, me thinks the first 50rds fired made sure that surface is changed permanently.
Jerry
When you use a chemical solvent, you are dissolving that metal...literally. Why I choose copper removers with heavy ammonia content.
Personally, I feel that the copper that is on the bore comes from friction. A bit may burn off but at the very high rate it takes to vaporize a metal, it will solidify very quickly (flame front is actually very quick and short).
How does that explain all the copper at the muzzle of some of my bores?
The surface texture of a bore is like a cheese grater and just grinds off a smidge of material as the bullet races by. That is why some rough bores shoot great after some fouling shots - all those rough spots get filled in.
Another reason I suggest not cleaning your barrel until it tells you to. My Stevens 200 in 223 has now digested over 90rds without any cleaning and drove the last five shots into the same 3/8ish MOA group at 100yds yesterday. Might swab the bore today cause I am feeling guilty.....
I am sure if you used JB long enough (arms like Popeye or have a few weeks with nothing to do) you would wear down the edges of the rifling. But then you would now get POLYGONAL rifling which is a rifling profile to increase velocity due to reduced bullet engraving.
See told you JB use could be a good thing.
For those who fear that JB could actually be used to wear down a bore, here is a simple test. Get some 1000 to 1200grit sandpaper and start sanding the outside of a barrel. With some effort you will start to get a very shiney spot. I bet it took you way longer then 20 revolutions.
Now keep sanding away and see how long it takes to remove any significant amount of metal. I bet you quit long before that happens and you now have a mirror like shiney spot.
The fouling in a very badly fouled barrel can be removed with JB in 20 to 50 strokes. A rough and pitted pipe usually a few minutes. You are not going to wear down anything. It works great.
As for changing the bore surface that was lapped in by the barrel maker, me thinks the first 50rds fired made sure that surface is changed permanently.
Jerry
I don't mean to pick on you mysticplayer but you did read the post in the article that stated "anyone who uses JB voids their warranty..." Somehow I think a guy who produces custom tubes and is very successful at it, might have a better idea about the affects of JB and barrel break-in than any of us do... As long as you don't see a loss in accuracy than to each his own.
Does anyone know if the USMC, US Army, Canadian Army, or any other known faction use a barrel breakin process or do they just shoot them as well?
TDC
Does anyone know if the USMC, US Army, Canadian Army, or any other known faction use a barrel breakin process or do they just shoot them as well?
TDC
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
TDC, there is at least one barrel maker that voids the warranty if you use a brush to clean. I think they are just being a litte too conservative. But it keeps their claims down.
The use of JB is now widespread in the BR ranks, especially in the big boomers. Many will clean every 200rds or so just to make sure that any carbon build up at the throat is removed and it keeps that area as smooth as possible.
I am sure there are some that cringe when I say I use conc ammonia in my barrels. However, it does the job in very little time so the actual time of exposure in my case, is less then a weaker solution that might be left overnight or a few days.
You are right, as long as the barrel shoots well, it's all good. And also illustrates how there is no absolute when it comes to barrel care.
I just cleaned my 223 Stevens after shooting over 100rds. I think many would clean before that but it showed no drop in accuracy and there was absolutely no copper during cleaning (conc ammonia used). I cleaned it mostly because I was curious.
Don't think I will be cleaning that pipe anytime soon.
Jerry
The use of JB is now widespread in the BR ranks, especially in the big boomers. Many will clean every 200rds or so just to make sure that any carbon build up at the throat is removed and it keeps that area as smooth as possible.
I am sure there are some that cringe when I say I use conc ammonia in my barrels. However, it does the job in very little time so the actual time of exposure in my case, is less then a weaker solution that might be left overnight or a few days.
You are right, as long as the barrel shoots well, it's all good. And also illustrates how there is no absolute when it comes to barrel care.
I just cleaned my 223 Stevens after shooting over 100rds. I think many would clean before that but it showed no drop in accuracy and there was absolutely no copper during cleaning (conc ammonia used). I cleaned it mostly because I was curious.
Don't think I will be cleaning that pipe anytime soon.
Jerry
- Location
- Somewhere on the Hudson Bay Coast
Mystic -
The last 100 yard group I shot for accuracy with my Kreiger/McMillan/Remington .308 I had difficulty measuring, but I think I got it right. The largest outside measurement was .412" from which I subtracted .308" and got a group size of .104". I offer this not to brag, but as evidence that a clean barrel will shoot. I would of been happy with any group under a half inch, but I'll take this. I will not claim that I can shoot groups this small on demand, but a clean barrel produced that group never the less.
I think I have a theory which may explain why our experience may differ. If the interior surface of a factory barrel is rough, it might become smoother once it is fouled, and the carbon from the burnt powder deposited on top of the copper fouling might work as a dry lubricant which prevents galling of the subsequent bullet as it passes through the bore.
This is not the case with a lapped bore, which when fouled becomes less smooth, and because the interior dimensions of a high quality barrel are of tighter tolerances, there is no relief for a bullet as it passes through the bore, so any significant build up of jacket material in the bore will cause galling of the bullet, which proves detrimental to accuracy.
I think any manual manipulation of the bore or chamber with a cleaning rod, brush and abrasive material must be viewed as less precise than the straight line passage of a bullet, bearing equalling on all contact surfaces, and aided by 60,000 pounds of pressure. Subsequent cleaning with only patches soaked in a copper dissolving solvent, followed by dry patches before the solvent can dry is benign, and will have no ill effect on the interior dimensions of the barrel or chamber.
The fact that copper fouling is present at the muzzle is evidence of a plasma being formed, and the platting occurs as the distance from the chamber increases. If the barrel is short enough that a muzzle flash is visible, there will be particles of copper suspended in that flame.
Perhaps an experiment could be conducted where a thin metal target could be fired at, from a few inches or a foot from the muzzle of the rifle. If I am right, copper wash will be evident around the bullet hole.
The last 100 yard group I shot for accuracy with my Kreiger/McMillan/Remington .308 I had difficulty measuring, but I think I got it right. The largest outside measurement was .412" from which I subtracted .308" and got a group size of .104". I offer this not to brag, but as evidence that a clean barrel will shoot. I would of been happy with any group under a half inch, but I'll take this. I will not claim that I can shoot groups this small on demand, but a clean barrel produced that group never the less.
I think I have a theory which may explain why our experience may differ. If the interior surface of a factory barrel is rough, it might become smoother once it is fouled, and the carbon from the burnt powder deposited on top of the copper fouling might work as a dry lubricant which prevents galling of the subsequent bullet as it passes through the bore.
This is not the case with a lapped bore, which when fouled becomes less smooth, and because the interior dimensions of a high quality barrel are of tighter tolerances, there is no relief for a bullet as it passes through the bore, so any significant build up of jacket material in the bore will cause galling of the bullet, which proves detrimental to accuracy.
I think any manual manipulation of the bore or chamber with a cleaning rod, brush and abrasive material must be viewed as less precise than the straight line passage of a bullet, bearing equalling on all contact surfaces, and aided by 60,000 pounds of pressure. Subsequent cleaning with only patches soaked in a copper dissolving solvent, followed by dry patches before the solvent can dry is benign, and will have no ill effect on the interior dimensions of the barrel or chamber.
The fact that copper fouling is present at the muzzle is evidence of a plasma being formed, and the platting occurs as the distance from the chamber increases. If the barrel is short enough that a muzzle flash is visible, there will be particles of copper suspended in that flame.
Perhaps an experiment could be conducted where a thin metal target could be fired at, from a few inches or a foot from the muzzle of the rifle. If I am right, copper wash will be evident around the bullet hole.
