Barrel Break in Procedure

tdhanses

Senior Member
Joined
Sep 26, 2018
Messages
3,261
That’s interesting on the rpm, never really considered it but ran the calcs and I’m good with my 6.5cm at 243k and 300wsm at 266k.
 

bigmike23

Junior Member
Joined
Apr 10, 2020
Messages
16
There's no such thing as barrel break in. It's bore conditioning. You are filling in the microscopic grooves in the metal with the copper coming off the bullet. A soft bullet could never ever change the much harder barrel without blowing up the gun on the first shot. Just like you can rub your nail against your phone screen for eternity, you're never going to scratch it. Just shoot your gun, have fun, and clean occasionally when groups open up. I find mineral spirits or hoppes works best. Makes the gun smell beautiful too
 

CO-AJ

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Apr 23, 2020
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277
Location
Colorado
On my precision 6mm Creed Bartlein barrel I cleaned once before shooting. Then did 3 rounds with a wet patch, then 5 rounds with a wet patch, then 10 rounds and a wet patch. Really I was looking for any green (copper) residue on the patch. For all that effort I really had no green, just the usual black and 1-2 wet patches followed by a dry patch and it was sparkling clean. Now I dont clean while shooting, but all my rifles that were used get cleaned after a day at the range or in the field.
 

zion zig zag

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Joined
May 16, 2020
Messages
367
I haven't read the whole thread so apologies if it's been covered, but saw the barrel cleaning procedure from Bartlein on the first page. I recognize that they know more about barrels then I ever will, so there must be a reason. But can a nylon brush really damage the crown? It seems like you'd have to push/pull the brush through an incredible amount of times for it to have any effect?

From Bartlein:
"If you use a brush, we recommend one caliber smaller or an old worn out one. Roll a patch around the brush. Always push the brush, Breech to Muzzle. Remove the brush before pulling your rod back through! NEVER pull the brush back over the crown. More damage to a good barrel is done from cleaning than actual shooting. The first to suffer is the crown. The crown is the last thing the bullet touches when it leaves the gun. Any damage here affects accuracy no matter what."
 

bigmike23

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Apr 10, 2020
Messages
16
I haven't read the whole thread so apologies if it's been covered, but saw the barrel cleaning procedure from Bartlein on the first page. I recognize that they know more about barrels then I ever will, so there must be a reason. But can a nylon brush really damage the crown? It seems like you'd have to push/pull the brush through an incredible amount of times for it to have any effect?

From Bartlein:
"If you use a brush, we recommend one caliber smaller or an old worn out one. Roll a patch around the brush. Always push the brush, Breech to Muzzle. Remove the brush before pulling your rod back through! NEVER pull the brush back over the crown. More damage to a good barrel is done from cleaning than actual shooting. The first to suffer is the crown. The crown is the last thing the bullet touches when it leaves the gun. Any damage here affects accuracy no matter what."
A bullet moving at 3500 fps with extraordinary heat and pressure behind it does no damage whatsoever to the crown, yet somehow a brush pulled back through causes damage? BS
 

B23

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Aug 17, 2017
Messages
226
Location
NW
I haven't read the whole thread so apologies if it's been covered, but saw the barrel cleaning procedure from Bartlein on the first page. I recognize that they know more about barrels then I ever will, so there must be a reason. But can a nylon brush really damage the crown? It seems like you'd have to push/pull the brush through an incredible amount of times for it to have any effect?

From Bartlein:
"If you use a brush, we recommend one caliber smaller or an old worn out one. Roll a patch around the brush. Always push the brush, Breech to Muzzle. Remove the brush before pulling your rod back through! NEVER pull the brush back over the crown. More damage to a good barrel is done from cleaning than actual shooting. The first to suffer is the crown. The crown is the last thing the bullet touches when it leaves the gun. Any damage here affects accuracy no matter what."
I, think, and it makes sense, is that potentially carbon deposits can get in to the bristles and cause damage by pulling the brush back through the barrel. There are probably other factors but I can see that as being a concern.
 

Frank Green

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Apr 19, 2021
Messages
23
A bullet moving at 3500 fps with extraordinary heat and pressure behind it does no damage whatsoever to the crown, yet somehow a brush pulled back through causes damage? BS
I call BS back! The amount of damage we see and the one part of the barrel that takes the most abuse that we see is the muzzles crown. Not just pulling a brush back over the crown but when guys drag a steel rod over the crown as well.

Can't tell you the number of barrels over the years...that all I did for the customer was recrown it and the accuracy was fixed/came right back.

Yes it's been argued....the bronze brush is 80 on the BHN scale and the barrel is 280ish. So yes the steel is harder...but as the old saying goes...why can water erode rocks! The water is softer than the rock so how can it be? One is repetition. Also the hard carbon particles can get trapped in the bristles...the hard carbon particles will also scratch the bore as well. I see signs of it all the times. You will see faint/slow twist marks going over the tops of the lands. This is from the bristles of the brush and or rod drag or a combination of both.

Goes back to the picture I also posted of the damage to the bore done with an abrasive cleaner. The abrasive cleaner in conjunction with the brush will amplify what is going on.

Also goes back to what I say....if you have a system/procedure you use to clean the gun and your not wrecking anything...I've got nothing to say. Also it doesn't mean the guy next to you is doing it better.

Also heat and pressure....I've seen the wear to the crown just from the gases exiting the bore of the barrel. We call it....gas cutting. That's why any barrel we do finish work on...we machine a 60 degree chamfer on the bore edge. This helps with the gas cutting effect as well as damage from shooters pulling the brush back over the crown edge as well. This was proven years ago. Even before Obermeyers time. Ever wonder why this is spec'd out on all the gov't test barrel drawings? It's on every single one that I can think of seeing.
 

Frank Green

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Apr 19, 2021
Messages
23
As far as bullet wear causing wear in the barrel....I would never thought of that.....but it's direct information I've gotten from the bullet/ammo makers. They are the guys shooting not just a 40 or 50 rounds in a day but they are shooting hundreds of rounds in a day doing testing. They are doing the cleaning....and they keep more accurate data in terms of round count, type of powder being used, type of bullets being used as well.

Also direct data that I've seen first hand at Gov't test facilities. It was really eye opening when I seen 5.56 accuracy test barrel where they fired the SS109 (mild steel core bullets) and or tracer ammo thru them. A 5.56 barrel where they will use it for 2500 rounds of accuracy testing....if they run the mild steel core bullets and or tracer bullets thru it....they said the barrel is good for 1000 rounds of accuracy testing and they have to pull it. If the rifling would cut thru the jacket of the mild steel core bullets...the steel core beats up the rifling big time. So when I was shown this we got into the discussion of bullets and wear...and the response was most definitely thte type and length of bullets etc...can be a factor in barrel life.
 

Frank Green

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Apr 19, 2021
Messages
23
Then someone has to come up with a better explanation or a way to describe....why the throat does wear and polish in from shooting?

Same goes with the bore being worn away. I've got cut aways of barrels with known round counts etc..I have got 308win accuracy test barrels where the lands/rifling are completely gone for the first .200" of the throat area when the original freebore length was only .085". The wear also extends up from there for about 5" or even more. No abrasives where used in the cleaning of these barrels.

I use these cut aways for training and teaching so people can see what it really looks like inside of a barrel.

I'll say it's a combination of heat, pressure as well as wear from the bullets/friction. Not to mention possible cleaning as well.
 

grappling_hook

Senior Member
Joined
Dec 15, 2019
Messages
129
Location
Alaska
I call BS back! The amount of damage we see and the one part of the barrel that takes the most abuse that we see is the muzzles crown. Not just pulling a brush back over the crown but when guys drag a steel rod over the crown as well.

Can't tell you the number of barrels over the years...that all I did for the customer was recrown it and the accuracy was fixed/came right back.

Yes it's been argued....the bronze brush is 80 on the BHN scale and the barrel is 280ish. So yes the steel is harder...but as the old saying goes...why can water erode rocks! The water is softer than the rock so how can it be? One is repetition. Also the hard carbon particles can get trapped in the bristles...the hard carbon particles will also scratch the bore as well. I see signs of it all the times. You will see faint/slow twist marks going over the tops of the lands. This is from the bristles of the brush and or rod drag or a combination of both.

Goes back to the picture I also posted of the damage to the bore done with an abrasive cleaner. The abrasive cleaner in conjunction with the brush will amplify what is going on.

Also goes back to what I say....if you have a system/procedure you use to clean the gun and your not wrecking anything...I've got nothing to say. Also it doesn't mean the guy next to you is doing it better.

Also heat and pressure....I've seen the wear to the crown just from the gases exiting the bore of the barrel. We call it....gas cutting. That's why any barrel we do finish work on...we machine a 60 degree chamfer on the bore edge. This helps with the gas cutting effect as well as damage from shooters pulling the brush back over the crown edge as well. This was proven years ago. Even before Obermeyers time. Ever wonder why this is spec'd out on all the gov't test barrel drawings? It's on every single one that I can think of seeing.

Frank, what is your experience with the effectiveness of folks who use the at-home chamfering solution of putting a brass screw in an electric hand drill with valve grinding compound to touch up and lightly chamfer (not full recrown) the inside edge of the crown? Has it worked okay, damaged/worsened accuracy, or been a quick cure for accuracy issues that you've seen? I imagine someone like you would always use the best tool for the job-- and that many of the ones you've seen might be screw-ups that people bring to you to fix-- but wondering if you have experiences to share.

Thank you for your contributions, it's great to see you on this forum.
 

CO-AJ

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Joined
Apr 23, 2020
Messages
277
Location
Colorado
A bullet moving at 3500 fps with extraordinary heat and pressure behind it does no damage whatsoever to the crown, yet somehow a brush pulled back through causes damage? BS
i dont pull it back through because I just pushed the crud out. I unscrew the brush once clear of the crown and pull the rod back through with nothing on it. I also use a chamber guide at the breech.
 
Joined
Apr 14, 2021
Messages
6
Whether it's truth or myth, it's a fun little tradition that I look forward to with every new rifle purchase. Crack a brew and spend an hour out in the middle nowhere getting familiar with your new rifle. And you just invested $1K, $2K, $3K+ in the the damn thing so even if there is the slightest benefit to doing the break in procedure why the hell not do it?
 

bird35

Member
Joined
Jun 29, 2020
Messages
63
Clean it really good when you get it and then shoot until accuracy starts to drop. I have had some that took a really long time to get clean the first time. I have also followed manufacture suggested break in on some such as Howa and accuracy as well as ease of future cleaning was no different than on barrels i did not break in.
 

Frank Green

Junior Member
Joined
Apr 19, 2021
Messages
23
Frank, what is your experience with the effectiveness of folks who use the at-home chamfering solution of putting a brass screw in an electric hand drill with valve grinding compound to touch up and lightly chamfer (not full recrown) the inside edge of the crown? Has it worked okay, damaged/worsened accuracy, or been a quick cure for accuracy issues that you've seen? I imagine someone like you would always use the best tool for the job-- and that many of the ones you've seen might be screw-ups that people bring to you to fix-- but wondering if you have experiences to share.

Thank you for your contributions, it's great to see you on this forum.
I still say the best way to crown a barrel is by doing it in the lathe. Either by single point cutting it or a piloted tool. The only thing you have to be careful about with a piloted tool is make sure you have the proper bushing size fitted. Plenty of cutting oil. The chamfer we cut on the crown's bore edge for a size comparison is about the land width of the rifling when you look into the bore. You don't need anymore than that. What you want is no burr left at the bore edge and the chamber to be even/concentric all the way around.

I'm not fond of the brass screw, in a drill and polishing compound. If it works for you......as it does for some run with it.

After crowning the barrel take a Qtip and drag it around the bore edge. If it's pulling fibers off you most likely have a burr. First round fired will break this burr away and not leave you with a decent crown edge in my opinion and cause issues. The issue can be mild....or worse.

The type or style of crown to me isn't important. I've shot them all and depending on the rifle....it's what I run/have on it. I have the sporter style, Marine Corp style, stepped recess, 11 degree and flat style but all have the chamfer on the bore edge.
 

Kimber7man

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Joined
Jun 18, 2019
Messages
780
Location
Hamilton County, Indiana
Frank,
Regarding pulling the brush back into the bore from the crown, do you have any comparative data on damage to the crown using nylon bristle vs. bronze bristle brushes?
Thanks
 

buildyourown

Newbie
Joined
Apr 25, 2021
Messages
9
Location
Flatlander
Frank,
Thank you for taking the time to educate us with your years of experience. New member and I am new to the precision bolt world but just picked up my new rifle, complete with a Bartlein 3B barrel in 300wsm. I am very much looking forward to getting intimate with this rifle for an upcoming fall hunt and gleaning all the info I can absorb, thank you!
 

Frank Green

Junior Member
Joined
Apr 19, 2021
Messages
23
Frank,
Regarding pulling the brush back into the bore from the crown, do you have any comparative data on damage to the crown using nylon bristle vs. bronze bristle brushes?
Thanks
No I have no data that supports the nylon brush causing any issues per say in regards to the crown.

I would still refrain from using any abrasive cleaner even with the nylon brush.

I would also regularly clean the nylon brush off. Try to make sure no carbon particles/deposits are laying in the brush. The hard carbon will scratch the bore as well.
 
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