New Barrel Break-in And Cleaning Methods

jdmecomber

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Jan 23, 2016
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How do you factor in the number of rounds fired through a barrel by the manufacturer before you get it? I have a Remington 700 Long Range in .30-06. It came with the 20-20 digital scope and the claim that it would hit out to 500 yards right out of the box. It did but then Remington stop producing the ammo so I have swapped out the scope. No information was provided as to how many rounds went down the barrel before it was shipped. I have put about 50 rounds down range with it and am getting sub MOA groups. What ideas do you have for people like me?

I have no idea how many rounds the manufacturer puts down the tube. I would guess very few.
 

J E Custom

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10,599
Location
Texas
I have no idea how many rounds the manufacturer puts down the tube. I would guess very few.

It depends on how the test goes, normally they shoot 3 to 5 rounds for function, unless it is a custom shop gun and/or a match rifle that has a MOA guaranty and they must shoot a group.

Ether way they don't clean the bore between shots, so no break in has actually started.

J E CUSTOM
 
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Russ661

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Lancaster, California
Forgive me if I’m wrong but it was stated earlier that part of the break in process was the filling of micro pores in the barrel with copper deposited when a round is fired. If that is correct then the break in process was indeed started when the first round was fired, was it not?
 

J E Custom

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Forgive me if I’m wrong but it was stated earlier that part of the break in process was the filling of micro pores in the barrel with copper deposited when a round is fired. If that is correct then the break in process was indeed started when the first round was fired, was it not?
Actually the break in process removes any irregularities in the bore surface using the bullet. the copper fouling is removed each time it is fired to make the bore surface more uniform, the copper fouling will ****** this process buy protecting these irregularities unless removed building up around or near the imperfections.

A quality hand lapped barrel will take far less shoot and clean steps because most of these imperfections have been removed by the lapping. Unless the temperature is allowed rise to a very hot temperature there will be no migrating in to the metallurgy of the barrel and the copper fouling will be a surface problem only.

The filling of imperfections that can't be removed by brake-in are called seasoning and this is done by allowing some of the copper fouling to remain to fill these voids. this works on barrels that have less than an ideal internal finish.

J E CUSTOM
 
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Russ661

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Ether way they don't clean the bore between shots, so no break in has actually started.

J E CUSTOM
The filling of imperfections that can't be removed by brake-in are called seasoning and this is done by allowing some of the copper fouling to remain to fill these voids. this works on barrels that have less than an ideal internal finish.
J E CUSTOM
I did not know there are different stages of
the break-in process; I was under the impression that a barrel was either broken in or it wasn’t and I assumed (apparently incorrectly) that the break-in process began with the first bullet down the pipe. I learn something new every time I come to this website.

‘Seasoning’ as you describe it is a new concept to me but I can see how that would work. Will a less than ideal barrel’s performance continue to improve until the optimal amount of ‘seasoning’ is deposited?
 

J E Custom

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I did not know there are different stages of
the break-in process; I was under the impression that a barrel was either broken in or it wasn’t and I assumed (apparently incorrectly) that the break-in process began with the first bullet down the pipe. I learn something new every time I come to this website.

‘Seasoning’ as you describe it is a new concept to me but I can see how that would work. Will a less than ideal barrel’s performance continue to improve until the optimal amount of ‘seasoning’ is deposited?

It is a combination of both break-in and seasoning on a less than optimum bore finish. A factory barrel will need more brake-in and sometimes never totally remove imperfections left by tooling. These barrels will sometimes shoot there best when clean but as they foul, they become more consistent and the results are better long term accuracy. At some point though, they will need some amount of cleaning to regain the accuracy.

A barrel that is properly lapped and broke-in will normally shoot it's absolute best clean but as you fire it without cleaning the accuracy will start to degrade at some point and it should be cleaned or allowed to go to the "seasoned" condition for consistency. Which ever method you subscribe to, be sure and do your load workup in that state. (I subscribe to the clean bore system and clean after each test load to test the difference in different loads Apples to Apples).

I posted a test #20 that shows the advancement of brake-in as you shoot more and more rounds cleaning as you go. If a non clean method is used It will take many more shots or copper seasoning to reach consistency because the defects are still there and will always collect copper fouling in the same areas.

https://www.longrangehunting.com/threads/new-barrel-break-in-and-cleaning-methods.160450/page-2

Many people season there barrels, especially if they shoot matches where cleaning during the match is near impossible. If a good break-in is done fouling will be less and seasoning can be more consistent.

PS: We "all" can learn something on this site as long as we keep an open mine.:cool:

J E CUSTOM
 

Alibiiv

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Hello Len, thanks for the great write up on barrel cleaning. You wrote that you do not recommend ammonia based bore cleaners, is TETRA consider an ammonia based cleaner. I use Tetra bore cleaner to clean out my Whelen and .358 Win due to using Barnes bullets, now I'm concerned about harming the barrels. I also read about the Tipton bore guides, I just recently purchased a Hornady bore cleaning guide, should I scrap it and go to a Tipton instead, $14 or $20 is not going to make that much difference it it protects my barrel if one considers the cost of a rebarrel. After cleaning my barrels I always use a product called RIG that I put on a nylon brush and swab the barrel quite heavily with it to prevent rust, am I doing any harm to the barrel with this procedure. Thanks again your posts are always informative and great to read.
 

Litehiker

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One caveat on "barrel break-in".
IF you have a FULLY chrome lined barrel (as found in some military semi-automatic rifles) then bore break-in is unnecessary. The chrome lining is very smooth and fairly tough as it is meant to be a bore protection.

Cleaning for carbon buildup is the most important type of cleaning for chrome lined barrels, especially for semi-auto rifles where the round count between cleanings is often very high.

Eric B.
 

nicholasjohn

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Feb 12, 2019
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Vancouver, WA
I am a big believer in barrel break in for many reasons as discussed in the past.

The benefits in reduced fouling along with longer barrel life and faster load work up make it worth while in my opinion.

But today, I wanted to see if there were any more benefits to barrel brake in so I performed a test that I had not seen anything about it and this is the results.

I built myself a 260 AI using a 788 rem action and a 3 groove Lilja varmint contour barrel.

The loads were fire form loads in the middle of the 260 loading using a 123 Hornady match bullet.

The test was to chronograph the fire form loads as I did a breakin of the barrel to see if there were any changes in velocity during this process.

Here are the velocity readings.
Clean barrel
1st shot = 2790 ft/sec
clean barrel
2nd shot = 2808 ft/sec
clean barrel
3rd shot = 2831 ft/sec
clean barrel
4th shot = 2854 ft/sec
clean barrel
5th shot = 2868 ft/sec
clean barrel
6th shot = 2878 ft/sec
clean barrel
7th shot = 2890 ft/sec
clean barrel
8th shot = 2894 ft/sec
At this point the barrel appeared to be broke in because it cleaned up well and velocity seemed to remain close to 2890 ft/sec with SDs below 8.

There was no point to figuring SDs during break in because the velocity kept climbing but once it settled down SDs were good (Especially for fire forming loads)

Velocities during break in had a 104 ft/sec total spread but once break in was finished, the average velocity improvement over the first round was averaging 80 to 85 ft/sec faster than the first shot in the new barrel.

This was just one test and i am sure some barrels will exceed this improvement if break in is done correct and some will not, but it does show me that there is another advantage to doing a breakin beside less fouling.

I don't know what a barrel would do if it was not broken in, or when or how many shots it would take before it would reach its average max velocity from the first shot.

NOTE: All loads were as exactly the same as I could load them, so I feel the test was valid and at least I learned something from it.

J E CUSTOM
I am really glad that I read your post. I'm going to the range next week with a new rifle and a new chronograph. Had I just gone out and shot a string like you just posted here, I might have thought that I had bought a chronograph that was faulty. This post has saved me a lot of frustration, as well as given me a way to determine when a new barrel is broken in. I won't find myself fussing about things that aren't problems. After the velocity readings become consistent, I'll know that what I'm doing with my loading is causing the results I see. Thanks a million.
 

jshepherd61

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Joined
Dec 28, 2015
Messages
147
Location
Parker
I am a big believer in barrel break in for many reasons as discussed in the past.

The benefits in reduced fouling along with longer barrel life and faster load work up make it worth while in my opinion.

But today, I wanted to see if there were any more benefits to barrel brake in so I performed a test that I had not seen anything about it and this is the results.

I built myself a 260 AI using a 788 rem action and a 3 groove Lilja varmint contour barrel.

The loads were fire form loads in the middle of the 260 loading using a 123 Hornady match bullet.

The test was to chronograph the fire form loads as I did a breakin of the barrel to see if there were any changes in velocity during this process.

Here are the velocity readings.
Clean barrel
1st shot = 2790 ft/sec
clean barrel
2nd shot = 2808 ft/sec
clean barrel
3rd shot = 2831 ft/sec
clean barrel
4th shot = 2854 ft/sec
clean barrel
5th shot = 2868 ft/sec
clean barrel
6th shot = 2878 ft/sec
clean barrel
7th shot = 2890 ft/sec
clean barrel
8th shot = 2894 ft/sec
At this point the barrel appeared to be broke in because it cleaned up well and velocity seemed to remain close to 2890 ft/sec with SDs below 8.

There was no point to figuring SDs during break in because the velocity kept climbing but once it settled down SDs were good (Especially for fire forming loads)

Velocities during break in had a 104 ft/sec total spread but once break in was finished, the average velocity improvement over the first round was averaging 80 to 85 ft/sec faster than the first shot in the new barrel.

This was just one test and i am sure some barrels will exceed this improvement if break in is done correct and some will not, but it does show me that there is another advantage to doing a breakin beside less fouling.

I don't know what a barrel would do if it was not broken in, or when or how many shots it would take before it would reach its average max velocity from the first shot.

NOTE: All loads were as exactly the same as I could load them, so I feel the test was valid and at least I learned something from it.

J E CUSTOM
I use a similar procedure developed by Bartlein Barrels and also monitor progress with a chrono. Bartlien is a big fan of SWEETS 7.62 to remove the copper fowling between the first three shots. A lot of Smith’s do not like it because it is very caustic if not used properly. I’ve found it to work excellent if used properly to remove all copper fowling. I tend to not leave it in longer than 3 minutes before neutralizing it with WD40 although it recommends letting it set 5-10 minutes.

Bartlein Barrels, Inc.

Break in and Cleaning

The age old question? "Breaking in the New Barrel", Opinions vary a lot here, and this is a very subjective topic!

For the most part, the only thing you are breaking in is the throat area of the barrel.
The nicer the finish that the Finish Reamer or Throating Reamer leaves, the faster the throat will break in.

List of cleaning items:
• Hopps #9 solvent
• Sweets 7.62 copper solvent
• Nylon brush
• Patch jag
• Caliber specific cotton patches
• WD40
• Dewey’s cleaning rod
• Bore Guide

1. Shoot one round and clean for the first two rounds individually. Following this cleaning procedure:
a. Run a patch with Butch’s Bore Shine
b. Run a dry patch
c. Run a patch with Sweets 7.62 copper removing solvent on a nylon brush (keep patch for comparison between groups)
d. Wait 5 minutes
e. Run 3 dry patches (keep patches for comparison between groups)
f. Run a patch with WD40 (to naturalize the ammonia in the Sweets 7.62)
g. Run a dry patch
h. Run a Patch with Hopps #9
i. Dry with patches
j. Repeat steps h and I, until clean
k. Run a patch of Butch’s Bore Shine
l. Run dry patches

2. Look to see what the barrel is telling you.

a. If I'm getting little to no copper out of it, I sit down and shoot the gun. Say 4 ¬ 5 round groups, cleaning between groups. If the barrel cleans easily and shoots well, we consider it done.

3. If the barrel shows some copper or is taking a little longer to clean after the first two, shoot a group of 3 rounds and clean following steps a through l.

4. Then a group of 5 and clean.


5. After you shoot the 3rd group and 5th group, watch how long it takes to clean.

a. Also notice your group sizes. If the group sizes are good and the cleaning is getting easier or is staying the same,

6. Then shoot 4 ¬ 5 round groups cleaning in-between each group. If fouling appears to be heavy and taking a while to clean, notice your group sizes.

a. If group sizes are good and not going sour, you don't have a fouling problem.

7. Some barrels will clean easier than others. Some barrels may take a little longer to break in.

a. Remember the throat. Fouling can start all the way from here. We have noticed sometimes that even up to approximately 100 rounds, a barrel can show signs of a lot of copper, but it still shoots really well, and then for no apparent reason, you will notice little to no copper and it will clean really easy.

8. This is meant as guide lines only.
a. There is no hard and fast rule for breaking in a barrel.

9. Cleaning Always use;

a. a good quality, 1 piece cleaning rod (such as Dewey, Boretech, etc...).

b. Always use a bore guide. Whether cleaning a bolt action rifle or a semi¬auto.

i. Good bore guides and cleaning rods are available from a number of sources (such as Sinclair International, Champions Choice, Brownell's, etc...).

ii. We prefer to use the Parker¬Hale/Dewey’s type cleaning Jags.

iii. Cut your patches to the proper size.

iv. If the patch squeaks going down the barrel, it is to tight.

v. Roll your patches around the jag tip like a cigarette. This gives an even patch versus poking the patch in the center. When you use the latter method the patch doesn't fold evenly. Using the first method of rolling the patch, gives you more surface area and keeps the tip of the cleaning rod centered going down the barrel.

vi. 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!

vii. 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.

viii. Cleaning Basics: Good 1 piece quality cleaning rod. Bore guide Nice cotton patches Don't drag the brush back over the crown!

ix. Never mix your solvents! Either in a jar or in the barrel, unless you are a chemist and know how they are going to react with one another and with the steel.
 

sw282

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Joined
Dec 29, 2015
Messages
151
About 20 yrs ago l worked for Kenny Jarrett @ Jarrett Rifles in Jackson, SC.. One of the more unpleasant duties was barrel break-in. His procedure was to shoot one, then clean for the first 10rds. Second 10rds was shoot two, then clean... His favourite solvents were Sweets and Kroil. We had a couple shop rifles used for fire form a couple of calibers not available... l don't remember those ever getting cleaned...

During break-in the rifles had no sights mounted or any final finish applied. We just shot from the shoulder ''shotgun'' style... lts amazing how easy it is to shoot accurately from the standing position with just a bit of practice.. On that range @ 300yards is a 12'' metal swinger of Armor Plate an inch thick... We could hit that 12'' gong from a standing position most of the time shooting shotgun style...
 

timblevins

Active Member
Joined
Mar 4, 2015
Messages
32
I posted this elsewhere in an existing discussion thread but I think it would be helpful to have as a stand alone contribution to the subject. Keep in mind, if you ask 100 barrel makers or rifle builders for their advice on the subject, you'll get many opinions. This is just mine based on lots of study and on my own rifle and shooting experience.

*************************************************************

Here is my take on the subject...and what I give my rifle customers as advice. This is for hand lapped, match grade barrels, not factory gun barrels.




Long Range Rifles, LLC
Cleaning Instructions



Cleaning Equipment:
Dewey one-piece cleaning rods, jags and brushes are recognized throughout the industry as the very best. I recommend and use them. A properly fitted bore guide is a must and there are many good ones available such as the Tipton Universal bore guide. Bore Tech Eliminator is a non-ammonia copper solvent that we also use for its fast effective copper removal. Under certain conditions ammonia based cleaners can harm a rifle's bore. So we do not recommend their use. Iosso Bore Paste is the only abrasive paste we recommend, and it is for the specific occasional use of removing a carbon build-up in your barrel. Like any abrasive, over-use will damage your barrel. So read more about its use in the general cleaning section below.

Barrel Break-in:
We know that a custom barrel like the Brux Barrels we use at Long Range Rifles break-in faster than factory/production barrels. So what exactly is a broken-in barrel? A barrel is broken-in at the point where it has obtained its maximum accuracy, minimum copper fouling and stabilized velocity readings.

The process of break-in is initiated by shooting just 3-5 rounds and then cleaning your rifle's barrel to remove the copper fouling. Normally repeating this step 2-3 more times will complete the process of reducing copper fouling. During this process, you will notice the barrel is cleaning much easier at every step. With 3-4 cleanings after 3-5 rounds each in the first 25 rounds, go ahead and use the rifle normally, as this part of break-in is complete.

Do not use any abrasive paste type cleaners during break-in as doing this can damage your rifle’s bore.

Regarding the aspect of stabilizing velocities, the use of chronographs and experience will show that the barrels tend to speed up over the first 50 to 100 or so rounds, with the exact same load being used during that time period. What does this mean to the average marksman? First understand that your rifle’s long range trajectories will change slightly at some point during the first 50-100 rounds. Second, if you’re doing load development early on in the barrel’s life, (less than 50 rounds) don’t max out your pressure or velocity. You may be well over pressure when you hit the 100+ rounds fired mark, caused by a possible velocity increase of up to 75 fps.
At the 75 to 100 round mark, your barrel will now be ready for its first general cleaning.


General Cleaning and Maintenance:
Regular cleaning and maintenance will keep your rifle running its best. This outline is by no means the only way to maintain a rifle. But if you are unfamiliar with the process, this is a good outline to guide you in the right direction.

Make sure your Firearm is unloaded before cleaning.

In general, keep your rifle free of dust and grit build up. Simply wipe off the bolt and swab out the receiver with cloths and q-tips, using a commercial gun cleaner designed for general grime. Similarly, wipe down the outside of your firearm as well. Compressed air also works well for removing dust and debris. Inspect and clean your bolt face with solvent and q-tips, paying particular attention to removing any brass flakes or debris build up around the ejector and extractor. Light oil on a hand towel works great for wiping down your rifle and keeping it looking new. Keep your bolt lugs lubed with a small amount of bolt grease such as TM Ultra and Montana X-Treme. This will help keep the rifle well lubed and prevent bolt lug galling.

Rifle bore cleaning is necessary to keep your rifle shooting accurately. Each cartridge designated rifle may require different cleaning intervals depending on such things as: bullet bearing surface length, bullet velocity, over-bore capacity, cleanliness of propellant used, rate of fire, etc. Normally, experience has shown that anywhere from 100 to 300 rounds are within reason for the frequency of cleanings. Cartridges like the 308 Winchester can go as high as 500 under certain circumstances. Always clean from breach to muzzle.

For general bore cleanings, remove your rifle's bolt and insert a bore guide through your rifle's receiver. Using a properly sized jag covered with a patch, apply Bore Tech Eliminator to the patch and push it through the bore. Always clean from breach to muzzle. This will soften up the majority of bore fouling. Follow this up by running a properly sized bronze or nylon brush through a wet bore for 5-6 stokes. This will help to loosen up stubborn copper and carbon fouling. (Recently I switched to nylon brushes since bronze brushes can give you false positives on the presence of copper fouling.) Continue with more wet patches of Bore Tech Eliminator once every 5 minutes, until your patches come out clean, or with just a faint tint of blue. Usually only two or three wet patches sessions is needed.

Once you are satisfied your bore is free of copper fouling, dry out the bore with some clean patches. If you wish, you can run a wet patch of oil thru the bore, followed by a dry patch to remove the excess oil. This is also a good idea if you plan on storing the gun for a period of time before shooting it again. Make sure you swab out your chamber. I use a bore swab such as the one included in the inexpensive Tipton Action and Chamber Cleaning Kit. It includes a chamber swab and a lug recess cleaning tool. Applying a small dab of quality grease (such as TM Ultra or Montana X-Treme) to your bolt lugs after every cleaning to help to prevent bolt lug galling.

Never fire your rifle without first running a dry patch down your bore to insure you have no bore obstructions, or excessive oil in your barrel.

I always fire two “fouling shots” before I hunt with a recently cleaned barrel – or rely on a shot for sighting in. You will note that the point of impact may be off as much as ½ inch at 100 yards within the first two shots.

Persistent Carbon Fouling
At about every 300-500 rounds fired, we recommend cleaning out any carbon build up in your bore. This can be seen with a bore scope, if available. Or this may be needed if you have an unexplained degradation of accuracy. Carbon typically builds up in the first 1-12 inches of your bore. So this is the area that must be cleaned.

First, clean your barrel with the above outlined procedure for a general bore cleaning, to remove copper fouling. Now we can begin to remove the carbon build up. Iosso Bore Paste may be the most effective way available to remove carbon build up. Iosso Bore Paste is a mild abrasive paste. Coat a patch with a layer of paste, and using a jag and bore guide, push the jag into the first 6 inches of bore, from the chamber end, and stroke the area 3-4 times back and forth. Then stroke out to 12 inches 2-3 times, working back and forth from chamber to 12 inches out.

Lastly, push the patch all the way out the barrel with no back and forth strokes past the 12 inch mark. The patch will be black. This is a reaction with the paste and barrel steel. Don’t assume you need to repeat this procedure. Doing it just once has proven to remove 90% of carbon fouling. Now using bore cleaner and jagged patches, push a multitude of patches wet and dry through the bore to remove any and all remaining paste, and once again swab out the chamber.

Over-use of any abrasive in a custom barrel will damage the bore, so follow these instructions carefully and do not overuse.

Firing pin and internal bolt cleaning is best accomplished by a certified gunsmith, special tools may be required for the removal of the firing pin assembly from the bolt. All Long Range Rifles are properly lubed at the shop. If you experience problems with your rifle's bolt and firing pin assembly or have exposed your rifles bolt to excessive dirt, grit or water, have your bolt internals cleaned and lubricated immediately.

Trigger cleaning is normally accomplished by removing the barreled action and spraying lighter fluid or alcohol into the mechanism and then blowing dry with compressed air. Using oil in a trigger can cause a buildup of dust and sludge leading to a possible malfunction. Keep your triggers clean and dry for best results.

Muzzle Brake Cleaning
Carbon build up in a muzzle brake can cause a degradation of accuracy when the buildup gets heavy. Clean your brakes at regular intervals. If you feel a muzzle accessory is causing an accuracy issue, remove it and test fire your gun to eliminate it as a possible source. Soaking and brushing seem to be the preferred method of brake cleaning.

Be careful not to damage your rifle's crown when cleaning muzzle accessories.


Long Range Rifles, LLC


***********************************
.
 

timblevins

Active Member
Joined
Mar 4, 2015
Messages
32
Wow thank you for that information. That was really detailed and put together well for ease of instruction. Much appreciated.
 

J E Custom

Well-Known Member
Joined
Jul 29, 2004
Messages
10,599
Location
Texas
I am a big believer in barrel break in for many reasons as discussed in the past.

The benefits in reduced fouling along with longer barrel life and faster load work up make it worth while in my opinion.

But today, I wanted to see if there were any more benefits to barrel brake in so I performed a test that I had not seen anything about it and this is the results.

I built myself a 260 AI using a 788 rem action and a 3 groove Lilja varmint contour barrel.

The loads were fire form loads in the middle of the 260 loading using a 123 Hornady match bullet.

The test was to chronograph the fire form loads as I did a breakin of the barrel to see if there were any changes in velocity during this process.

Here are the velocity readings.
Clean barrel
1st shot = 2790 ft/sec
clean barrel
2nd shot = 2808 ft/sec
clean barrel
3rd shot = 2831 ft/sec
clean barrel
4th shot = 2854 ft/sec
clean barrel
5th shot = 2868 ft/sec
clean barrel
6th shot = 2878 ft/sec
clean barrel
7th shot = 2890 ft/sec
clean barrel
8th shot = 2894 ft/sec
At this point the barrel appeared to be broke in because it cleaned up well and velocity seemed to remain close to 2890 ft/sec with SDs below 8.

There was no point to figuring SDs during break in because the velocity kept climbing but once it settled down SDs were good (Especially for fire forming loads)

Velocities during break in had a 104 ft/sec total spread but once break in was finished, the average velocity improvement over the first round was averaging 80 to 85 ft/sec faster than the first shot in the new barrel.

This was just one test and i am sure some barrels will exceed this improvement if break in is done correct and some will not, but it does show me that there is another advantage to doing a breakin beside less fouling.

I don't know what a barrel would do if it was not broken in, or when or how many shots it would take before it would reach its average max velocity from the first shot.

NOTE: All loads were as exactly the same as I could load them, so I feel the test was valid and at least I learned something from it.

J E CUSTOM

A few months back I posted this and wanted to follow up with another test that was similar only using a much less powerful cartridge to see if the results were similar.

The cartridge was a 22 WMR with a new custom barrel.

After each shot, the barrel was cleaned and another shot followed. each shot was chronographed to try and identify when the barrel was broken in and if there was any advantage to a break in on such a small caliber.

Shot number and velocity.
1 = 1883
2 = 1893
3 = 1929
4 = 1944
5 = 1948
6 = 1950
7 = 1961
8 = 1970
9 = 1977
10 = 1981
11 = 1979
12 = 1984
13 = 1982
14 = 1977

The last 4 shots seemed to level out and shot an average of 1980.5 for an average velocity increase of 97.5 ft/sec over the first round. NOTE: the ammo used was factory 40 grain CCI and was not very consistent and with large SD after brake in.
while testing the 30 grain Vmax, group size and velocity greatly improved with a SD of 21 and a top velocity of 2307 ft/sec.

I have to try the 45 grain ammo and see if it will do anything for SD s And accuracy.
The best groups achieved during these test were just over 1/2 MOA @ 100 yards with the 30 grain ammo.

Most rim fire (LR) ammo Is held to a SAMMI standard of 4 % deviation in velocity, the 22 WMR is only held to 10 % and this is the reason that the WMR does not shoot as accurately as Other Rim Fire ammo. I couldn't find the SAMMI spec. for the 17 HMR
for comparison.

So once again I find brake in a valuable tool to season your barrel for early velocity gains and load development.

J E CUSTOM
 
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