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View Full Version : Barrel break in...Chrome lined vs. Non chrome lined


Ding126
09-22-2008, 6:37 AM
Need some feed back on barrel break in. I was told it's not necessary on a chrome lined barrel.

aplinker
09-22-2008, 6:50 AM
Proper break-in
TRRahHX9Zkg

:D

ohsmily
09-22-2008, 7:18 AM
Don't use a special procedure to break in your barrel. Just shoot it. Even for people who believe in barrel "break in," it doesn't apply to chrome lined barrels.

BigBamBoo
09-22-2008, 7:23 AM
............

Ding126
09-22-2008, 8:05 AM
There are LOTS of opinions on barrel break in.

Some say just shoot the gun...others (myself included) use the fire and clean method.

I have personally seen a rifle that was just shot and not cleaned for about 300rds.....and it shot great great...for awhile.
After about 300rds the groups started opening up....and now no matter what he tries the rifle has not ever shot as it did (sub MOA).

I guess it is all on what you want or expect from the rifle....I am a target/match shooter....I try and get every shot into the same hole.

If you are a hunter or tactical match shooter then this will not be as important to you.

Again...me...I break in my barrels with shoot one shot...clean..shoot,etc. for the first 20rds. Then shoot five shots and then clean for the next 20-40rds.

This has worked for me with all my rifle's. The cleaning and how you do it is another topic....but if you can get a bore scope you will know if your doing it right or not.
Carbon is the biggy...most think it is the copper they need to get out (and you should also)...copper collects towards the end of the barrel...carbon right past the chamber...again...a bore scope takes a lot of the guess work out of cleaning.

Take care,Stan

This may help your friend with MOA

http://www.superiorshootingsystems.com/

dilligaffrn
09-22-2008, 8:09 AM
Just shoot it.

C.G.
09-22-2008, 2:55 PM
Just shoot it.

+1.:)

NeoWeird
09-22-2008, 3:44 PM
Barrel break in has always sounded like urban myth to me. There is no logical reason why cleaning a rifle between shoots when it's new will increase it's accuracy, nor is there any reason why not cleaning it would harm it's accuracy. The very few "what if's" that come up, such as a burr gouging the bore if it weren't cleaned out are moot points IMO because if you are going to use a sub-quality barrel that has burrs of that size then you might as well not worry about accuracy at all. Fire lapping comes into play if shot excessively, but that is the case whether the barrel is new or old, so it being new is a moot point again.

I do know that I've heard straight from at least two different barrel makers (not big wigs, but they do enough that their name is passed around online on several forums) that they recommend barrel break in because the excessive damage caused by people who improperly clean the gun will result in increased business for them.

Also, most people who do barrel break in will not be able to explain HOW it works, just that it DOES. This is more because they would like to not feel like what they did was in vain or a waste of their time, money, etc. Unless you are buying from TOP tier barrel makers, varaiations in the steel alone will effect groups enough that one person's barrel who does or doesn't do a clean in process will shoot much differently than the next barrel made off the line that did the exact opposite and people will compare and argue for days over which is better, yet neither side can tell you WHY just that it IS.

Shoot the barrel and clean it properly when you need to. For an AR, run a lightly oiled patch through it every couple hundred rounds and spray the upper out with an adequate cleaner. Keep the internals lightly oiled as well - damp but not dripping.

bwiese
09-22-2008, 4:07 PM
Chrome-lined barrel: ensure it's clean/no bore obstructions (use patch with BreakFree/CLP then a dry patch) and go shoot the s**t outta it.

Don't use Hoppe's #9 or Hoppe's Copper whatever or any other ammonated bore solvents in a chrome-lined barrel - if you have, clean it out with another solvent very fast, very quickly.

M. Sage
09-22-2008, 4:19 PM
Need some feed back on barrel break in. I was told it's not necessary on a chrome lined barrel.

It's not needed on any barrel. Pre-clean the barrel to make sure there's nothing in it, and that the bore is dry, then go shoot it like you normally would.

Oh, I have heard stories about breaking in machine gun barrels, though... but that was to open up the groups on purpose.

kurac
09-22-2008, 4:20 PM
I have never tried to break a barrel in, I just make sure that I get a completly clean bore after each use, this can be 50-100 rounds per session. If someone can tell me how breaking in a barrel will effect the life or accuracy I might be interested.

glockk9mm
09-22-2008, 5:22 PM
I have never tried to break a barrel in, I just make sure that I get a completly clean bore after each use, this can be 50-100 rounds per session. If someone can tell me how breaking in a barrel will effect the life or accuracy I might be interested.


Exactly what I do too.

Ding126
09-22-2008, 5:31 PM
Thank you everyone. I have never broke in a barrel..but just recently come across people who have and do with bolt guns and 20+ inch AR barrels for long distance shooting..so It raised the question in my mind. Then a gun smith told me it wasn't needed on chrome lined barrels.

So I just wanted the knowledge of the forum to confirm whether I should or not.


If you google " David Tubbs " I'm sure you will gain some knowledge on barrel break ins. My smith told me some of his clients swear by it and his methods.

Thanks again everyone !!

ohsmily
09-22-2008, 6:46 PM
If you google " David Tubbs " I'm sure you will gain some knowledge on barrel break ins. My smith told me some of his clients swear by it and his methods.

Thanks again everyone !!


Well, there are plenty of people who swear by many things....that doesn't make them right. The value of barrel "break-in" is debatable even on super high end and accurate target barrels. It will certainly be an absolute waste of time and cleaning supplies to do it on anything but a highly accurate target barrel (and maybe a waste even in that example).

In light of Gale McMillan's and Dakota Rifle Company's recommendations, and the hassle that breaking-in entails, I don't do it anymore on any rifles, including my TRG-42.
http://www.6mmbr.com/GailMcMbreakin.html

http://www.snipercountry.com/Articles/Barrel_BreakIn.asp
If you don't know who Gale McMillan is, do a quick google search.

SuperSet
09-22-2008, 6:52 PM
+1.:)

Out of curiosity, I emailed White Oak Armament (WOA) a while back when I bought one of their 18" rifle-length barrels about this. Their response - 'Stop being OCD and just shoot it.' :)

Mail Clerk
09-22-2008, 7:17 PM
Need some feed back on barrel break in. I was told it's not necessary on a chrome lined barrel.


Ding126,

The instructions from my Bushmaster AR told me to shoot 200 rounds through the barrel to polish the bore even though it has a chromed bore. It said NOT to clean it in anyway until that 200 went through first. To clean too early will only delay the polishing process. Just push a clean patch before you cap bust. Take you time and don't over-heat the barrel.

In a conventionl/non chromed bore you have to go through the shoot n clean process to smooth out any imperfections in the lands of the rifleing.

My opinion, always get a chromed bore over the other.


Mail Clerk

NeoWeird
09-22-2008, 7:36 PM
In a conventionl/non chromed bore you have to go through the shoot n clean process to smooth out any imperfections in the lands of the rifleing.

My opinion, always get a chromed bore over the other.


Mail Clerk

Why would a conventional bore have more imperfections than a chrome lined bore? Bhrome will build relatively evenly when being plated so any imperfections in the finish will also be in the chrome, except chrome is MUCH harder than steel or stainless steel so it would take longer to polish out.

Chrome also tends to collect along edges so it will be more likely to create flared edges over a standard bore. Besides, if the clean and shoot method of barrel break in is to smooth out the barrel, then does it matter on our advanced rifling methods such as EDM and etching which have virtually no errors or imperfections?

5968
09-22-2008, 7:52 PM
Proper break-in
TRRahHX9Zkg

:D

I love his idea of breaking in a rifle. But I'm not so sure that I would lend him one of my guns...

C.G.
09-22-2008, 7:54 PM
If you google " David Tubbs " I'm sure you will gain some knowledge on barrel break ins. My smith told me some of his clients swear by it and his methods.



David Tubbs changes barrels like underwear and on top of that he has a lot of break in paraphernalia to sell you.;)

Mail Clerk
09-23-2008, 7:53 AM
NeoWeird,

In theory you are correct. My last statement is only based upon what the instruction book told me to do when first shooting my chromed barrel. Because AR's are not like bolt action rifles so even without a chromed barrel would involve too much dissembly of the rifle all the time. If you not into any competitions shooting then I can understand why anytype of barrel breakin is necessary. Combat rifles are what they are. If you don't get it with the first shot then you will with another.

Mail Clerk

motorhead
09-23-2008, 8:27 AM
barrel break in involves wear in of the rifling. important on match rifles as sightin will change slightly as barrel is broken in. chrome renders this moot as the hardness precludes any real wear for thousands of rounds.

darkest2000
09-23-2008, 8:49 AM
it's kinda like when I buy a new car and the dealer tells me how important it is to have an oil change after the first 1k mile or my engine won't perform or whatever blah blah blah.

Beelzy
09-23-2008, 8:49 AM
Cleaning is the one time when one can damage the rifling fairly easily.

Why in the heck would one want to clean a barrel so much??

The other good recipe for damage is "fire-lapping", I call it pre-wear.

xxdabroxx
09-23-2008, 10:29 AM
it's kinda like when I buy a new car and the dealer tells me how important it is to have an oil change after the first 1k mile or my engine won't perform or whatever blah blah blah.

Off topic, but.

you should change your oil after that first thousand miles. when engines are built they use engine assembly lube, and a camshaft lubricant that is actually abrasive. so after the camshaft is broken in fully the abrasive "lube" should be flushed out with fresh oil. this is not even taking into consideration any sand that could still be in any of the oil passages from the casting of the engine block.

so it seems the consensus is don't bother with breaking in a barrel.

jandmtv
09-23-2008, 10:36 AM
To each his own, I broke in my Rem700 SS 5R barrel, and it shoots .25" 5 shot groups at 100 yards. Would it shoot like this had I not properly broken in my barrel?, I dont know, but I dont want to find out either.

this is how I broke mine in (my own formula)

1 shot - clean, 10 times
3 shots - clean, 3 times
5 shots - clean, 2 times
10 shots - clean, 2 times

Mute
09-23-2008, 11:25 AM
Done the break-in thing and have gone the just shoot it route, with a number of rifles from service type rifles to precision rifles. Can't say I've found the broken-in rifles to shoot or clean any better than the ones that I just shot from the get go.

Beelzy
09-23-2008, 12:08 PM
To each his own, I broke in my Rem700 SS 5R barrel, and it shoots .25" 5 shot groups at 100 yards. Would it shoot like this had I not properly broken in my barrel?, I dont know, but I dont want to find out either.

this is how I broke mine in (my own formula)

1 shot - clean, 10 times
3 shots - clean, 3 times
5 shots - clean, 2 times
10 shots - clean, 2 times


Sorry to ruin your day, but my PSS went out with only a cleaning patch run
through it and shot one-hole groups with Federal Match ammo. I will admit
that having a good scope helps. ;)

CHS
09-23-2008, 1:15 PM
Here's the thing with barrel break-in. If someone could actually write up a concise article about WHY it helps your barrel, then I might be one to try it.

But no one has ever been able to explain just exactly how and why barrel break-in works. And most people that break-in barrels are the first to admit that they don't know if it works or not, they're just scared of not doing it.

Come on people! THINK!! Use those noggins!

Break-in is snake oil, pure and simple.

BigBamBoo
09-23-2008, 1:19 PM
............

Beelzy
09-23-2008, 1:34 PM
Nice groups.

I can only find one pic, but will this help?

Pardon the watch, I hang out on a watch forum as well. :D

http://i25.photobucket.com/albums/c82/beelzy/SubTarget.jpg

Ding126
09-23-2008, 1:42 PM
Those are some of the nicest groups I have seen in a while. Good Job!! I will just shoot my Ar's out of the box. And I will take the time to break in the high dollar, non chromed barrel. Better safe than sorry. IMO

NeoWeird
09-23-2008, 1:44 PM
You guys are confussing two completely different reasons on why precission target shooters clean their barrels so frequently. I will get to that in a minute.

As far as barrel break in wearing in the groves and lands; normal firing will do that too. So what you are saying is barrel break in is a process of rapid rifle wearing so you can get to a more consistant grouping faster; fine, I can believe that. However that does not mean that the rifle will be more accurate or the groupings better it simply means you will get to the point that your groupings are consistantly the same size faster - which also means you barrel will die as well as it's accuracy faster. That makes sense, but for someone like me who doesn't have to rush to that point, then there is no different end result. One method gets you there faster, one method has a higher round count life.

As for precission shooters cleaning their barrel frequently, it's because they are looking to remove as many variables as possible. Look at rail gun shooters - some of them clean their rifle every two shots. They clean the gun, fire to clean/dirty the barrel, let the barrel cool, take an aimed shot, repeat. They clean it so that their firearm is consistantly in the same condition and configuration as it was the last time they fired so shots are easier to predict and compensate for. It has nothing to do with barrel break in. It's about keeping their rifle in the same condition; which can't be done if they don't clean it and it gets dirtier and dirtier as they shoot it more.

And as for groups, I had a sub MOA Ruger 10/22 with a Clarke bull barrel that I did no break in for and I used it to varmint shoot PAST 125 yards quite often. Some claim it's just a lucky barrel from the lot. Some claim it would be better had I broken in - yet they can't give any reason why.

Barrel brake in is a myth. It's like "tactical". You slap tactical on anything, including repackaged ammo, and someone will swear it's better than stanard equipment. They can't explain to you why, but if it's "tactical" it must be to a higher standard than average gear (even if you are comparring Tapco tactical and Leupold optics).

I also like how the few guys supporting barrel break in can NOT give one explanation as to WHY it works, just that it DOES.

NeoWeird
09-23-2008, 1:46 PM
Those are some of the nicest groups I have seen in a while. Good Job!! I will just shoot my Ar's out of the box. And I will take the time to break in the high dollar, non chromed barrel. Better safe than sorry. IMO

Maybe you don't understand; cleaning DAMAGES your barrel more than firing it. So by doing a barrel break in, you are doing more harm than good. This may be wanted by people who shoot through guns and barrels like it's water, such as people who are sponsored and don't pay for them, but for the average joe you just shouldn't do it.

jandmtv
09-23-2008, 1:56 PM
Sorry to ruin your day, but my PSS went out with only a cleaning patch run
through it and shot one-hole groups with Federal Match ammo. I will admit
that having a good scope helps. ;)


Ruin my day? lol you are funny!

Beelzy
09-23-2008, 2:27 PM
Ruin my day? lol you are funny!


People tell me that all the time. :D

BigBamBoo
09-23-2008, 2:32 PM
.............

jandmtv
09-23-2008, 3:04 PM
And now that Photobucket started working again, here is a pic of a one hole group out of my 5R

http://i223.photobucket.com/albums/dd107/jandmtv/DSC02238.jpg

ohsmily
09-23-2008, 4:08 PM
And now that Photobucket started working again, here is a pic of a one hole group out of my 5R

http://i223.photobucket.com/albums/dd107/jandmtv/DSC0223.jpg

Ouch, guess it didn't. Fail on the link.

CHS
09-23-2008, 4:25 PM
What was explained to me back in the mid 90's by Knights Armament when I bought a Stoner SR-25 was that the barrel break in was to finish lapping the barrel.



Even if this is true and effective, I have a problem with any manufacturer selling extremely expensive precision rifles that aren't finished yet.

If they need to be finished, why won't the factory do it?

This means they are delivering to you a barrel that's only partly manufactured, and you get to finish the rest at home. That's absurd. I think this also gives more ammo to the "break in is snake-oil" camp.

NeoWeird
09-23-2008, 4:39 PM
Even if this is true and effective, I have a problem with any manufacturer selling extremely expensive precision rifles that aren't finished yet.

If they need to be finished, why won't the factory do it?

This means they are delivering to you a barrel that's only partly manufactured, and you get to finish the rest at home. That's absurd. I think this also gives more ammo to the "break in is snake-oil" camp.


It actually adds more than that. Filling in imperfections in the finish with copper should AID in accuracy. Why would you want to clean it out as soon as it forms? This is also why many older rifles need to "warm" up after being cleaned - they need to be shot a little so their imperfections of pitting, gouges, etc get filled in before they show their true potential.

And once again, of course Knights is going to recommend it - they are the only ones who sell (or did) SR-25 parts at the time. They want you to kill your barrel as fast as you can.

Also, even when done properly, cleaning is still more damaging to the barrel than shooting it alone by the simple nature of how you have to clean it.

BigBamBoo
09-23-2008, 5:26 PM
...............

M. Sage
09-23-2008, 5:26 PM
Off topic, but.

you should change your oil after that first thousand miles. when engines are built they use engine assembly lube, and a camshaft lubricant that is actually abrasive. so after the camshaft is broken in fully the abrasive "lube" should be flushed out with fresh oil. this is not even taking into consideration any sand that could still be in any of the oil passages from the casting of the engine block.

so it seems the consensus is don't bother with breaking in a barrel.

This is actually incorrect and on some cars, can lead to prolonged engine break-in. Audi is/was famous for using a different break-in fill on their cars (needed because Audi drivers don't drive hard enough to properly break an engine in on their own), and people changing oil at 1k were causing the rings to fail to seat, leading to oil consumption issues.

Buy a new car, take it out and do some full-throttle acceleration in 2nd or 3rd gear with the engine warmed up, letting it coast down and engine break each time. Do it about 10 times, and the rings are seated... which is 100% of the break-in process of a car.

Assembly lube isn't going to hurt an engine...

BigBamBoo
09-23-2008, 6:01 PM
............

Guntech
09-23-2008, 6:03 PM
Chrome-lined barrel: ensure it's clean/no bore obstructions (use patch with BreakFree/CLP then a dry patch) and go shoot the s**t outta it.

Don't use Hoppe's #9 or Hoppe's Copper whatever or any other ammonated bore solvents in a chrome-lined barrel - if you have, clean it out with another solvent very fast, very quickly.

I use Hoppe's No. 9 on all my guns. What would you recommend that works as good or better?

jandmtv
09-23-2008, 6:39 PM
Very nice group! The 5R's are shooters....I miss mine...but love my TRG-22. It was a trade off....wish I could have had both....maybe again one day.



Thanks, and thats before I installed a 1.5# Timney trigger and Tubb Speedlock. Im hoping those 2 will improve the groups further.

BigBamBoo
09-23-2008, 7:46 PM
...............

532Fastback
09-23-2008, 8:22 PM
Chrome-lined barrel: ensure it's clean/no bore obstructions (use patch with BreakFree/CLP then a dry patch) and go shoot the s**t outta it.

Don't use Hoppe's #9 or Hoppe's Copper whatever or any other ammonated bore solvents in a chrome-lined barrel - if you have, clean it out with another solvent very fast, very quickly.

What does the hoppes do?

jacques
09-23-2008, 8:38 PM
What does the hoppes do?

I am curious also, what does hoppes do to chrome?

Someone should do a study on barrel breakin. That would be interesting.

ohsmily
09-23-2008, 8:43 PM
[QUOTE=jandmtv;1552392]And now that Photobucket started working again, here is a pic of a one hole group out of my 5R

Very nice group! The 5R's are shooters....I miss mine...but love my TRG-22. It was a trade off....wish I could have had both....maybe again one day.

As far as saying cleaning will ruin a barrel...where is your proof of this? You keep saying that breaking in a barrel is BS...but there is NO proof on either camp....so where is your hard facts on cleaning.
Do you own a borescope?...without it you have no idea whats happening in your barrel.

You have yet to provide any proof except for your opinion....I have a old rifle (heavy barrel M70 22-250) with over 7000rds through it that was "broke in" and cleaned after everytime it was shot....that still shoots sub-moa.

Again....go with what works for you...just remember there is another side to each. I will stick with what works for me...and I believe in barrel break in. Untill there is HARD facts that prove otherwise....I will do it on my next rifle also.

Take care,Stan

It is clear that the rifles that you have owned shoot very well. The problem with your outlook is that you haven't NOT broken in a rifle. Thus, you have absolutely no idea if the rifles would have shot just as well if not better if you didn't do it. I am not saying your way is wrong. But, to say that your accurate rifles are evidence of the positive effects of break-in is not logically sound. Without something to compare to, your rifles have no evidentiary value other than "breaking in will not completely ruin your accuracy" because your rifles do shoot well. But, as I stated, they might shoot the same or better if you did not break them in....you don't know. I broke in my TRG-22 barrel and some other guns. Went through a lot of sweat and cleaning supplies doing it too. After doing some reading and not seeing an appreciable difference before and after breaking in, I have decided not to waste the HOURS at the range breaking in instead of focusing on load work-up and other practice.

jandmtv
09-23-2008, 9:28 PM
I used the Jewell Trigger at about 1.5-2lbs. in mine and the Tubb Speedlock firing pin and spring. I never shot it before I did all the work to it so I can not comment on how it shot as a stock rifle.

Take care,Stan

A few people told me to just get the whole assembly instead of the pin and spring. I was told it cuts lock time even more and its easier to install. I got mine from Brownells http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=24846&title=SPEEDLOCK%20FIRING%20PIN%20ASSEMBLY

The stock firing pin assembly weights 3.6oz (102g)
The Speedlock assembly weights 2oz (57g)

I hope it was worth the money.

aplinker
09-23-2008, 9:50 PM
Cleaning doesn't "wear" barrels. Improper cleaning can damage it.

I've yet to hear a single convincing argument (and not some hand waving voodoo with lots of technical jargon that's improperly used) for why to break in a barrel. I don't do it and won't until that happens.

motorhead
09-23-2008, 10:10 PM
i still maintain that it is impossible to break in a chrome lined barrel. chrome does not lap. ever tried to drill anything chromed? what happened to the bit? any imperfections in the rifling just cut into the jacket of the bullet.

Mail Clerk
09-24-2008, 7:39 AM
motorhead,

I agree with you in your respect. My instruction manual from Bushmaster said to shoot the rifle 200 rounds just to POLISH the bore. Besides in a combat semi auto rifle is different from a rifle designed to shoot competition.

Mail Clerk

Comstock Lode
09-24-2008, 8:03 AM
Lot of hoopla... Got a Rem 700 5R, did essentially the same as this guy, essentially same result. Needed? Who knows. Do we care? No.
"To each his own, I broke in my Rem700 SS 5R barrel, and it shoots .25" 5 shot groups at 100 yards. Would it shoot like this had I not properly broken in my barrel?, I dont know, but I dont want to find out either.

this is how I broke mine in (my own formula)

1 shot - clean, 10 times
3 shots - clean, 3 times
5 shots - clean, 2 times
10 shots - clean, 2 times"

motorhead
09-24-2008, 8:21 AM
i broke in my ak by firing 200rds. of wolf mil classic and cleaning the next day.

DrjonesUSA
09-24-2008, 3:26 PM
Need some feed back on barrel break in. I was told it's not necessary on a chrome lined barrel.



I believe that the late Gale McMillan was quoted as saying that barrel break-in is a load of BS and unnecessary.

532Fastback
09-25-2008, 8:25 PM
How do you improperly clean a barrel and what does hoppes 9 do to chrome?

aplinker
09-25-2008, 8:34 PM
How do you improperly clean a barrel and what does hoppes 9 do to chrome?

Ammonia can etch chrome.

Crown damage is the biggest issue with cleaning. Bore scratching can happen, from improper cleaning tools, cleaning rods, etc.

532Fastback
09-26-2008, 6:06 AM
Ammonia can etch chrome.

Crown damage is the biggest issue with cleaning. Bore scratching can happen, from improper cleaning tools, cleaning rods, etc.

oh ok and there is ammonia in hoppes 9.

NRAhighpowershooter
09-26-2008, 3:36 PM
The amount of ammonia in Hoppes is so miniscule it will never hurt a barrel... Industrial ammonia is only 20%. Ammonia floor cleaners are 0.2% ammonia. I have read the Sweets is 5% ammonia (but state it is non-acid)

CHS
09-26-2008, 4:18 PM
I have read the Sweets is 5% ammonia (but state it is non-acid)

ALL ammonia is non-acid, because ammonia is a base :)

ar15barrels
09-26-2008, 8:46 PM
If someone could actually write up a concise article about WHY it helps your barrel, then I might be one to try it.

http://www.kriegerbarrels.com/Break_In__Cleaning-c1246-wp2558.htm

Barrel brake in is to lay down any remaining reamer marks in the throat and bore.

M. Sage
09-26-2008, 8:50 PM
Seems like precision barrel makers would be using better reamers than to leave marks...

ar15barrels
09-26-2008, 9:08 PM
Seems like precision barrel makers would be using better reamers than to leave marks...

ALL reaming leaves marks, no matter how good the reamer is.

Better barrel makers hone or lap the bore before rifling.
That still does not fix the throat.
It's not possible to ream the throat without cutting across the direction of bullet travel.
The throat can be EDM'd though and no break-in will be necessary.
Another thing that's done is to electro polish.
I have never heard of extrude-hone being used on barrels, but that would also work good.

M. Sage
09-26-2008, 9:52 PM
Extrude Hone would loosen up the bore, though.

I know about cutting tools and the marks left behind. We used to use roller burnishers at the last factory job I worked at, and I still had to worry about the finish staying in spec.

ar15barrels
09-26-2008, 9:59 PM
Extrude Hone would loosen up the bore, though.

That's ok, as long as you started with an undersized groove diameter.

drclark
09-26-2008, 10:08 PM
Assuming for the moment that barrel-break-in does have some measurable effect on the accuracy of a match rifle, it probably won't have any noticeable effect on a chrome-lined barrel.

From what I have read (and I am by no means an expert), barrels that are to be chrome-lined are slightly over-bored (.224 for a .223 cal for example) and that the chrome lining will then fill in the last .001 or so. The problem is that the chrome lining process cannot ensure an exact uniform coating of the bore, leaving high and low spots. Hence, chrome lining generally is a detriment to accuracy in lieu of improved reliability, durability and ease of cleaning. Thus, chrome lining is typically used in military applications but rarely in hunting or target rifle applications.

So, if you've got a chrome lined bore, I wouldn't bother with the breakin process. If your rifle is for plinking or you are satisfied with 1.5-2.0 MOA performance, it probably isn't worth the trouble either. Generally, you'll probably get better improvement in groups by reloading your own ammo than you would with the breakin process.

If you are looking for deep-sub MOA groups, then you can probably debate whether or not the breakin process is worth the time and effort.

drc

ar15barrels
09-26-2008, 10:14 PM
From what I have read (and I am by no means an expert), barrels that are to be chrome-lined are slightly over-bored (.224 for a .223 cal for example) and that the chrome lining will then fill in the last .001 or so. The problem is that the chrome lining process cannot ensure an exact uniform coating of the bore, leaving high and low spots. Hence, chrome lining generally is a detriment to accuracy in lieu of improved reliability, durability and ease of cleaning. Thus, chrome lining is typically used in military applications but rarely in hunting or target rifle applications.

Correct for the most part.
The chrome is only about 0.0002" to 0.0004" thick though.
They start with a regular size barrel, ETCH the bore and chamber, then chrome plate to replace what was etched away.
Neither the etching process or the chrome process are 100% consistent.

Guntech
10-01-2008, 2:57 PM
The amount of ammonia in Hoppes is so miniscule it will never hurt a barrel... Industrial ammonia is only 20%. Ammonia floor cleaners are 0.2% ammonia. I have read the Sweets is 5% ammonia (but state it is non-acid)

+1 Its all myth that it ruins your barrels IMO.

BigBamBoo
10-01-2008, 7:41 PM
..................

ohsmily
10-01-2008, 10:34 PM
Here is some info from some of the top barrel makers...argue with them...tell them you do not need to break in their barrels...

http://www.bartleinbarrels.com/BreakInCleaning.htm

http://www.pac-nor.com/care/

http://www.kriegerbarrels.com/RapidCat/catalog/pagetemplate.cfm?template=/RapidCat/common/viewPage.cfm&PageId=2558&CompanyId=1246

Gale McMillan was as respected in the field as anyone else. He states that it is a money-making ploy that barrel makers use so you wear your barrel out quicker and hence need a new one sooner. That addresses what you linked to. Did you ever bother reading the article he wrote about it?

But, you have had good luck with the process, so keep doing it...but, you haven't NOT done it so you have nothing to compare it to.

BigBamBoo
10-02-2008, 7:06 AM
.............

M. Sage
10-02-2008, 12:45 PM
I believe that McMillan was retired when he wrote about the uselessness of break-in...

saki302
10-02-2008, 3:45 PM
Once he was retired, didn't he have less to gain from folks wearing out their barrels faster through excessive cleaning? :D

I doubt you could wear a barrel faster by not cleaning it enough- eventually you will get dirty enough to affect accuracy, but a PROPER cleaning takes care of that.

-Dave