Barrel Break in
- Thread starter bootlaceb
- Start date
Hey hang on a second!
Some stainless match barrels need hardly any break-in, but going straight into shooting strings on others will lead to serious copper fouling problems, and equally serious hard work in subsequently removing it.
Yes, it's true that good barrel blanks are lapped (polished) as a final step after boring and rifling, but the need for barrel break-in comes from the chamber throat. The reamer inevitably leaves tiny grooves in the throat at 90-degrees to the bore / bullet travel, and that's what you're running in with a break-in procedure. There are a few manufacturers / gunsmiths who polish these out, but they're an exception to the rule.
Your first few bullets remove this slight roughness, but lose some jacket material in the process. Some of this is left in the area just ahead of the chamber and with powder fouling will make a hard ring if left there. Most of the lost copper is vapourised and pushed down the bore by the powder gases eventually condensing on the relatively cool section in the last few inches behind the muzzle, where it's clearly visible to the naked eye.
The usual procedure is to clean after each shot using a strong copper remover. You normally find patches come out a really dark blue for the first five or six, then a couple with less colouring, then virtually none in which case you can reckon you're done, maybe just decoppering after fair size strings if still needed.
However, every barrel / chambering job is an individual and anybody who deals with a lot of new barrels finds the running-in requirement varies enormously. While some stop coppering after three of four shots, others suffer from the problem for up to 100 rounds. In the latter case, a 1-shot/clean regime is impractical. so the procedure is to use it for the first 10 shots maybe, then afterwards after some strings of five, then 20 or 25.
Sure you can ignore all this, but the risk is a heavily fouled barrel that won't clean properly, and which doesn't deliver full accuracy.
While an absolute pain in the rear, shoot/clean doesn't stop you doing load development. I've had some superb groups from brand new barrels undergoing this process.
Laurie,
York, England
Some stainless match barrels need hardly any break-in, but going straight into shooting strings on others will lead to serious copper fouling problems, and equally serious hard work in subsequently removing it.
Yes, it's true that good barrel blanks are lapped (polished) as a final step after boring and rifling, but the need for barrel break-in comes from the chamber throat. The reamer inevitably leaves tiny grooves in the throat at 90-degrees to the bore / bullet travel, and that's what you're running in with a break-in procedure. There are a few manufacturers / gunsmiths who polish these out, but they're an exception to the rule.
Your first few bullets remove this slight roughness, but lose some jacket material in the process. Some of this is left in the area just ahead of the chamber and with powder fouling will make a hard ring if left there. Most of the lost copper is vapourised and pushed down the bore by the powder gases eventually condensing on the relatively cool section in the last few inches behind the muzzle, where it's clearly visible to the naked eye.
The usual procedure is to clean after each shot using a strong copper remover. You normally find patches come out a really dark blue for the first five or six, then a couple with less colouring, then virtually none in which case you can reckon you're done, maybe just decoppering after fair size strings if still needed.
However, every barrel / chambering job is an individual and anybody who deals with a lot of new barrels finds the running-in requirement varies enormously. While some stop coppering after three of four shots, others suffer from the problem for up to 100 rounds. In the latter case, a 1-shot/clean regime is impractical. so the procedure is to use it for the first 10 shots maybe, then afterwards after some strings of five, then 20 or 25.
Sure you can ignore all this, but the risk is a heavily fouled barrel that won't clean properly, and which doesn't deliver full accuracy.
While an absolute pain in the rear, shoot/clean doesn't stop you doing load development. I've had some superb groups from brand new barrels undergoing this process.
Laurie,
York, England
zullo74 said:
I no longer break in quality match grade barrels; I go right into load development. I use a bore scope to monitor wear, firecracking, cleaning technique, etc. There is nothing I've seen by looking through the scope that lends any credibility to breaking in a match grade barrel that has been hand lapped.
Lou Baccino
LA50SHOOTER
Sworn To Protect The Constitution.
I Fully concur with Laurie on this matter. - I've worked with custom barrels from .22 caliber up through .50 BMG Improved over a 30 year period.
And yes, the barrels of today are very good indeed when it comes to final finish but as Laurie has pointed out it's that chamber throat leade area that prompts me to take certain steps on Any Barrel that is new. - When I receive a new barrel I always clean it before putting it into service. And I never fire a shot on a 100% squeaky clean bore (ever) I have a very slight amount of bore conditioning oil on the bore (usually about 1-2 drops on each side of the clean patch I push through depending on the caliber. - After the very first round is fired I clean the bore, I get every bit of copper fouling out of it before I fire another shot. In over 60+ "custom" barrels (caliber doesn't seem to matter) I've never failed to find copper fouling after that very first shot. - Most barrels I do a fire 1 shot & clean for the first 5 shots & I'm taking note of how the barrel does & taking note of the fired brass coming out of the gun. (by taking note, Mic the head at .200 ahead of the bolt-face on the case & doing a visual inspection) Also, I'm usually chronographing the load to gather some data in that manner as well. - After I've run 5 & cleaned after each then I'll move on to a 3 shot group string & see what the barrel is "telling me". - This summer I broke in several barrels, I had one Broughton 1-11 tw. in 300 WSM that after 13 rounds had basically no significant copper fouling - To me the barrel was ready to go from a shooting/additional load development standpoint. - During the course of the day I did shoot Six 5 shot groups (30 rounds) before I cleaned it & received only the faintest amount of copper fouling back.
- Also, I clean what might be considered often by some folk's standards, I usually clean after 20 - 30 rounds or what would be shot in a relay with sighters. - I've seen .50 caliber barrels that never quit fouling especially shooting bronze monolithic solid bullets. They just seem to foul less after a period of time with regular cleaning. - I have one barrel in .338 Allen Magnum that still fouls very badly after 145 rounds, from the first shot onward & the accuracy is lousy from it. - I'm not going to mention the name of the provider of that barrel on the forum here as the owner of that company has already agreed that I can send it back & if there are issues they will address them & help make things right.
- I've noticed that a good barrel will usually either quit fouling or give up almost all of the desire to foul (in everything except big calibers) quite early on if the fire-one & clean regime is carried out in the very beginning. - Large bores & high velocity are a different situation to deal with especially if monolithic brass or copper bullets are used. (They just seem to foul less after a while which has been observed during a rigorous cleaning cycle of say shooting only a maximum of 20 rounds & then cleaning) -
- Ron -
Here is one other thing to keep in mind. Generally, a brand new barrel will speed-up and finally settle down long about 125 shots (in that vicinity somewhere).. I have had barrels speed up as much as 100 f.p.s. by the time it settles down. I have had them speed up as little as 20f.p.s. However, they normally settle in and the speed-up runs about 40-60f.p.s. So you CAN start load development right out of the starting gate, however, you will only get "some idea". Until that barrel stops speeding up, are you REALLY doing ACCURATE load development? So getting the barrel to stop "coppering up" is only the FIRST aspect of "breaking in" a barrel..
LA50SHOOTER
Sworn To Protect The Constitution.
Concur Ben - I saw that exact thing on a new 28 Nosler Benchmark barrel that I put into service last week - She started out at 3180 & settled in at around 3220 fps using an 86 gr. load of RE-33 with a 180 gr. Berger VLD at a +.005 jam - And she seems to want to shoot as well. (And yes that is 20 shots @ 200 yds)
I've seen several cases recently of very substantial pressure / MV rises after 125-200 rounds. It seems to be a recent phenomenon, but maybe we simply didn't notice a few years back with fewer chronographs around and milder loads.
I've come across two really significant examples over the last year or two, both sixes and (I think) Benchmark barrels. The first was a 6BR and definitely a Benchmark that produced staggering MVs and tiny groups with the Berger 105gn VLD immediately after run-in. The owner was cramming more Viht N150 into the case than most people would believe was possible (30-inch drop-tube on the powder funnel employed) and results were fantastic ..... for a while. Then it started blowing primers in the middle of a BR match forcing retirement. In subsequent testing, charges were dropped a half grain - no change; full grain - still no improvement; 1.5gn - still not sorted! In the end, I seem to remember it needed over a 2gn drop to get things OK again, but it never shot quite as well after the adjustments.
I've come across two really significant examples over the last year or two, both sixes and (I think) Benchmark barrels. The first was a 6BR and definitely a Benchmark that produced staggering MVs and tiny groups with the Berger 105gn VLD immediately after run-in. The owner was cramming more Viht N150 into the case than most people would believe was possible (30-inch drop-tube on the powder funnel employed) and results were fantastic ..... for a while. Then it started blowing primers in the middle of a BR match forcing retirement. In subsequent testing, charges were dropped a half grain - no change; full grain - still no improvement; 1.5gn - still not sorted! In the end, I seem to remember it needed over a 2gn drop to get things OK again, but it never shot quite as well after the adjustments.
LA50SHOOTER
Sworn To Protect The Constitution.
That Load was chosen based a little bit of analysis using quick-load & the fact that the rifle is running a 34" barrel. The RE-33 load computed at around 56K pressure after I adjusted the cartridge OAL parameter. - I have 2 barrels throated for the 180 gr. Bergers & 2 for the 195 gr. - By the way I tried the 183 gr, Sierra & I didn't get very good results with them jammed +.005 into the land using either RE-33 or Retumbo.
- My apologies for getting off topic -
That's an interesting point that Laurie made & I will watch for it in the Benchmarks that I'm using (I'm running some of them them in 7mm, 30 & 338 calibers). - And as well it surely points out that some handloader's have that "need for speed" syndrome. - It also makes me wonder if in that spoken of instance possibly if a carbon ring maybe had started to develop after some of that hot-rodding ensued ? and possibly that's the reason after it was "toned down" some it never came to shoot as accurate as when it did when he was pouring the steam to it. ?
Deleted old_dood
YMMV. I just broke in a new Shilen select match barrel using a moderate load of CFE. I'd say it was done in 10-15 shots. I was cleaning with Boretech Eliminator which usually shows blue on the patches rather easily. As a matter of fact, after about 100 rounds since then, I'm still not seeing any blue. I use CFE for fireforming (223ai) and Varget for my target loads. My next barrel will be from Shilen.
Well.......because "I" don't make barrels, I've always deferred to the recommendations from the people that do make them.
This is what Kreiger has to say about it.
https://kriegerbarrels.com/faq#breakin
This is what Kreiger has to say about it.
https://kriegerbarrels.com/faq#breakin
WyleWD
Silver $$ Contributor
WD
4xforfun
Gold $$ Contributor
^^^^This^^^^
I figure that there are TWO parts to break in.
Part one...fouling and ease of cleanup.....
I always do a shoot, clean, shoot for at least three shots. With the last dozen Kriegers and 2 Brux, that is all it took.....the bbls then simply cleaned up with just a few wet patches.....even after long strings. This ease of cleaning lasts untill the bbl starts to fire crack and collect copper...then the brushes and JB/Iosso come out for the rest of their service lives. Now, I did recently sent a bbl to my smith with 140 rounds to get scoped.....I had never used a brush or paste in this tube (other than the first 3 shot breakin period)....he found some carbon. He didn't say carbon ring...and he didn't think that it was in accuracy robbing amounts...but it was there. Now, it could well be that ALL of my tubes had some carbon in them at this stage, but I had never had them scoped at this stage of their lives.
Part two.....like ShootDots says...the BBL "speeds up" for the first 75 - 125 rounds. This is the part of BBL break in that nobody talks about...and it is a "thing"....it happens to every BBL, and if you find a load in 10 shots, it most likely will go out of tune...unless you have a LARGE tune window.
Just my .02,
Tod
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