Bartlein BB steel barrel, wearing one out...

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We get several calls a week regarding the new Bartlein BB steel and what realistic life expectancy may be. this thread serves to summarize our findings with a BB steel barrel and to share info publicly. This is not intended for people to ask what we stock, why dont we stock left hand gain twist barrels, what stuff costs, etc.

Our sample barrel is a 6mm 7.5 twist .237 bore M24, and was chambered as a BugNut barrel nut pre-fit for Defiance Deviant in 6XC. I started the barrel off with approx 500 rounds to validate accuracy and create a baseline. the barrel was then handed off to two different team shooters (who shoot more than me) to run in a PRS competition setting, so lots of 10 shot strings, etc. Both my team shooters who used this barrel said it was as good as anything they'd had, so everyone has been happy with the accuracy and performance. I received this barrel back in early April with 3220 rounds though it, and Im intending to shoot it till its done...

SO, when is the barrel "done"? a few things to cover regarding barrel life and how one determines when a barrel is shot out. First, accuracy expectations vary from shooter to shooter, as do barrel availability and resources to get replacement chambered barrels. For me and my team guys, we usually run a 6XC barrel for approx 2000-2500 rounds. A barrel is rarely pulled because it is no longer competitive, but because its near the end of its life and the season is over- or perhaps a shooter has a 30-40 day break between matches and its a good time to start with a fresh barrel. Some guys will pull barrels when they start shooting 3/4 or even 1MOA, some guys pull barrels at 1000-1200 rounds and only use the best part of the barrels life. With that being said, here's the standards that Ive created for this BB steel barrel so it can be evaluated by a "pass or fail" test to determine when it will be pulled from service. Again, this has nothing to do with scheduling, convenience, etc. This barrel is on a back up rifle and Im gonna run it until it fails the following criteria:
  • barrel must be able to consistently shoot 1/2MOA or smaller at 400 yards. I can shoot 400Y at the house so this is convenient for me. Evaluations will be done in good conditions
  • barrel must be able to shoot to the 1/2MOA standard for a 100 round interval without cleaning. If the barrel cannot shoot through a one day match without needing cleaning then it will be pulled from service
  • barrel must maintain a safe pressure state over the 100 round interval, meaning it cant get pressure spikes as the barrel starts to get more heavily fouled
note that there is NO provision here for velocity. I don't watch it for load development or monitor it throughout a barrels life so it wont be considered as long as the accuracy is acceptable. I rarely shoot over a chronograph, I just follow the accuracy regardless of ES/SD. Much of the data currently available for these BB steel barrels comes from ammunition manufacturers and deals with velocity and pressure . I dont know if they are pulling test barrels because of accuracy loss or not.
 
I started by shooting some 105 Hybrid and 115 DTAC loads I am running through my current match rifle. Moved on to load development with the 110 Sierra and 105 Scenar. The 110 has been a mediocre at best bullet for me, and I had a little less than a 500 count on the shelf. I figured if I could get something useable with the 110SMK then I could do barricade practice and burn through what I had left. The 105 Lapua Scenar has been a better bullet, but has not shot as well as some others I use so I have some extra of these as well. With components harder to come by I wanted to "utilize" extra components for this purpose. I did load development with these two bullets, and when Im out I'll see what kind of results I can get with 105 hybrids and 115 DTACS. After shooting these 100Y groups I shot a bit at 400Y to create my baseline. The 110SMK load was shooting approx 1.75" at 400Y and the 105Scenar load shot 1.25-1.5" at 400Y. Since I'll be happy to be rid of the 110 sierras, I started loading and practicing with this bullet.

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as of today 6/1/21 I have 3520 rounds through this barrel. I was about 80-90 rounds in since cleaning and shot some groups on steel at 400y. Im measuring groups on steel in increments of .100" since it can be tough to resolve exact point of impact. todays (5) three shot groups with 110 Sierra averaged 2.3". barrel will be cleaned and I'll head back out with a clean barrel (for comparison) and both the 110SMK and 105 Scenar loads to re-evaluate. Some days you just shoot better than others, I want to see if the 110 load will pass or continue to exceed 2" @400Y
 
I'm curious as to why you aren't tracking speed? That's one of the things that most of the PRS shooters I know use as a metric for barrel replacement. It seems most of them run a barrel until it starts to dump significant velocity over the course of 100rnds. Accuracy is usually still very acceptable at that point, but it causes issues with dope at longer ranges.
Excellent info none the less.
 
Watching. I just got my 6cm 400MODBB barrel from you about 6 weeks ago. Waiting on my action to get out of 10 day jail to start shooting it.
 
I am also curious to why you are not tracking speed? I have very limited experience but I have toasted two barrels. Both were 6.5 caliber, one chambered for 6.5x55 Swede and one was a 6.5x47 Lapua.
I bought the 6.5x55 used and have no idea on round count. Over the course of 987 rounds, shooting 139 grain Lapua Scenar it lost about 280 fps using the same load from day one. It still shot great. I shot the tightest groups I have ever done with that rifle. But the speed went down the drain as the barrel ware out. Just from looking down the bore it looked like a smoothbore for the first 5-6".
The 6.5x47 Lapua was a Shilen Select Match barrel. After about 2200 rounds of Norma GT 130 grain doing 2650 fps (not a hot load), it had lost about 200 fps. I switched powders which brought it back up to speed and accuracy was never an issue. That rifle still serves well as a hunting rifle, but it was finished as a competition rifle for me.
So I would think that the 400MODBB barrel will probably shoot quite well for a long time, but without tracking speed and only accuracy, I am not sure that we get the full picture.

Oh, and I very much want a 400MODBB barrel for my Sako TRG once it needs replacement. But I went back to the fuddtastic 308 winchester. So it wount need replacing any time soon.
 
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First I should say that my approach to load development has been viewed by some as unorthodox. I dont do much seating depth adjustments, rarely shoot over a chronograph, and basically never fiddle with my load to keep it in tune once the load is established.
I dont track speed for a few reasons, and some of those reasons stem from my available time and my availability to barrels and chambering resources. meaning I can put on another barrel at almost any time

Everything we do during reloading is to achieve accuracy and consistency. if groups are small at 600 and 1000Y, then your load is good. if I have an ES of 20 and Im shooting 3-4" at 1K then Im not messing with the load. Ive seen guys practically pull their hair out trying to get better numbers from their chronograph even while shooting a very accurate load. I dont have the time or the desire to be constantly fiddling with my load or shooting 200-300 rounds during load development. In my shop we call this "paralysis of the analysis". It all comes down to how close together your impacts are. I will spend considerable amount of time trying to keep chamber runout down and keep throats perfectly straight; dial indicators can measure this success. My shooting and reloading success is measured in group size not chronograph reports

If the barrel is slowing down this is indeed a sign that its near its end. Its a sign for me to watch a little closer for unexpected flyers, etc. But if my 1000Y dope goes from 7Mils to 7.3Mils this summer I couldnt be bothered. Could be velocity, sunlight, where I have my shoulder on the butt pad, or how hard Im pre-loading the bipod, etc. as long as its still shooting good the barrel stays in service
I work around rifles daily, I have lots of numbers in my head. I shoot many rifles and struggle (some times) keeping up with the intricacies of each rifle. G&M codes, orders, material, margins, & lead times I must focus on. when work is over and I want to shoot, I dont want to fiddle with more numbers, I just want to relax and shoot. I dont go to the doctor and I dont do wellness checks on my barrel. when Im dead my wife will know it and when my barrel is dead I'll know it
 
The test barrels I've gotten back....accuracy wise would still shoot but being as they are mostly being used for pressure and velocity testing along with accuracy.....

They don't want to see a pressure correction of more than 2k psi and I forget the velocity swing number. When they see those two numbers tie together they know the barrel is on it's last legs and for loading box ammo....and too meet the pressure and velocity spec's for that box ammo....they no longer can use the barrel for testing regardless of how good the accuracy is. So the 6.5CM barrel I got back like two weeks ago had a pressure swing of 1800psi and I want to say a velocity drop of 80fps. So it got pulled. The barrel had over 3500 rounds and standard material test barrels are only making it to about 1700 rounds. They can milk them to about 1900 but usually at 1700 round count they get pulled when they see the velocity and pressure number swing.

A good example but out of most peoples realm is 50BMG....if the barrel (standard material) is being used strictly for accuracy testing (at 50bmg specs) they tell me the barrels will go up to 5k rounds but if the barrel is being used for both pressure and velocity along with accuracy....the barrel usually doesn't make it past 3k rounds because they see the swing in the pressure and velocity numbers and they cannot rely on the barrel for making box/spec ammo.

Thanks for the post Greg and the update. Hadn't heard anything in a while about that stick.

Later, Frank
Bartlein Barrels
 
Sorry, I didn't mean to kick the can of worms.
My curiosity had nothing to do with load development, ES or SD. Just simple average velocity, and how it relates to group placement on the target.
My experience has been that as a barrel nears the end of its life, speed will begin to drop 10-20 fps per 100rnds in a match. That's pretty manageable, but shortly after that point it will rapidly drop 100fps or more.
A 100fps drop over the course of a 300rnd-2 day match is enough to turn a top 10 into a mid pack waste of time and money.
I was simply saying that by monitoring my average speed I can pull the barrel at the 10-20fps mark. I know a lot of other PRS shooters who do the same, or they add a few tenths of powder and only shoot 1 day matches for the remaining life.
Again, just my experience as to what constitutes a "dead" barrel.
I'll leave it at that and look forward to your results.
 
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First of all, let me say this: I don't compete at a high level. When I'm shooting at a match I'm on vacation- if its raining or otherwise shitty, Im going home. So if I don't come in the top 10 that's not a loss or disappointment for me.

-I agree that watching velocity can be a good indicator of a barrels condition
-I wound not go to a 2-day match with a barrel that is questionable or near the end of its life
-I would prefer to shoot more at further distances for the purpose of this evaluation, but I have a wife and kids and work 70-80 hours a week
-if the sun is shining on me, I get a mid-pack finish, and I had a big time shooting with my buddies, thats a good day

the discussion to when a barrel should be pulled form service is entirely valid for this thread, and welcomed. we all have our own standards and criteria to make the decision
 
The 110 sierra load will no longer meet the accuracy requirements, so I’m burning them for barricade practice. I’ve switched to the 105 Scenar load to monitor accuracy. Cleaned all my mufflers today and re-zeroed. 5 shots at 100y with the scenar is looking good. Shot (4) three shot groups at 400Y and the average was 1.7”
 

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I started by shooting some 105 Hybrid and 115 DTAC loads I am running through my current match rifle. Moved on to load development with the 110 Sierra and 105 Scenar. The 110 has been a mediocre at best bullet for me, and I had a little less than a 500 count on the shelf. I figured if I could get something useable with the 110SMK then I could do barricade practice and burn through what I had left. The 105 Lapua Scenar has been a better bullet, but has not shot as well as some others I use so I have some extra of these as well. With components harder to come by I wanted to "utilize" extra components for this purpose. I did load development with these two bullets, and when Im out I'll see what kind of results I can get with 105 hybrids and 115 DTACS. After shooting these 100Y groups I shot a bit at 400Y to create my baseline. The 110SMK load was shooting approx 1.75" at 400Y and the 105Scenar load shot 1.25-1.5" at 400Y. Since I'll be happy to be rid of the 110 sierras, I started loading and practicing with this bullet.

View attachment 7638372

3610 as of last night
Outstanding post.
 
A couple of the guys here where down at the Punisher this past weekend. One of the top PRS shooters has a BB material (actually has several) but his first one in 6BRA now has 5700 rounds on it. He officially pulled it 4000 rounds because he thought it was going to go and didn't want it to go at a big match.

So he is using it for practice and will pull it when it truly dies but at this point in time at 5700 rounds he says no velocity loss and no accuracy lost. He's wondering if it will go 8k rounds. He's gonna keep us posted.

I think this is above and beyond the norm but still positive none the less.

Later, Frank
 
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A couple of the guys here where down at the Punisher this past weekend. One of the top PRS shooters has a BB material (actually has several) but his first one in 6BRA now has 5700 rounds on it. He officially pulled it 4000 rounds because he thought it was going to go and didn't want it to go at a big match.

So he is using it for practice and will put it when it truly dies but at this point in time at 5700 rounds he says no velocity loss and no accuracy lost. He's wondering if it will go 8k rounds. He's gonna keep us posted.

I think this is above and beyond the norm but still positive none the less.

Later, Frank
Could you have him share with us his cleaning regimen? Just curious what it looks like since everyone's got their own kind of snake oil for cleaning and clearly he's doing something right.
 
Yes they are a thing. Have done bunches of them.

I have two myself. One for my Impact action and another on my Sig Cross rifle. Both green in color.

How well do the carbon colors turn out? I’ve been kicking around getting an 18” or 20” 6.5 PRC for my hunting rifle once the current proof barrel dies and was wondering if the black, green or red would look best.
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The last proof died at 1100 rounds so I’m hoping the BB400 will at least get me to 2500 rounds to make it worth the switch.
 
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The green one is on my Impact action. The next picture is of a black and a red/brown one. Those two in the one picture got polished. In the sunlight or picture flash the color really stands out better.
 

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How well do the carbon colors turn out? I’ve been kicking around getting an 18” or 20” 6.5 PRC for my hunting rifle once the current proof barrel dies and was wondering if the black, green or red would look best. View attachment 7658556

The last proof died at 1100 rounds so I’m hoping the BB400 will at least get me to 2500 rounds to make it worth the switch.
I’d go red. The green will be brighter than the OD green on your stock.
Mine:

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I have a 24” 6.5CM BB steel barrel with 600 rounds thru it. I measured throat erosion at 0, 200, and now 600 rounds. I’m using Berger 140 Hybrids and Staball at 2700-2750 FPS. I used the same bullet to measure using the slit case method. After 200 rounds the throat “moved” .010” and kinda worried me. But now 400 rounds later it hasn’t moved again. I think initially the throat was tight (diameter wise) and wore in by 200 rounds. My load is fairly mild so I attribute the lack of measurable wear partially to that but mostly to the new steel. This one might last a long time.
 
I have a 24” 6.5CM BB steel barrel with 600 rounds thru it. I measured throat erosion at 0, 200, and now 600 rounds. I’m using Berger 140 Hybrids and Staball at 2700-2750 FPS. I used the same bullet to measure using the slit case method. After 200 rounds the throat “moved” .010” and kinda worried me. But now 400 rounds later it hasn’t moved again. I think initially the throat was tight (diameter wise) and wore in by 200 rounds. My load is fairly mild so I attribute the lack of measurable wear partially to that but mostly to the new steel. This one might last a long time.

Glad you are using the same bullet/same measuring method. Bullets will vary from lot to lot. I've seen bullets vary an easy .0005" on diameter even from the same maker.

Also what the reamer cut the throats freebore diameter is another variable. First thing that goes on a reamer is the throat as it's always cutting regardless if you used a roughing reamer etc..and as it goes will start to cut undersize.
 
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A couple of the guys here where down at the Punisher this past weekend. One of the top PRS shooters has a BB material (actually has several) but his first one in 6BRA now has 5700 rounds on it. He officially pulled it 4000 rounds because he thought it was going to go and didn't want it to go at a big match.

So he is using it for practice and will pull it when it truly dies but at this point in time at 5700 rounds he says no velocity loss and no accuracy lost. He's wondering if it will go 8k rounds. He's gonna keep us posted.

I think this is above and beyond the norm but still positive none the less.

Later, Frank
@Frank Green could i get a 29" 224 barrel in BB? I have a 6BR BB and a std 22 dasher spinning now. Could make the 22 Dasher even more fun if I can go 3-3.5k rds on it...
 
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