This math ain’t math’n
- Thread starter Frank Green
- Start date
What math?
The powder to velocity math I would wager.
What kind of ES do you have? The math does seem a little out of sorts but I'm not familiar with the Dasher like I am the CM.
The old barrel was always slower and needed more powder. My Fiancées 6 Dasher is the exact same as mine, chamber, bullets and powder used. Only difference was hers is regular Bartlein stainless and hers was always more efficient than mine.
My old 6 Dasher barrel needed 31.8 of IMR4166 to achieve 2805 FPS with 109 bergers.
Fiancées 6 Dasher would run 30.7 of IMR4166 for the 2805 FPS
This new barrel seems to be in line with how fast her barrel is. So gonna assume the old barrel in general was just slower and need more of a slap to get rounds out of the barrel.
My old 6 Dasher barrel needed 31.8 of IMR4166 to achieve 2805 FPS with 109 bergers.
Fiancées 6 Dasher would run 30.7 of IMR4166 for the 2805 FPS
This new barrel seems to be in line with how fast her barrel is. So gonna assume the old barrel in general was just slower and need more of a slap to get rounds out of the barrel.
Todays ES was 7 FPS with a 7 round string. Average of 2862 FPS. This is with the new barrel.
Oh ok. I thought you might have some real ES numbers since you seem to shoot a lot and with that load. Your ES is still probably good. Even still, ES is probably not why the numbers look a little funny. Hard to belive you didn't get more rounds out of that modBB barrel. That's not consistent with every other one I've seen numbers on but there's a lot of factors to that so who knows
Your round count and that barrel being shot out. That’s pretty normal Numbers in my opinion.
Figured the Mod400XYZTUV barrel would last much more then that.
Well, that was the round count so I’m not sure what to tell you as I keep logs of all of my barrels round counts. Got the barrel directly from Bartlein too as a MODBB barrel.
Considering it was a lot slower barrel than my fiancées dasher’s barrel it could have just been a barrel that just gave out earlier than most.
Not gonna let one sample size give me a bad taste for the barrel material.
I’ve seen regular dasher barrels that didn’t last long compared to others give out around 1,100 and they were run at moderate speeds such as 2800-ish. So if this barrel was just a sample that gave out early for the material it’s still good in my opinion since it lasted longer than regular stainless that gives out early. We shall see how this new barrel performs now over time now.
I just switched over to 15.5 after running out of 4166. But I’m now over 300 rounds with this barrel and 15.5 and love it so far.
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Yeah I'd be interested to know how the next one does for you for sure. I thought dashers were supposed to be easier on barrel life than cm but as I said, there's a lot of factors involved in the number of good shots you get out of any barrel.
My first dasher barrel is a MODBB barrel and I'm pretty sure she's done now at just shy of 2500. It spent most of its life shooting 112 match burners with varget at 2840FPS. Then the last 1/4 or so shooting 109 hybrids at 2850. The barrel is 23.5" long and used for PRS competitions. Last time out speeds had dropped about 60-70FPS. I did a very aggressive cleaning and the bore still looks rough and not completely clean. I'm going to pull it and start with a fresh tube. Just throwing this out there for another data point. It's my first dasher and first MODBB material barrel, so I haven't really drawn any conclusions yet. But Bartlein is definitely my favorite barrel so far.
That's consistent with what others I've seen are getting. Thank you for posting the info.
My 400ModBB 6.5 Creedmoor died at about 5000, factory ammo Berger 144 mostly, PRS matches, 2800-2810 fps, M24 contour, 26", 1-8tw, built by Bugholes.
Current barrel on my Dasher is still doing well. At 1500 rounds after the PRS finale and no significant slow down yet. This barrel has seen only RL 15.5 for powder and 109s at ≈ 2860 fps.
Important to note my previous barrel that died early had a drop off of 50 FPS at around 500-600 rounds and died around 1840.
Important to note my previous barrel that died early had a drop off of 50 FPS at around 500-600 rounds and died around 1840.
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6 Dasher still purring at 2150 rounds
Is it just as accurate?
Have you noticed anything different like how it cleans or how much have the lands moved?
Still shooting a 3/8 group consistently and cleans the same. I recently, at 1800 rounds, checked the lands/jam and it moved about .060”.
Still hammering at 2400 rounds. However pulling it and putting a newer barrel on for 2 day matches. I will still be using it for local matches. Just don’t want to risk it at 2 day pro matches.
Thata awesome. My 6cm is still hammering along with 1000 on it now.
How fast are you running your dasher?
2860 with 109 bergers, RL15.5 and Alpha brass in a 26” barrel. Per GRT that’s about 55k PSI. So not pushing it hard by any means.
What did break-in look like for you, and has it held consistent MV up to now or are you seeing it tail off a bit?
MVs are consistent and my groups before last Saturdays match was 3/8” and I checked zero after and it was the same. I started this barrel at 31.7 of RL15.5 and I’m now around 32.2. Extremely happy with performance. The fire cracking with this steel seems to almost stabilize at some point. It looks no different when it was at 1200 rounds. Just an observation. I’m going to look at sending my first 400modbb barrel back to Bartlein to maybe help see what went wrong with it because that barrel and this barrel act completely differently. I’ll need to check my loading notes, but my first barrel needed 34+ grains of 15.5 to get around 2860 FPS after I switch from 4166 IMR at around 1700 rounds.
Ok, that's basically exactly what mine is doing so that's great. Is yours a modbb1 or modbb2?
not sure what you mean by modbb1 and 2.
My first barrel was an early modbb barrel that I got off their left over sheet from the site (late 2021). This current barrel I got from buffalo tactical around early winter of 2022. Same for the barrel I just put on the rifle.
I gotcha. The serial numbers on the ModBB have a digit after then indicating when they were made. I can't remember if it's lots of steel or what exactly it means and I'm on site so I can't look at any of mine right now but there's some single digit indication that differentiate the modbb barrel. Of course I have no idea if that matters and I very much doubt it does, I was just curious and comparing to the ones I have.
Gotcha, thanks. Do you recall how many rounds it took to break in? And what’s your metric for determining a barrel is match-ready? I ask because I have one showing up soon, and a match two weeks from now. If it takes 300 rds to break in, I’ll probably run a different barrel for the match.
Highly recommend sending a Bart barrel back to them if you have questions, I’m working through an issue with them right now (that was not caused by Bartlein) and they’ve been going way out of their way to help me out. 12/10 service
Would you not think that break in is more related to the quality of machining of the throat more than the steel. And throat quality goes to the reamer used and the smith that used it, no?
It’s not, but thank you. A side note: just because they’re break-in rounds doesn’t I’m not training.
I have yet to see anyone definitively assert what makes break-in go slow, fast, well, or poorly; we don’t really even have a definition, although most of us seem to agree that it’s when MV of a given load is consistent over some number of shots. But that’s why I asked what @jthor used as their definition.
200 ish probably. Honestly that barrels first use was at the 2 day king of coal canyon PRS match last year and I placed 5th. The previous barrel I discovered died on the sight in day of the match and luckily I brought an extra barrel. From when I Chronographed it at the sight in line after 5 shots to the end of the match it sped up 20 FPS. 3000 fps to start and 3020 at the end of the match.
Well, May want to ask @Frank Green. I believe his view is “break in” relates to smoothing the throat and if you’re not getting copper then it’s done.
I rather view this as separate from a barrel speeding up in the first 100-200 rounds.
Cheers.
for future reference for people reading these posts, I've not tried the new BB barrels unfortunately, too many stainless 6 creed barrels to burn through still, but dealing with the people at bartlein all 3 times I've done it was a pleasure. all three times were to put in orders, never had a problem out of a Barty blank. everyone I spoke with on the phone was always so nice, plus getting to read bartlein employees and owner opinions on here is great.
it's a sample size of three so it's not definitive but I think they are a little cautious on their wait times, definitely take the plunge and place a custom order and let them advise you on what to get because seems like all the people up there are pros at the shooting/loading stuff.
gain twist are underrated.
eta I just meant I'm a nobody with no real money. if they're so great to me I'd bet a dollar they'll be great to you.
it's a sample size of three so it's not definitive but I think they are a little cautious on their wait times, definitely take the plunge and place a custom order and let them advise you on what to get because seems like all the people up there are pros at the shooting/loading stuff.
gain twist are underrated.
eta I just meant I'm a nobody with no real money. if they're so great to me I'd bet a dollar they'll be great to you.
