Breaking in 6mm creedmoor.

[Tanner Garrett]

I just brought a 6mm Creedmoor with a impact action and foundation stock. I don’t reload yet, but brought 1000 rounds of Hornady match 108 gr. I broke in the barrel and shot several groups, most of which were below .5 Moa. The muzzle velocity started at 2911 and has sped up to 2965 after 160 rounds. My question is how many rounds does it generally take for the barrel to set in, and speed up or with factory Hornady match ammo will it speed past 3000 FPS?
Thanks

 

[Dthomas3523]

Depends on the barrel. Some of mine have stayed around 2980 or so. I’ve had others top out around 3120 with hornady 108 eldm.

After 165 rnds, I wouldn’t expect any further significant increase.

 

[Ripdog28]

After the money you dropped on that, spend $500 and get a reloading set up. $1200-1500 will get you a great set up.

 

[ShtrRdy]

What length barrel do you have on that?

 

[Ranger188]

I'm no expert but, with the half dozen or so barrels ( custom rifle cut, hand lapped )
I usually don't do any meaningful load testing till I have 100 rounds or so down the barrel
Just what I've found in my experience.

 

[Tanner Garrett]

What length barrel do you have on that?

26”

 

[sandwarrior]

I just brought a 6mm Creedmoor with a impact action and foundation stock. I don’t reload yet, but brought 1000 rounds of Hornady match 108 gr. I broke in the barrel and shot several groups, most of which were below .5 Moa. The muzzle velocity started at 2911 and has sped up to 2965 after 160 rounds. My question is how many rounds does it generally take for the barrel to set in, and speed up or with factory Hornady match ammo will it speed past 3000 FPS?
Thanks

When your barrel plateaus after initial rounds, it's broken in. As far as accuracy break in, it's a true thing but really pertaining to old things. We didn't have the machining capability back when. And, lapping of custom barrels has gotten a lot better...in large part due to better machining.

Before the hordes come and smite you down for breaking in a barrel, just understand it isn't going to make a 1" barrel a .5" barrel @ 100 yds. It's more for smoothing out that .2" to .1". You're knocking down minute machining marks that can make a difference. Most custom barrel makers lap the barrels so it isn't an issue there, and most custom gunsmiths lap the throat. All "break-in" is really doing is fire-lapping the throat. If you need it. You've seen a difference already in first rounds vs. a couple boxes later.

 

[Subwrx300]

When your barrel plateaus after initial rounds, it's broken in. As far as accuracy break in, it's a true thing but really pertaining to old things. We didn't have the machining capability back when. And, lapping of custom barrels has gotten a lot better...in large part due to better machining.

Before the hordes come and smite you down for breaking in a barrel, just understand it isn't going to make a 1" barrel a .5" barrel @ 100 yds. It's more for smoothing out that .2" to .1". You're knocking down minute machining marks that can make a difference. Most custom barrel makers lap the barrels so it isn't an issue there, and most custom gunsmiths lap the throat. All "break-in" is really doing is fire-lapping the throat. If you need it. You've seen a difference already in first rounds vs. a couple boxes later.

^^^^+1 to this ^^^^.

Any barrel by whomever will speed up slightly, tighten up slightly and foul less over the first 100 rounds or so. Clean it mildly before shooting first round, shoot one, two or three rounds then clean/decopper and then shoot it normally.

(edit: your past this point so justbleaving in for posterity) I use first 100 rounds to find rough sweet spots in SD and group size with 1 or 2 different bullets using .2gr charge increments, along with positional practice. After 100 rounds(ish), I fine tune seating depth and confirm dope at extended range. By 150, I've got a solid load, confirmed dope to distance, have consistent velocity, and barrel is ready for local matches. After 200-250, it is as good as it will be, I've learned the barrels "quirks" and I'll use for big matches that matter.

 

[ThePretzel]

After 100-150 rounds you won't see any velocity changes that aren't due to the barrel needing cleaning.

From this point forwards just leave the rifle be until you notice a significant change in barrel accuracy, POI, or muzzle velocity that isn't accounted for by environmental conditions (temperature, wind, barrel temp, etc.). When you see that, give the bore a cleaning and then go back to shooting.

 

[davere]

^^^^+1 to this ^^^^.

Any barrel by whomever will speed up slightly, tighten up slightly and foul less over the first 100 rounds or so. Clean it mildly before shooting first round, shoot one, two or three rounds then clean/decopper and then shoot it normally.

I'm only on my 2nd barrel (weak sauce, I know... LOL). This is exactly what I did with this one, except I shot 5 rounds up front (and chrono'ed each, just for giggles). The barrel sped up significantly in the first 3 rounds, and then stabilized to roughly where it is now after 140. I cleaned after 5, then again after 40. It didn't actually need it after 40, but I wanted to gauge how it was doing in terms of fouling. It was nothing notable that way - just normal fouling.

After 100-150 rounds you won't see any velocity changes that aren't due to the barrel needing cleaning.

From this point forwards just leave the rifle be until you notice a significant change in barrel accuracy, POI, or muzzle velocity that isn't accounted for by environmental conditions (temperature, wind, barrel temp, etc.). When you see that, give the bore a cleaning and then go back to shooting.

That hasn't quite been my experience. Somewhere around 1000 rounds on my first barrel (I'd have to go check notes), it slowed down about 65 fps, and has stayed there since (now at 2200). I had to back off a node, so I effectively lost about 85 fps. It's been cleaned to "bare metal" (well, close, anyway) 5 or 6 times since. No change. I'm told that some barrels just do that - they'll hum along and then slow down a bit at some stage. Then they'll hum along fine from there until they die. The barrel still holds 1/2 MOA, and is still useful for matches. My plan is to cut it down to 16.5" and use it for hunting w/ a can.

For reference, both are Bartlein, and are chambered in 6.5 Creedmoor.

 

[Dthomas3523]

I'm only on my 2nd barrel (weak sauce, I know... LOL). This is exactly what I did with this one, except I shot 5 rounds up front (and chrono'ed each, just for giggles). The barrel sped up significantly in the first 3 rounds, and then stabilized to roughly where it is now after 140. I cleaned after 5, then again after 40. It didn't actually need it after 40, but I wanted to gauge how it was doing in terms of fouling. It was nothing notable that way - just normal fouling.



That hasn't quite been my experience. Somewhere around 1000 rounds on my first barrel (I'd have to go check notes), it slowed down about 65 fps, and has stayed there since (now at 2200). I had to back off a node, so I effectively lost about 85 fps. It's been cleaned to "bare metal" (well, close, anyway) 5 or 6 times since. No change. I'm told that some barrels just do that - they'll hum along and then slow down a bit at some stage. Then they'll hum along fine from there until they die. The barrel still holds 1/2 MOA, and is still useful for matches. My plan is to cut it down to 16.5" and use it for hunting w/ a can.

For reference, both are Bartlein, and are chambered in 6.5 Creedmoor.

For me personally, once a barrel takes that first drop, it’s a training or non points club match barrel. It’s still useable, but I know another drop is going to come at some point (or just die) and would prefer it not be in a match I care more about.

I’m shooting 6creed though. So the life experience of barrel seems to be different. 6.5 seems to be able to hold on after that first velocity decrease and then kinda take steps towards dieing. 6’s seem to run good and then just die suddenly.