Barrel speed up after/during break-in

[Boatninja]

Just curious what kind of speed increases one might expect after/during break-in? What would be extreme?

 

[Steel head]

I got about 80 FPS on my recent 7 saum barrel.

 

[AIAW]

Just curious what kind of speed increases one might expect after/during break-in? What would be extreme?

Might not see any increase, might see a little, or a lot. Impossible to tell as barrels are all unique. My 28" Bartlein 300NM saw virtually nothing. Bartlein 27" .260 - about 45 fps at the ~200 round mark. It can be a difficult metric to measure if your load development overlaps the possible "break-in".

Extreme would be over 100 fps.

 

[King_beardsly]

I picked up about 70fps with my 6 creedmoor

 

[Joeydias3]

I have a criterion 6 creed remgae. With 107 smks it jumped 150 fps after it was broken in. Right around 100 rounds. Went from 2950 to 3100. Fastest barrel I’ve seen.

 

[dirthead1]

No way to know for sure, but I’ve seen 50-150 FPS increase between 80 and 125 rounds.

 

[blbennett1288]

I got an extra 20fps w/ my 6BR after 100 rounds

 

[FUNCTIONAL]

Average is about 40-80 but like mentioned ive seen as little as 20 and as much as 100.

Personally i bank on 60 fps.

 

[kgoltz]

I've typically gained 75-100 ft/sec. on a Proof Carbon after 150+ rounds, makes load work up early frustrating but after 150 rounds its been great!

 

[clark33]

My 6 Creedmoor saw 80fps increase around the 200 round mark. Went from avg 2940 to avg of 3020 with the hornady match ammo

 

[LoneWolf_052713]

Different barrels/cartridges with different characteristics...

243 win XCaliber 80-90fps
6 Creed in XCaliber Cryo Treated barrels I saw as much as 120fps when they finally settled down
XCaliber Cryo Treated 6.5x47 50-60fps
Hawk Hill 6.5x47 I saw it speed up and then settle back down maybe like 25-30fps

 

[Hawk in WY]

I wonder how much of this is lot to lot variation in powders or loaded ammunition.

Has anyone seen reduced velocity?

 

[LoneWolf_052713]

Most of it is due to lot to lot variation in barrel steel. Components is a 2nd factor, but I've crossed over to multiple barrels using the same lot of components numerous times.

Yes a current barrel spiked up then settled back down. once it flatlines I load dev and move on with life.

 

[FUNCTIONAL]

Agreed with LoneWolf on barrel steel variation, even within a same lot of steel it could finish different from barrel to barrel.

Also the reamer cut at the lands should contribute to the velocity gain. once it looses any type of burr and starts getting softer edges I'd expect it to help gain speed.

 

[Southpaw Shooter]

With my X-caliber 6mm Creedmoor barrel I seen a 70fps shift around 300 rounds. My Shilen 6BR picked up about 45fps at 200 rounds.

 

[jcomar1]

I need to chrono mine again and see if it's picked up any speed.

 

[JMcQ]

Bringing up a old thread to add some data. Firt shot 2418 with a 4 shot average of 2474
5th shot 2618 with a 4 shot average of 2618. Barrel is a Steel Proof 20in 6.5 Creedmoor. Factory Hornady 140 eld ammo for break in. I did take out the chronograph for the next 25 rounds but will next session to see what it settles at .

 

[celltech]

And maybe even more important....did the speedups cause any accuracy changes?