Barrel speed up low rnd count

[Wizbang]

Just got a 7 prc prefit for my tikka. Put it all together, loaded up 150 rounds of 195 bergers and started shooting.
Starting average velo was 2555. After 67 rounds I picked up velo at an average of 2593.
Little insight,

All shot strings have not exceeded 5 rounds with about 45 sec to 1 min between shots.

I have cleaned after every 15 to 20 rounds

Environmental have not changed extremely (elevation, temp, humidity ect)

All components are of the same lot numbers and loaded at same time.

Has anyone had their barrel speed up with such a low round count? Typically all of my other barrels have been around 110-130 rounds before they picked up speed.

 

[wapitibob]

I shot my 7prc, N570 and 195's, over a Garmin chrono that a guy had at the range, 2990 avg for 4 shots. The barrel had roughly 100 shots on it. It has about 150 now, no idea of speed as I don't own a chrono but I haven't changed my drops.

 

[alexnelon]

Magnums speed up a lot faster. They’re usually stable after ~75-100 rounds.

 

[Wizbang]

I shot my 7prc, N570 and 195's, over a Garmin chrono that a guy had at the range, 2990 avg for 4 shots. The barrel had roughly 100 shots on it. It has about 150 now, no idea of speed as I don't own a chrono but I haven't changed my drops.

Guess I should have added that I shoot every shot over my athlon chrono.
This is just a starting charge of 62 gr Retumbo with cci 250’s and ADG brass.

 

[Wizbang]

Magnums speed up a lot faster. They’re usually stable after ~75-100 rounds.

Have you experienced this personally? Just asking because 4 of my other mag barrels that I’ve broke in the same way took over 100 Rnds, my 300 wby being the only one that was at 103.
On the plus side, this 7 prc barrel is a shooter. Makes me feel all tingly.

 

[Wizbang]

Went and shot the rest of my original 150 this am. I can confirm my barrel jumped in velo at 67 rounds as it is stable now. Blows my mind that it did this so quick.

Components
ADG brass
Cci 250
Retumbo @ 62 gr
195 Berger eol

Cleaned after spinning the barrel on with kroil

Cleaned every 15 Rnds after with bore tech eliminator then bore tech copper remover. Patched out with kroil and then 4-5 dry patches. Then cleaned chamber with rubbing alcohol.
This barrel seemed to clean up with minimal effort.