New barrel speed increase

[magedon44]

Just had a 28 nosler built with Brux 26 inch 1:8.5 twist . The first three rounds out of the gun with 85 gr re33 and 195 Berger shot .5 at 3000 fps average with Es of 6 . Now on round 63 of the gun that same load opened up to one inch and is around 3070 with ES of 35. This is my first custom and never experienced this , is this normal ? If so when will it stabilize ? Thanks

 

[TH]

What tempatures did you shoot at? I do not have any experience with r33. But I know r 22 is extremely temperature sensitive

 

[magedon44]

What tempatures did you shoot at? I do not have any experience with r33. But I know r 22 is extremely temperature sensitive

Both days mid 60s

 

[Craveman85]

Barrel break in/wear? Same jug of powder? When I used to use rl15 for everything I noticed one pound I opened up gave me a different point of impact and pressure signs. Now I buy 5 containers and mix them. I'm betting it's broken in now and you just need to fiddle with the seating depth or adjust a few tenths to the powder charge.

 

[dok7mm]

Most barrels will break in with 50-75 shots and speed will increase nominally at this stage. It is fairly common to have to tweak your charge weight to find your way back to the previous accuracy node. You didn't state if you started with new brass or how many times your brass has been fired & how you resized it or your die set-up. Also, your CBTO length and jump to lands would be helpful. Have you performed a seating depth test ? The more info you share, the more helpful the responses will be. Three shots will not usually tell you much, as chrono or human error can really mess with your data. That being said, new brass can often shoot tiny groups because of consistent neck tension. Good luck with your new rifle.