6mm br help

[6mm06guy]

I just finished building a new 6mm br norma. But I'm running into some problems. It's a tight chamber, 1-8 twist with a 28" barrel.

I built this with the intent to shoot vermin and up to white tail I side 600 yards.
So here is the problem, all the load data you see online shows 28-31 grains of powder for the 105 bergers. I'm getting stiff bolt at 26 grains of varget.

 

[dustbag]

Do necks need to be turned? What velocity are you getting?

 

[K.E.C. Darkside]

What dustbag said.
Do you have the spec for the reamer.