What the chamber reamer was used . . . hopefully something that equates to Match for some particular brand like Eley, RWS or Lapua.
What barrel was used?
My Remington 40XBR was chambered with an Eley Match Reamer and a Lilja barrel but testing of ammo is still required.
My CZ455 American will group five shots under one inch at 100 yards with Remington Eley Match but a lot of ammo has been funneled through it.
It has been pillar bedded, the firing pin reshaped and a YoDave trigger kit has the weight down to around one pound.
What was wrong with the factory barrel? Did a scoping show some serious faults?
The Federal Match appears to have been abandoned with the third group . . . it really is an oxymoron to call it "MATCH".
While the comment was made about your older ammo, it will still accomplish breaking it in and you are currently round 150 rounds. Better results should be seen after about 300 - 500.
Since you went to the expense of rebarreling are the results worth it. Further testing is required and will await your replies.