BCM Upper and BPM Barrel Assembly Issue

[aviumvenator]

I have a new BCM blem upper and a barrel from a BPM rifle that I am trying to put together. I put the barrel in the freezer and the upper in the oven at 225. The barrel will not start in the upper. I think I gained about .002 on the heated upper and less than .001 reduction on the extension. The upper appears to be out of round. Is there a fairly simple fix for this or should I just buy another upper? I have an old lapping tool but it will not fit in the BCM upper.

Measurements:
Room temp barrel extension = .998
Room temp upper measurements:
3-9 o’clock = .999
6-12 o’clock = .996

 

[6.5SH]

Vise, torch and speed, don't hesitate pushing it on.



I do draw an index line on the barrel extension from the index pin to the end of the extension with a sharpie.

 

[aviumvenator]

Vise, torch and speed, don't hesitate pushing it on.



I do draw an index line on the barrel extension from the index pin to the end of the extension with a sharpie.

Thank you! That method worked like a charm. Way better that the oven and freezer.