Upper receiver modifications to fit

Ok,
I have been slowly working on my .308 build (Ironridge lower), I finally got my lower parts kit in the mail and I went to pin my upper and the holes for the takedown pin channel of the upper couldnt get low enough. The tabs are not hitting and the upper is fully seated.

The upper is a stripped POF (older gen) with chrome lining, I got it cheap a long time ago and I think i now know why.

My question is this, do you guys think I can/should get the hole in the upper elongated down to allow the pins to fit? Since it is fully seated, I feel like it will fit snug and not matter that the holes are not circle.
I will try to get pics, but should i worry about the tabs breaking if there is less material around the hole?

Anybody know who might be able to do this? I was thinking of asking ADCO?

lousy pic

File it.

I was thinking of taking it to my drill press, but filing sounds a lot better. I need to dig around for a round file

Chainsaw File.

Use a sharpie to blacken what shows thru the lower.

Ive got one pin done, turns out the hole was not only slightly out of line, but wasnt even big enough to begin with.
how much material should I have around the hole? It is pretty thin, if the back of the receiver is touching should I even worry about them breaking?

File it and take it slow, it will not break.

Get a small round file and do the clearing very slow, file and peep.

well it’s on, nice and snug.
Now i have a question for those of you with .308 receiver sets.
My upper receiver inner diameter is larger than the buffer tube threads, I am worried that once I thread the buffer tube in, the step will be a problem. Or is this normal?

Did you file the said hole or drill?

filed

Can we conclude that no upper and lower are exactly drop in?

There is always the need most of the time to adjust the holes of the said rear takedown holes of the upper receivers.

IS this that common for .308s?
I have never had to modify any of my 10 5.56 uppers