Building my dads left hand midlength upper. the rear take down pin hole doesnt quite line up with the lower. Tried a few lowers all of them are the same. The hole is just ever so slightly back too far. Pin will go in but i have to force it and use a punch to push it out. Dont think it will cause a problem and will probably loosen up after some take downs. Does anybody think it will cause an issue? I can the hole in the rear lug is just a hair too far back but makes a tight fit. Upper and bolt are left hand parts from stag. Also how long should a midlength gas tube be? Mine seems a bit short. Heres a picture to show off the set up on my lower im building.




Barrel is a ballistic advantage 16" hanson with a silencerco flash hider with a Geissele 13" mk8 rail.

If it will allow you to pin it together (even if very tight) that is pretty darn close. Have you given any thought to a few light passes with an appropriately sized round file?

Upper seems to be out of spec. If it bugs you then send it back. If it doesn't bother you a whole lot than keep it. It wont affect function.

Since it's for your old man, I'd probably send the manufacturer an email.

From the photo it appears that you have both pins installed..... What am i missing??

I would try a different upper if possible.
If not, based on your description I would use it as is for a while and see if it loosens up.
If you file it you will remove some of the hard coat anodizing at the point where presumably the most pin wear will occur.

If it makes the setup tight and rattle free, just run it like it is.  I have a couple that started out tight.  They will break in.