Anyone familiar with Excel chimney pipe?

[Aquaelvis]

I’m installing my stove today and there are small holes drilled where the two pieces of chimney pipe meet and get screwed together. No matter what I try I can’t get any of my pipe to sit down far enough to use those screw holes.
Is that common?
Should I just set them with the self tapping screws they provided? (even if I’m not hitting their hole)
I’m using Excel pipe.

 

[Aquaelvis]

That’s as far as I can get these to go

 

[Aquaelvis]

Looking inside the outer pipe you can see there isn’t much room to go down. Maybe 1/4 inch.
The inside pipe that has the hole you can see is deeper… no way these can line up.