New to building with lots of questions.

[montana]

If that happens then I agree you have to get creative. This is not about torqueing-up barrel nuts or muzzle devices but getting the barrel into the receiver in the first place. If it is a bit tight I use a Davidson barrel vise to clamp the barrel as close to the barrel extension as possible. Then put the Davidson in a vise so the barrel hangs vertically. Then tap the receiver on with a rubber mallet using a piece of wood that spreads the force over the back end of the receiver. With the barrel extension greased it slowly closes.

Other posters have advised heating the receiver in an oven while cooling the barrel in a freezer. Never tried it so cannot comment.

Klem, this does work. We do this with bearing races "cups" all the time.