I used to have alot of problems with buckling when using Patterson reels, especially with 120 film until I started clipping a tiny bit of the front corners off the film (at about 45 degrees) before loading. The film no longer seems to snag and so it doesn't buckle when you twist the reels to load it forward. Also, for 120, I found that the Samigon reels (which fit as perfect replacements for the Patterson ones) are much easier to load correctly as there are tabs at the film entry that help in the initial alignment.
Michael