Your definitive answer is that, under federal law, YES, you may transfer a title I home made firearm in the same manner as any other title I firearm, including succession. Title II builds would be dealt with as any other NFA weapon.
What you may NOT do is manufacture with the intent to distribute without a license.
What does that mean? How do you prove, if accused of manufacturing and dealing without a license, that you had no such intent? Well, there is no finite timeframe that must pass between manufacture and transfer, nor any figure on the number of builds that would constitute it (sound familiar? Same as no "cut off" to the number of commercially produced weapons you may transfer without a license). So it really comes down to what is reasonable. Sold a home build you did years ago to a buddy? No problem. Sold a dozen "80" builds you made over the last month? Pretty easy to label that one with intent to distribute.
