You need to find out why those rounds don't fit in the chamber. If the bullet is seated crooked, or bulges the case, the U die won't help. If you have bad brass, that has been loaded hot, and fired in an oversize chamber, it won't help. The U die will fix glocked brass better than the Dillon die, if that is your problem.
got the u die- it is made by Lee- to EGW standards- lets see how it works.