Reloading for a lever action and a semi automatic can be quite a handful at times in trying to get the case just right.  The action just doesn't have the mechanical advantage that a bolt action rifle has to push the case into the chamber.  Since you are not having any problems with factory rounds I would suggest for you to try a small base reloading die. 

http://www.midwayusa.com/viewproduct/?productnumber=843696

Also you might try turning the necks down after sizing them.

As far as sending it back to the importer/factory I doubt that it would do any good since they do not recommend for you to use reloaded ammo and it chambers factory rounds just fine.   

This defintely sounds like a sizing problem, it seems that the chamber in your rifle is tighter than your dies are sizing down to.  Please keep us posted as you figure out the solution, but it seems to me that you are on the right track now.  Good luck!

Had the same problem with 1 i had a few years back ,got to the stage i had to cycle every round thru just to be sure they would didnt matter wether they were reloads or factories there would always be a few that wouldnt ,loved that gun but i just didnt feel confident with it even though i shot a few sambar with it .But after a very dangerous near miss checking some ammo  i got rid of it,my mate had similar problems with his to.