I have been running a 6br on the encore platform for about 10 years. I have found it one of the easiest cases to load for. My barrel was made from a very inexpensive blank and it shoots extremely well. I get very good results from a 85 grain Sierra over Reloader 10x. Dont forget that the lapua brass takes the small rifle primer when you are getting your components together. You may also want to open up the flash holes a bit so your decapping pin wil be able to fit through. Sinclair Int. makes a tool for the job.
IMO you cant go wrong with an upper or rifle from Harrison.
Let us know how she shoots.