Although there is conflicting posts regarding this rifle from the OP, this isn't a reason to disparage the OP or for the OP to get super defensive about being called out on it. The knowledge base here is truly fantastic but only as useful as the info provided. Since the adage regarding computers applies to group discussions too, as the saying goes...Garbage in, Garbage out.
It is simply impossible to find a solution to such a complex problem with so many variables without enough reliable data.
1) Assuming a large ES from an optical chronograph from a brand new reloader as accurate is a giant assumption. OP has not answered the numerous posts about lighting or distance greater than 30' so we as a group have no idea if he is even using the chrono correctly. "Tested with a 9mm" is not reliable data. A 9mm powder charge will not send unburnt powder as far as a 300wm will so a 9mm will not show errors at the same distance a 300wm will either.
2) Problems with scope/mounting will certainly cause giant groups. Loose reticle, over extended turret, loose rail, lose screws, rings mounted too close to turret pinching erector. Goofy assumptions on what is needed for 1mile shots such as excessive rail angles, shims, coke cans, hot glue have all been seen (not necessarily in this particular situation). Relying or even paying a store employee to mount a scope is an obnoxious waste of money that shows the confidence level of OP with mechanical things as well as a lack of knowledge.A stranger cannot mount a scope properly without the shouters body present to position it properly for eye relief and comfortable shooting positi
3) Load development can be a a giant contributor. In previous posts in other threads, the OP stated he measured BTO in this rifle/load and set back from there. However, I have yet to see if the OP did more than assume brass length in a book was to his rifles chamber specs. It is imperative to check brass (no bullet needed) fits the chamber. If it is the slightest bit too long and the OP doesn't catch the slightmy harder bolt close with empty brass then he can be crimping the neck on the bullet causing high pressure and erratic velocity. The OP should most definitely check this when he restarts load development on any future rifles. Assumptions do not make for reliable reloading. Also using a beam scale is not a foolproof method if attention to detail of knowledge of scales is not involved.
3) Pressure signs. The OP hasn't provided pictures of brass to show blackened necks orflattened primers or other tell tale signs that will be very helpful in diagnosing the issue.
4) H1000 is extremely temp stable so time in chamber is clearly not the issue causing 200fps spread. However, the 200fps shouldn't be discounted in load development nor should the rifle be blamed for this with out proper info regardi g the use and setup of the chrono. Clearly a Magnetspeed or Lab Radar are better options and would eliminate this poor info is the OP has access to someone who has one and knows how to use it as errors in those systems also occur when not used properly.
5) Addition of muzzle break. Was this with factory threaded muzzle, gunsmith threaded with die or gunsmith threaded with a lathe without removing the barrel? We have no idea if the rifle was worked on by a Gunsmith or by a person at a gunstore who simply operates in that role. Clearly "gunsmithing" service like mounting a scope do not justify the title.
6) Parallax. As the OP is new to the technical side of reloading and unfamiliar with other common techniques such as bedding, improper parallax is not out of the question. As the OP is clearly a green shooter than many here, he may not be aware that If the scope is randomly mounted and the eye relief is not correct, we will reset his eye into the scope after each shot effectively aiming at a different spot on the target every time. Since there is so little information regarding the possible causes of the supposed 200fps spread shown by a possibly maybe accurate chronograph, it cannot be definitively ruled in as the cause if the large groups at this point.
Hopefully, the OP continues to use this rifle situation as a learning experience when he receives the rifle back from Bergara. Most of these questions and details will still need to be addressed regardless of what rifle the OP chooses to setup and reload for in the future. Good luck on your learning adventure.