You'll definitely need to re-zero after installing a threaded brake. If not due to harmonics, then due to the fact that the barrelled action needs to be removed from the stock to be chucked in the lathe. I also don't think it'd be wise to turn it in the lathe with the scope mounted.
You should be able to remove/reinstall a threaded brake with repeatable results. A clamp on brake would be more difficult to clamp back into the smae position with repeatability.
Worst case is that you may want to go back and tweak your load.
It's rare to hear about deteriorated accuracy from a properly installed brake. ...improperly installed is another story.
-- richard
+1
It is possible to install a break without taking the barrel and action apart, but I would not recomend
leaving the trigger , or the scope mounter to the action, (To much chance of screwing up eather one).
If a threaded break is fitted well and the shoulder is Square where it will make up clean, it should
index perfict every time unless you hammer it on, then it will progress each time.
It is however a good idea to check your zero each time you re install it if you plan on extreme
distance shooting.
The reason that indexing the same is so important is because a break discharges gas that may
have an an effect if it does not aim this gas discharge in the same direction each time.
There is a way to install a clamp on break so that it will index true and will line up with the
bore but the process is more expensive and with the break already costing more it is just not
worth the effort and money unless there is a specific requirement for one.
J E CUSTOM