I own and operate Alaska Silencer where I sell silencers and firearms. Lots of customers ask about threaded barrels and muzzle breaks, etc. First, I cannot determine whether the proper spelling is "brake" or "break".
My friends who work as Hunting Guides often complain of muzzle breaks and the extra noise associated with those items. Several of my friends have serious hearing loss in one ear from being close to too many clients with high powered rifles fitted with muzzle breaks.
Personally, I do not see the difference between loud and very loud, muzzle break or not. Hearing damage, the noise, and the consequences of hearing loss are the same. Proper safety is always expected. That includes hearing protection and eye protection. When wearing correct hearing protection, the muzzle break is of less consequence in terms of hearing damage.
The larger problem might be to consider why the muzzle break is needed. We known that recoil is an accuracy killer. Muzzle breaks certainly help reduce recoil thus improving potential accuracy. 6.5 Creedmoor should not need a muzzle break as it is a relatively soft low recoil round, even in an ultralight rifle like my Kimber Adirondack. Conversely, my Kimber Montana 30.06 great benefitted from the muzzle break.
If your barrel is not threaded then be very careful who you hire to thread that barrel. It is good to have the muzzle break or silencer at the time of threading to be sure it fits exactly as you expect. The consequences of even minor thread errors can be very dangerous.
