Can anyone help me find information on any aftermarket BOSS type systems and who can install them? I am not really interested in a the muzzle brake function but the fine tuning I find really neat (like what is now the Browning CR).

Check out www.brownells.com for the Que muzzle brake. It's both a brake AND barrel tuner. It was brought out as an aftermarket alternative to the Browning BOSS system. Shortly after ordering and receiving mine years ago, Browning sued and caused the Que to be taken from the market for a couple of years. The suit was settled and Que is once again available.

This system is meant to be installed by the home gunsmith, or you may have it installed by a gunsmith. Installation is simple - you measure the barrel's diameter as instructed a distance (1 3/4" I think) behind the muzzle, send this info in with your order and upon receipt, apply heat to the heat sensitive painted area until they change color. This heat shrinks the unit to the barrel. I used a paint stripper heat gun set on about 450 degrees heat to install mine. It has been there for years and probably a thousand rounds of 6.5x55 ammo with nary a bobble.