Are these worth anything or are they best avoided? Are there any venders here who sell them? Thanks

I'd avoid them, unless you want to modify your barrel to aid in holding them on.

Think about the mechanics of what is going on there.  The brake is directing gasses back, to counteract the recoil forces.  In doing so, an equal force is applied on the brake, in relation to the barrel, pushing it forward.  In many cases, the brake ends up flying down range, being expelled by the gasses acting on it.

I had one setscrew brake and I had to dimple the barrel to keep it on.  

YMMV.

They will work loose even with locktite , the barrel will heat up &  release the locktite  "at least that's been my experience" , also I noticed very heavy dimples at the end of my match target barrel from where I  had tightened the set screws ...if you can, spend the money & get the barrel threaded , it'll be worth it

Just get the barrel threaded by Adco...

$65.00 and done in a few days

Look on the bright side. If you don’t shoot the bad guy, at least you’ll knock him out with your muzzle break. I had one launch almost fifty yards once at a range.

Muzzle B - R - A - K - E.

Brake, as in to slow down.

.223/5.56 does not have enough recoil to warrant the expense of a muzzle BRAKE.



Muzzle brake, to reduce recoil.  Nice to have on large calibers... especially .50BMG.

Flash suppressor, to reduce muzzle flash.

Compensator, to reduce muzzle climb.

Three different devices, for three different purposes.

They often become UFO's!  

Get one thats threaded or pinned on.  The pinned on type will be a little harder to find though.  Dont get the roll pin type, get the one that use the same pins as the front sight base.