I'll second the PK brake!! Even if the thread's a year old
I shot 50 rounds through my 9.5 lb 300 WSM pushing 180's at 3100'/sec one afternoon. It's actually pleasant to shoot (so long as you got good hearing protection in) and kicks less than my 8.5 lb 25-06 shooting 100 gr factory ammo at 3200'/sec. I was truly amazed. It was so enjoyable to shoot that I bought some fancy, expensive, in the ear, wear all day hearing protection so I could use the rifle for all
styles of rifle hunting............noise is the only downside to a brake like this.