Just fitted the first large "Painkiller" and took some pics for the members to see. This rifle is SS7mm's 7mm AM. The 5 port Painkiller(PK) is really to large for this size of a rifle and the gas volume produced by this round but while its overkill, it works very well and thats all I will say about the performance because it will mean much more to have ss7mm do a non biased report to the members without my opinion muddying the waters.
In the back ground is my Raptor 300 AX with the medium sized 3 port PK brake with muzzle jump ports on top. In the foreground is the large 5 port PK brake. Again, this brake is designed specifically for my Xtreme Heavy Sporter rifles that weigh from 15 to 19 lbs and are generally chambered in my 338 AM and 375 AM. That said, they will work fine for any magnum chambering with a muzzle diameter of at least 0.850" and smaller then 1" in diameter. It can be used with larger muzzle diameters but they will be slightly larger then the width of the PK brake which is roughly 1".
Again, the large PK 5 port brake is specifically designed around the gas volume of the 338 AM or 375 AM or any other chambering based on the 408 CT case.
The PK brakes are engraved as seen above. In the case of this rifle, to keep the look as clean as possible, I indexed the brake so the engraving was on the bottom surface.
Just for size reference, thats a 3/4" Holland QD brake sitting on the 5 port PK brake. The muzzle is set up so its interchangable between the two so we should get some good comparision between the two from ss7mm.
Obviously this brake is not a small brake. Its designed for one purpose, controling recoil. As a result, its loud, but not noticably louder then a standard partition style brake design. How it performs, well we will hear soon.