screech , I haven't given the standard JP brake a honest heads up compairison with any other brake so saying yes or no wouldbe miss leading.
BUT , the desgine says that the standard JP brake would be more effective than the Bennie Cooley as it has alot more surface area to catch and divert the gas.
I can say however that the Bennie cooley brake turned a 10lb 300RUM into a total ***** cat at the bench.
I have heard that the OPS inc. brake is just as effective maybe a little more than the Holland and Bennie Cooley. I know a guys that tested several brakes on a 10lb ish 300Ackley and he liked the OPS brake the best for recoil and noise , I thought it was **** loud