Well, this winter I sent my Kimber 325 out and had it magnaported. NOT muzzled braked. My goal was to tame the muzzle flip. Life has been way too busy but I finally got out to run a few rounds through it to see what difference it made.
Murphy has described the recoil etc. on the light Kimber 325 as "torquey". I agree with him. You have to hang on to that sucker but the felt recoil at the shoulder is not has bad as my old wood/blue Ruger 06. Anyway, I am happy to say the magnaport does what it's supposed to do. I shot it six times off the bench and the muzzle flip and "torqueyness" is gone. I mean TOTALLY gone. It just snaps straight back into the shoulder. I don't feel that I have to "hang on" to the rifle any more to keep it from jumping and "twisting". I can't say for sure if it has any more felt recoil at the shoulder or not. Shooting six rounds gave me no shoulder pain or discomfort and I was just wearing a t-shirt. Someone around here thought that if the muzzle was not jumping that the force would be transferred back into the shoulder. I can't say for sure. To me the recoil is fine for a 7lb 8mm short mag.
As far as noise goes, again, I can't say for sure if it's any louder. My friend I was shooting next too didn't say anything about it. It sure wasn't any louder than the 338 RUM he was shooting!
Bottom line is the mag-na-port tamed the torqeuy muzzle flip of the Kimber with no discernable increase in felt recoil or noise as far as I can tell.
I only shot it six time because I didn't want to shoot up all my spendy factory 200gr accubonds I bought last year and I still haven't had time to work up any handloads to REALLY shoot it. The next step will be loading up some 220 gr GameKings I have, then I'll run some rounds through it.
PS, there was guy or two around here in Fairbanks who have Kimber 325's and this winter we talked about hooking up and doing direct comparison of a magnaported and non-magnaported gun. Let me know and we'll go do it.