I learned in an earlier thread on the Milsurps Soviet rifle forum that there was a commercial concern in Canada (where evmoor is located) by the name Of "Globe", IIRC, which converted quite a few SVTs to .303 SAA, I don't remember if they kept the brakes intact or no; I'll see if I can hunt the old thread down later. (It was concerning the fluted chambers of the SVT and possibly a thread I started...)
Oh, BTW, not likely the brake above retains it's threads- they were further back than I remembered. Did get some photos done of the area on a SVT- will try and post reasonably soon. The SVT40 I weighed comes in at 8 1/2 pounds empty with magazine- pretty dang light. Will try and sample some more.