My first 309JDJ was a blued TC factory 30-30 Super 14 that was rechambered by SSK. Did not have a brake of any kind. Per JD himself, he said to reduce loads from his published data for the SSK 309JDJ in the TC barrel. Been a long time ago now, so can't remember how much he said to reduce by, but I never tried full house loads in it becasue I also had an SSK CM 375JDJ at the time. BTW, he stamps SSK on the lug of the barrels his shop rechambers, so you'll know if he did the job.
Next I had an SSK chrome moly 14" with the 4 port Mag-Na-Port, and now I have an SSK stainless 14" with full length T'SOB rib and no brake (one of a matched set of 4 - 257, 6.5, 309 and 375 JDJ's).
Don't know if any of that helps you, but JD is only a phone call away.
Ladobe :bye: