Given today's skiddishness about pressure & with the testing equipment available today, I'd be very surprised if O'Connor's loads, like some of Hagel's & Keith's, wouldn't be considered "over-pressure".
MM
I say,
HERESEY! I say.
From personal experience I use & used 3 of JOCs loads w/o any problems at all.
A. 62 gs Surplus 4831 with 130 HSP = 3100 fps. 270 Win obviously
B. 49 gs IMR 4064 with 130 HSP = 2900 @ fps 270 Win
C. 52 1/2 gs IMR 4064 with 150 HSP or SSP = 2900 @ fps 30-06
I had my own Oehler 33 before I found Hagel's book, "Game Loads & Practical Ballistics........."
I also used 'many' of Bob Hagel's loads in diff cartridges. By many I mean loads for 243 Win, 270 Win, 7 mm RM, 308 Win, 30-06, 300 W M, ETC. I can honestly say, NONE of his loads **that I used** produced expanded primer pockets, blown primers OR excessive short case life.
I AM aware that he was KNOWN for excessive pressure use & destroying some rifles. I can't explain why NONE of his loads caused me any trouble. MAYBE, he had toned things down a bit before publishing that book ? ? ?
ALSO, I wish we had individual pressure testing equipment that was LESS technical & less complicated to use. I have a Pressure Trace system but it is old enuff that it is NOT compatible with TWO computers I have tried.
Jerry
