In the late 80's I used to shoot long rolls of 35mm in a 250 exp back. I'd send the film to a pro lab in Dallas that would process the B&W film and return it sleeved, no prints. I'd then make 8x10 contact prints myself.
Anyone know of a lab in the USA that can still process 30 feet of 35mm B&W film? I'd like to use my 250exp back with my OM-2 cameras again.
I've lost track of most of the mo-pix labs in the South, but Colorlab in DC still offers B+W 35mm processing in D96. (I used them a decade ago to scan and transfer my grandfather's 9.5mm Pathe home movies, as they were the only lab in the US to offer that service. Very happy with the service then.)
I ran into the same problem last time I used my bulk back on my Minolta A9000, in the end I just sacrificed a frame as the I cut the roll at the of each 36 exposure reel.