This was quite a massive gun. The long barrel accelerated 43 kg 152 mm shells to about 900 meters per second. As for its destructive power, I will let these photographs speak for themselves. (Source: CAMD RF 38-11369-304).
150 mm plate. Shots 1-4 were fired at a 30 degree angle. Shots 5 and 6 at 0 degrees.
180 mm plate. Shots 9-12 fired at 0 degrees. Photo #5 shows the front of the plate, photo #6 shows the rear.
203 mm plate. Shots 13-16 fired at 0 degrees. Photo #9 shows the front of the plate, photo #10 shows the rear.
As devastating as the BL-8 was, the design did not satisfy the RKKA. Work on a powerful gun continued, and the BL-8 was further improved to become the BL-10 (the BL-9 index was taken by a 122 mm gun). The BL-10 was mounted on the ISU-152-2, also called the ISU-152BM or ISU-152-10. By that time, the war was coming to an end, the Germanic gigantism proved to be containable with the D-25 gun, and work on a high power gun of a large caliber ceased.
ISU-152 with a BL-9 (OBM-50) on top and a BL-10 (OBM-53) gun on the bottom.
CAMD RF 81-12038-268
A number of these guns were produced throughout the development process. You can currently find a BL-7 gun marked #4 in the Armed Forces Museum in Kazakhstan.