Under the heading of "Why hadn't I already done this?" was a comment that asked "How do these work in .303?" Well, now I have an idea
X-Treme 7.62 plated bullet, 123 grains, over 15.0 of 2400 powder, fired from a #4Mk1. This is definitely a 'Make some more for when can get to the outdoor range', so can try them at 50 and 100 yards from a solid rest.
First was low. WAAAY low; using the large 300-yard aperture it hit below the bottom of the outer ring, so flipped up the ladder and cranked it to 500. Which will probably, if past experience is any guide, put these pretty much on at 100.
And, in another test
When I can try them at the other range, I'll try to get chrono readings, too.