I purchased one, for my 7400, a few years back, and it worked well
for about the first 6 or 7 rounds, and then it had feeding problems.
I personally would not waste my money on another one. Of course,
I own a couple of AR-15's, with a pile or 30 round mags, that do
feed reliably :-D . I don't think I would want to put my life in
the hands of a Remington 742, with a finicky feeding 10 round
mag.
Also, if I remember right, my 7400 was slinging slugs into about an
8" group, by the time I got to the bottom of that 10 round mag,
from barrel heating.
I think if I were to be thinking of using the 742 in combat, I'd
get a bunch of 4 round mags, or better yet, buy a cheap AK-47.
The 742 will be about as accurate as an AK, after about the 5th
round, and no where near as reliable.
Squeeze