Well, since I started shooting DCRA when I was sixteen, I have a quiver of LB and DCRA rifles and enough parts to build several more I think I have a rough idea what I am talking about. The question was about a "Lee Enfield target rifle chambered I 308". That would tend to mean a DCRA conversion rifle or equivalent in this country, Canada, that is. My statement "not intended as repeaters, the mag was used as a loading platform" is entirely true and correct. Of course there were repeaters built on the #4 but very few were used for this purpose as all TR shooting done under DCRA rules was single shot. If I were to dig out old rule books I might even find that the use of a magazine was not allowed but I am not sure on this and don't want to waste the time looking!
Cheers!