I've seen three rifles mentioned here that I literally just shot today. My last two purchases were a CZ 452 (got that one new) and a Remington 552 (used from a pawn shop). We were shooting today and my oldest's Henry came along too. Fun way to spend an hour at the range (indoor, 25-yard max).
Ok. Back to topic.
I can say that, other than a little stiffness of bolt being new, the CZ stuff is amazing - stunningly accurate even with open sights. So much so that even though I wanted the open sights (the tangent rear sight is cool), I am now thinking some sort of tip-off scope mount so I can do both interchangeably. No knowledge about CZ semis, though.
Perhaps more germane to the present discussion, I can say with authority that, especially if clean, the Remington 552 can definitely shoot LR and Shorts (I didn't have any Longs). Story follows...
I got one this week and cleaned it this morning before going to the range (by the way, yes, you do have to remove the barrel to get to the bolt, but no, it isn't too much of a pain). According to the barrel code it's either a 1998 or a 1969 - it looks more 1998-ish to me. This noted, given how much crud I cleaned out of the receiver, end of the barrel and trigger group, maybe it is a 1969, but I digress (again).
I first ran LR's through it (Federal Auto Match). Grouping was a bit to the right of center (probably knocked the scope a little off when cleaning today), but it was a tight group, for both my child and me. 10 rounds, nary a hiccup. Next I ran Remington shorts, which I believe are high powered (I don't think I have any shorts that aren't) . 10 rounds, all chambered and fired like clockwork.
Finally, I decided to really mess with it - 5 LR and 5 Shorts, alternating. LR, Short, LR, short, etc. 10 rounds, all like clockwork. Curious thing (to me anyway) is that the LRs and the Shorts all tended to group in the same place on the target.
Hope some of this helps.