I had the same problem in .243 and although the Fedral grouped very well, the Norma are a tad tighter. I found the Norma's grouped slightly higher, 1/4" maybe @ 100yrds. I use the Norma 58 gr BT's in .243 for Charlie, a lot faster (3750 fps) very flat shooting, totally devastating, far more suitable for Charlie, I would use these over the 100gr sp tbh. These group an 1" higher over the 100gr SP's, perfect.
In answer to you question, always check zero, when trying different ammo or even changing batches if you feel the need.