Scored some 45 for my new SAR-K2. It's Federal-230gr-FMJ RN.

Noticed the following on the box:
"Do not use in firearms with ported barrels or ported recoil compensators"

Any ideas on the reason(s)?

The bullets are plated which is thin and may be peeled off by the ports. This may result in spittng bits to the sides.

Many moons ago I shot some Blazer aluminum .357 in a Rossi 92. 1st shot the case split in the chamber and I had to get a rod and back it out in shards 2nd shot did the same. Looked at the box and it specifically stated NOT to use in rifles. I don't know if it is still the case but I read the boxes more thoroughly now.