It may grab hold and tear patches with patched round balls and will fill with lead with conicals. Is it safe ? Sure , no safety issues, I can think of. Will it effect accuracy ? Maybe , maybe not; have to shoot it and see.
As a side note, all gas operated rifles (AK's, SKS's, AR15's, etc.) have a gas port drill in the barrel 6" to 10" from the muzzle; and many pistols have ported barrels. However those use jacketed bullets not soft lead and pillow ticking.
On an unrelated note, the machinist in me can't help but notice the massive burr under the flat on the nipple. Tool life is real, endmills are cheap.
As a side note, all gas operated rifles (AK's, SKS's, AR15's, etc.) have a gas port drill in the barrel 6" to 10" from the muzzle; and many pistols have ported barrels. However those use jacketed bullets not soft lead and pillow ticking.
On an unrelated note, the machinist in me can't help but notice the massive burr under the flat on the nipple. Tool life is real, endmills are cheap.