Welcome Claypij, the 22lr rounds that I know of with a headstamp "F" are by Federal. With the Federal Punch FMJ it may be due to nickel plated rim and LOW muzzle velocity.
If you have any of the "F" marked bullets go here 22 Ammo, 22 LR, 17HRM Ammo | Federal Premium and compare the bullet to their round nose copper bullets.
I would also measure the rim thickness of the "F" bullet with calipers for future reference and comparisons.
It also very well be a matter of using bullets with a higher muzzle velocity to eject better.
If you have any of the "F" marked bullets go here 22 Ammo, 22 LR, 17HRM Ammo | Federal Premium and compare the bullet to their round nose copper bullets.
I would also measure the rim thickness of the "F" bullet with calipers for future reference and comparisons.
It also very well be a matter of using bullets with a higher muzzle velocity to eject better.
