Many are probably going to scream and rant about this, but here goes.
For practice, just use 55gr ammo!
The difference in POI at 300 FEET is only 0.6" - a little over half an inch.
The Hornady 75gr TAP bullet has a Ballistic Coefficient of 0.435 and a published Muzzle Velocity of 2790 fps. After the bullet leaves the muzzle, it will drop 2.3" at 100 yards and 9.9" at 200 yards. This does not mean this is where it will hit when you shoot from a zeroed weapon, but just the bullet drop.
Federal American Eagle 55gr bullet has a Ballistic Coefficient of 0.343 and a published Muzzle Velocity of 3240 fps. After thisbullet leaves the muzzle the bullet drop will be 1.7" at 100 and 7.5" at 200.
I call this difference close enough for practice. The differences in POI will be even less under 100 yards.
Now, having said all that, I can tell you that in MY 16" Colt with 1:7 twist the POI difference between Hornady 75gr TAP and Federal 55gr XM193 out to 200 yards is within the differences I cited above.
The XM193 does, however, shoot about an inch left at 100 yards.
Your particular weapon may (or may not) demonstrate a difference in windage POI and should be tested. But for these ranges, there is really no reason why you can't practice with 55gr ammo and carry the 75gr TAP ammo.
HTH