The line-of-sight with the receiver sight is higher than with the open/iron barrel sights; so you need to replace the front sight with one that's taller than the issue sight.I installed the FP rear this week and figured I'd test get some reference groups with the factory front sight before doing the replacement upgrade to the 17A.
Well what I'm seeing is that my rifle is shooting a full 12" high at 50 yds with this set-up. ( 6" at 25).
Here's a handy sight height calculator:
Sight Correction Calculator | Top Rated Supplier of Firearm Reloading Equipment, Supplies, and Tools - Colt (brownells.com)