The AP1 heads are 431 stainless steel while the AP2's are a forged 1025 Carbon steel. It takes more time to produce a forged head over a cast.
Cast - Made by pouring hot/melted metal into a molded form of the club head.
Forged - Made by taking a raw block of carbon steel and pounding/compressing the metal to form the club head.
AP 1 irons are easier to hit than the AP 2 by far. PGA pros may use AP 2 but AP 1 is for people with handicaps like 15 or above.
AP 2 be grand for you according to reviews.!!!I played off 9 a few years ago but now am a 12. I was going to go AP2 also but have not hit them yet.I hit AP 1's tonight and they are great.Not a high handicap iron IMO. I reckon for someone between 8 and 14. Lovely irons.