The Titleist 716 AP2 irons feature a very different look to the previous 714 AP2 because the bar that sat across the back has been moved down diagonally to create a larger pocket cavity in the back that is enclosed unlike the AP1 716.
The bigger change is one you can't see. The previous AP2 irons had tungsten weights in the heel and toe to increase the stability of the irons and in the AP2 they are still there, but now there is more of the heavy stuff.
In fact the 716 AP2 irons have 56 grams of high density tungsten in the heads of the 3 to 7 irons that is co-forged into place. In this process the head is forged and then the tungsten weights are added onto the frame of the head and then forged into place, so no screws or glue are used.
Aside from that the 716 heads are the same shape and size as the 714, with a medium width top line, a touch of offset and a mid-sized profile.
What the new head style and the extra tungsten does is to lower the Centre of Gravity (CG) so that it is closer to the impact point of the ball on the face.
On Trackman this shows up as a slight increase in the ball speed because you are getting more centre strikes. It also helps the accuracy thanks to the higher MOI from the heavier tungsten weights in the heel and toe.
For me when Trackman measured the 714 and 716 AP2 6-irons in the same shaft, the carry distance was pretty much the same. The 716 AP2 irons don't feel any heavier to swing, but you can feel the benefit of the weight being lower down as they do feel a little more solid than the 714.
If you are between the 716 AP2 and AP1 then the big difference is the feel from the forged faces of the AP2, which give a lot more feedback and sound better too.
This continues through the set even though the 8 to PW do not have any tungsten in the heads. I am sure if they had not stamped 'Tungsten' on the 7 iron upwards it would be very hard to tell anything was different.
In the shorter irons the mass is greater lower down for the head size and the extra loft means it is better to have the sweet spot higher so that is their reason for leaving it out.
The AP2 lofts are the same as before, but as the AP1 716 lofts are cranked up to cope with the faster faces, there is 2° to 3° difference between each club so blending the two sets is pretty much out. It is also one of the reasons I would stick with AP2 if you already play them, as the AP1 wedge is 43° and leaves a very awkward gap to the 50° wedge that you have to fill, compared to more consistent gap from the 46° AP2 wedge.
However the only exception to this would be at the other end where, like Zach Johnson, you could swap the AP2 4-iron for an AP1 version, which is not only more forgiving, but the feel is pretty similar even if the sound isn't. It's a set up I have been testing for this review and the extra yardage from the AP1 4-iron helps the gap to my hybrid, but looking at the larger offset takes a bit of getting used to.
The soles of the 716 AP2 still have the pre-worn look and the trailing edge as a little camber on it to help it go easily through the turf and it is hard to spot much difference here from the 714.
Overall I think the 716 AP2 is a step forward from 714 and the lower CG point and extra stability is noticeable without compromising on the sound and feel. As a forgiving better players forged iron, the 716 AP2 is one of the models to beat in the market.