Lost Lake, here are some average velocities for a few of the 124+P loads from a Glock 26,that I ran a couple of years ago. These are just the averages,I won't post every round:

Speer Gold Dot 124+P: 1200fps
Rem.Golden Saber 124+P:1124fps
Win.Ranger RA9124TP : 1181fps

All these are are recommended 9mm loads and perform well. I did not have any 124+P HST's at the time and only ran the 147 which averaged 949fps from the G26's 3 1/2 in barrel with expansion of .69 in the medium.

I have considered staying with the 147HST for the Shield,but may use the 124+P,depending on how things look when I have a chance to properly test and chrono some loads from it.
You can't really have "fail" with any of the premium loads,even from the 3.1 inch barel of the Shield,but some may perform better than others,and I have a sneaky suspicion that a 124+P may be better in this gun.
The bullet designs we have now make quite a difference,also.Velocity is not the big bugaboo that it once was,but I still think it can help with these barrels less than 3 1/2 inches.
If you look at my velocities for the Gold Dot and compare it to what JimC posted for the three inch,it appears that it falls right in line,with not much loss in the three inch.
Most times you have to give up a little something( velocity,but not much) in order to gain something else(portability,concealability).

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Blessed be the Lord,my Rock