I have no issues shooting my 1911 which is a RIA  FS Tactical II.. niether does my daughter. we are both short with short fingers... my son on the other hand is well over 6 ft and has long "piano" fingers as I call them... today was his first time shooting my 1911, he got a blister in his trigger finger ( the trigger face is textured)  and the ambi safety really dug into his hand while shooting... I know I can change out the safety and solve that issue, but why would the trigger be leaving his finger pinched/blistered?  oh, he is an avid shooter and has no issues with any other of my handguns... anyone else ever have this happen with the 1911?  thanks

Find the area that is giving him trouble and sand it smooth with fine sanding cloth and apply cold blue and on the trigger just polish it, it'll look awesome. Buying a new safety may not help, even some expensive safety's may have sharp edges.

I've never had that problem with any 1911. If it's your gun and it doesn't bother you I wouldn't worry about it.

I'm guessing he is pulling more to one side than straight back on the trigger so his finger is rubbing the sharp outside edge of the trigger.  I know the outside trigger edge on some of my 1911's is really sharp.  Maybe have him move his trigger finger more to the tip of the pad and see if that works.  David

Both my ria had sharp edges. I took a some 500 grip sand poet to them and then polished them out. Much softer corners.

Also I just removed the left said safety lever with no issues. I know you are supported to replace that safety and pin set but I didn't and it works fine

It's probably a grip issue with him getting his alien fingers on the trigger with his second knuckle.