I have a customer who is interested in buying a 45 ACP semi auto with a threaded barrel that he can use with a suppressor. The Glock 21 Gen 4 and SF is too big for his hands so I wondered if the S&W M&P 45 is smaller than the Glock 21SF Gen 3?

Thanks for your help guys!

The M&P45 is a smaller grip and the different size grip straps make it a good choice.  I started using the G21 many years ago but the grip is too big for me so I put Hogue slip on grip sleeves on mine.  They do make the grip a little bigger but it makes it MUCH easier to grip well.  I use a Hogue on my Beretta 92A1 also for the same reason.   It's a great way to allow smaller hands to use large grip guns.

M&P45 is a lot smaller and more comfy than the 45/10mm frame Glocks

IIRC the small backstrap on an m&p 45 will be roughly the same size as the medium on a 9/40.

The m&p 45 fits me great (dad has the compact) but any of the glock 45s are much to large.