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Any one have exp with it? How does it compare to the full size? I know that it's a half inch shorter barrel. Looking at replacing my 1911 and m&p 9 for mid or full size 45.
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Magazine capacity. I realize you are coming from a 1911 so the capacity doesn't bother you that much but don't pigeonhole your self. One of the biggest advantages of switching from 1911 to polymer is the increase in capacity. I wanted to upgrade from my XD45 4" and gave the M&P45 a good hard look. The only thing I had issue with was going from 13+1 to 10+1. I ended up going full size / full retard and bought an FNX45 with 15+1.
As for the M&P itself I have yet to fire one but I went to the armorers school for it and was very impressed with the design. It was in that school that I decided to switch out my XD, having seen what other manufacturers are doing. I doubt this is the information you were looking for when you started this thread but it's all I have to offer.
My input: I'd definitely upgrade but, if you intend to go .45, due to magazine capacity I wouldn't (didn't) go M&P.
Eta: the M&P45compact only holds 8+1 btw. Forgot to mention that.