To give you a rough idea of the size of FN's new Reflex, here it is next to the 509 Compact MRD. (The Compact is wearing an optics cover plate from a 509 Tactical, hence the protective 'wings' on either side of the rear sight blade.)
The 509 Compact is FN's rough equivalent, size-wise, to the Glock 26. The barrel is slightly longer than the Glock's (3.7" vs. 3.4") which gives it a usefully long accessory rail, unlike the baby Glock. A TLR-7A fits it perfectly.
Unlike the 509 Compact and the G26, both of which are essentially shortened versions of their respective makers' duty pistols, the Reflex is a different pistol mechanically. While it's externally styled to give a family resemblance to the striker-fired 509, there's a hammer inside. It's less than an inch smaller in every direction (a 3.3" barrel, for instance) yet it still has enough rail to use a TLR-7 Sub and only gives up a single round of capacity to the Compact: 11+1 rounds versus the bigger blaster's 12+1.
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