Gun Review: FN 503

posted on September 29, 2020

The idea of a daily carry pistol is now so common that it passes without notice in many circles. As the weather gets hot, those who do everyday carry look to find something smaller and lighter. And those who carry a backup always want something smaller and lighter. 

Enter the FN 503, which is just about as small as you can make a striker-fired pistol and still have it hold six rounds of 9 mm ammunition. The small size does require some compromises, which, for starters, means less capacity than a wide-body 9 mm. The 503 comes with an eight-round magazine, should you need the larger size, or want eight rounds on your reload from the first six-plus-one.

The FN 503 is about as flat as you can make a 9 mm pistol, and still have it operate normally—the 503 is a decimal point greater than one inch thick. 

FN503 sights, trigger

Its relatively blocky slide has a bevel on the sides at the muzzle to allow for easier holstering and re-holstering. The slide holds the striker mechanism, as there is no room in a pistol this compact for a hammer. The top of the slide has a compact set of fixed sights. They are each in transverse dovetails, and they can be drifted laterally to adjust windage. Should you need an adjustment in vertical impact, you’ll have to swap out the front sight for one shorter or taller.

The sights use the same-size dovetails as those on the FN 509, so you have a wide selection of options, both from FN and from aftermarket sight makers.

On top of the slide is a loaded chamber indicator—this is for those who use them and for those jurisdictions that require them.

The extractor is robust, and the ejection port is large, so extraction and ejection should not be a problem, nor were they in testing.

FN503 specsBehind the extractor and ejection port, FN has machined cocking serrations into the slide. There are six wide, shallow rectangular grooves. There are no serrations on the forward part of the slide. 

The barrel has an integral feed ramp, so smooth and reliable feeding is a given, and the muzzle is machined with a recessed target crown to wring as much accuracy as possible out of the pistol.

The striker mechanism has no external thumb safety, but there is a trigger safety in the center of the trigger blade. Until that is depressed, the trigger can’t travel far enough to cock and release the striker. The trigger and the parts that lead to the striker are all made of metal. This means the 503 does not give the “polymer squish” on the trigger press that plastic triggers can sometimes have. The trigger pull is cleaner and crisper as a result.

The chassis of the 503 holds the trigger mechanism, the transfer bar, the striker cocking piece and the drop safety parts. The chassis is the firearm, and contains the serial number which can be seen through a slot in the molded polymer frame on the left side of the pistol. The slot is directly behind the slide stop lever, which is itself shielded on its front edge by a molded bevel in the polymer shell. This acts to keep a holster from pressing on the slide stop, and also will reduce the amount of lint and other debris that might build up there.

accuracy chart

The chassis is pinned into the polymer shell, and is not meant to be removed.

The magazines are held in place by means of a latch located behind the trigger guard. The release button is also shielded, as it is recessed in a groove in the molded shell. It is thus highly unlikely to be pressed when in a proper holster. (And everyday carry pistols should be in a holster, secured to a sturdy belt. There are plenty of holsters available for the FN 503.)

The six-shot magazine has a small finger lip on the front of the baseplate, so your hand can have some leverage to handle recoil.

The frame is textured for a non-slip grip.

As you would expect from a pistol this size, its recoil is snappy. The felt recoil is as much a function of the size as it is the weight. The felt recoil, however, is an unavoidable price for something so compact and easy to carry. With a proper grip and some practice, the recoil becomes just another part of marksmanship.

As an ultra-compact daily carry pistol, or as a backup to a bigger one, the FN 503 is an excellent choice.


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