Has anyone one run into any issues with ammo jamming in their Saint AR's? I've had issues with 1 brand only, thought it was a fluke type of thing but at this point have decided to avoid that brand altogether. I've never had any issues with any other brand, just this one brand. It is Armscor 55gr FMJ and bought it because it was on sale at a local farm and ranch store. Armscor has been great to work with. The round gets jammed and won't fire, and I have to "mortar" the round out. Not my favorite thing to do. I've noticed that this style of their ammo that the neck of the casing is slightly thicker than the other brands that I have like Frontier, Winchester and Federal, thus probably getting stuck in the chamber.
Boccat93, unless your gun is problematic with either -ALL- or a majority of varying brands and grain weights (lengths) of .223 and 5.56 ammo out there, I honestly wouldn't worry about it.
Why?
Because of tolerance stacking.
While both the gun and the ammo which is fed are products of exacting modern manufacturing, they do each have their own tolerances both as mechanical systems themselves and as to how they are each manufactured. As a result, the very real-world phenomenon of tolerance stacking - which is what we in this hobby describe as the combination of various parts' dimensional tolerances interacting in a way that ends up causing a problem
- will occasionally rear its head.
Search around on various gun Forums or other social media, and you'll routinely find reports of unique weapons "not liking" a unique make/model of ammo.
What do I mean by "unique weapons?" I don't mean all Springfield Saint X or Y model. Rather, I mean that specific and unique Springfield Saint Victor Rifle that you own (I'm not sure if this is what you own, I'm just using this as a specific example) - not the Springfield Saint Victor Rifle that your brother-in-law owns. Not the Springfield Saint Victor Rifle that your local shooting instructor owns. Not the Springfield Saint Victor Rifle that's still sitting on the rack at your local store where you bought yours. Your specific copy, the one with that unique serial number which you filled out a 4473 for.
I have four 9mm XDms. One of them does not function well with Magtech 115 gr. range-fodder - it sometimes fails to cycle far enough to strip another round off the mag. Another one locks up so tight when I do malfunction-medley drills with once-fired American Eagle 115 gr. brass case that I literally have to mortar the gun to extract that piece of spent brass.
Similarly, when my buddy put together his Gen3 G19-based Roland Special, I met him at the range with 16 (sixteen!) different makes and models of new factory 9x19 - of that, his gun only misbehaved with one: and at that it wasn't even a functional problem, it just failed to group well with that one ammo out of the sixteen I brought along to test.
AR-wise, my Daniel Defense is perhaps the most ammo-tolerant of all of my ARs - to the point that it'll even reliably function brass-case after having shot hundreds of rounds of steel case immediately prior, and then back again. Meanwhile, one of my BCMs actually loves bulk 55 gr. ammo, often shooting it better than comparable 62 gr.
It's honestly completely OK - and actually, truthfully, not at all unexpected - that any one unique gun may have issues with any one or even a few specific makes/models of ammo. Just make a note of it, and not feed this particular gun that/those ammo, unless, of course, you *do* specifically want to practice reducing spontaneous stoppages.