We had a few Mossberg 590A1 14" guns pass through our store with less than admirable front sight assemblies. Unfortunately, that is how these guns arrived form Mossberg themselves.
OP, if your front sight requires inspection or adjustment, the firearm must be returned to the authorized Mossberg warranty centre for inspection and repair. That centre would be Grech Outdoors, located in Mount Forest, north of Guelph. Contact John Grech at 519.509.4867 to make arrangements to ship the gun there if it does require servicing.
As for the magazine detent ball and spring, Grech can also replace those parts under warranty. Again, please contact Grech for availability. If you are not sending your shotgun to Grech for servicing, they should be able to send any parts that you require out to your address at not charge. You will need to make those arrangements through Grech.
Now, I know that this post will raise all sorts of complaints about poor customer service, or how Epps should simply exchange this gun for another, but the truths of the matter are these:
1) We do not have any more of the 14" 590A1 shotguns available for sale or exchange. The guns we DID have were a one-time limited run of these firearms from a contract that was cancelled by a third party. No further examples are slated to be released in the foreseeable future.
2) Warranties must be handled by the authorized warranty centre. Period. This fact has been discussed to death on various forums around these boards.
OP, let me know if you require any further assistance. You can contact me by PM here, or at my Epps E-mail address at
info@ellwoodepps.com, at your convenience.