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Winchester Responds to Online Postings Regarding Possible Malfunction of 12 Ga. Slug Ammunition in Mossberg 590 Patrol Shotguns

Police1 has been unable to verify the information in question. We contacted Winchester as part of this process. They have asked us to send out the below information to Police1 members.

We have become aware that certain individuals are disseminating information via the Internet about Winchester® brand 12 ga. slug ammunition malfunctioning in Mossberg 590 patrol shotguns.

We have investigated these rumors and have been unable to identify the source of this information and have therefore not been able to assess the situation described in these Internet postings. Furthermore, we have been unable to duplicate the described malfunction in our facilities with our own Mossberg 590 shotguns.

We have had one law enforcement agency contact us about feeding problems with their Mossberg 590 shotguns. However, those guns had had some after-market modifications and we are investigating this combination, with the full cooperation of the agency and Mossberg, to determine the cause. According to the information we have received at this time, the ammunition meets the specifications established by SAAMI, the industry association that establishes manufacturing specifications for small arms ammunition and firearms.

No other law enforcement agencies, including the author of the Internet postings, have contacted us to report any problem similar to the one described on various Internet sites.

We do want to emphasize, however, that we always recommend that all agencies maintain, test and inspect their equipment, including firearms and ammunition, regularly.

Police1 Note:
If you have any information regarding this issue, please contact Police1 at or Winchester at

The Posting in Question:

Potential Officer Safety Issue:

“We made a startling discovery yesterday that quickly developed into a significant officer-safety issue here. We just received a shipment of Winchester, low recoil, 1 oz. 12ga slug ammunition, which, for the past five years, has been the standard, issue round for our department’s Mossburg 590 patrol shotguns. As always, we tested several boxes at random prior to general issue. To our astonishment, our Mossburgs repeatedly experienced feeding failures! Rounds could be seen through the ejection port ‘dangling’ vertically, having ‘fallen through’ the shell lifter. Our hasty investigation revealed that Winchester’s new shells are one-quarter inch shorter than their previous version, and they are not now long enough to be reliably held on Mossburg’s skeletonized shell lifter. Winchester inexplicably made this modificationwithout any change in cartridge designation or stock number. The new shells did feed reliably in our single Remington 870, as it has a solid shell lifter. Our investigation led to a heated conversation with Winchester’s West Coast distributor, who informed us that Winchester shortened their shells to make it possible to charge a ‘four-round’ magazine tube with five rounds. A laudable goal, but they neglected to publicize this modification, nor obviously, test it in all major manufacturers’ shotguns. To reiterate, WE REGARD THIS AS A SIGNIFICANT OFFICER-SAFETY ISSUE, and the entire shipment has been returned to Winchester. That this new ammunition will find its way into a Mossburg shotgun, owned by a police department, is inevitable. Winchester needs to recall this stuff and immediately return all production to original dimensions. If all ammunition manufacturers decide to go to this new dimension for 12ga shells, then Mossburg will have to redesign its shell carrier, so that it will reliably capture these shorter rounds.”

Lesson: TEST YOUR EMERGENCY/SAFETY EQUIPMENT REGULARLY! Winchester is a fine company, but a faux pas like this is going to happen every now and then. In this case, the problem was discovered and corrected immediately (at least in this department). Had it gone undiscovered, it may have resulted in an unnecessary injury or death. Serious gear needs serious attention!” Forwarded by Hank