Due to a past shoulder injury and still wanting to compete in two gun matches, I was looking for a softer recoiling bird shot ammo and I heard that Aguila made short shells so I looked into it.. Unfortunately, they will not feed into most pump or semi autos correctly. Fortunately for me,, there is an adapter manufactured by Opsol based out of Texas that will allow correct feeding if you have a Mossberg pump action shot gun. Lucky me, that what I have so I bought the adapter for $15 and 100 rounds of the ammo for 40 cents a round and headed to the range.. The installation of the adapter was easy peasy, it just slides in..These short shells are amazing, the felt recoil is at least half and the Mossberg pump feeds them easy with no problems. Lots of Up sides here,, I can now load 9 shells as compared to 5, that's good for competition or home defense. If you have a single shot,double barrel or over under, these will help with recoil sensitive people like women, pre teens or wimpy people like myself..Hope this helps..