do they make a wolff spring for the ush 12 ga. where to purchase and could i replace it or do i need a gunsmith.my issue is i have a ush that has only been fired about 15 times and already had a misfire with a light strike.it could have been a bad shell,not sure,the primer was recessed a little and was not flush as was the other shells.also had a friend try it in his ush and it also did not fire,this led me to believe it might have been the shell and not the gun but with past issues i have read i want to make sure it is not the gun,i think i purchased the gun in 2008 so it is not an older model if that would have anything to do with it if there has been any improvements made recently, thanks