No, it means that you must be carefull reloading as a double charge is something tha can easily happen! Just about all firearms manufacturers do not warranty ANY firearm that shoots a reloaded shell! I have seen commercially reloaded pistol ammo with a triple charge detonate a revolver. There were other loaded 38s with triple charges in the lot!
Example, a double charge of powder in a shotshell and the wad does not fit. Forgo the wad, it must be there. Load and crimp. Bang, the barrels blow off for to much pressure. I can't get a Win 209 primer, I use someone elses. I can't get clays but I will use an equivalent. I don't bother to weigh the charge because the bushing says 18.5 gr. I will use some other wad and not the Winchester one. End result, one over pressure load that can distroy a shotgun.
Factory loads are test fired several times per lot. They are pressure tested. They are chronographed for consistency. They are patterned. They are loaded just ONCE. They have liability insurance!!!!!!
And the reload?............
It is no wonder that the firearm manufacturers will not warranty any firearm that has shot a reload!
The Lone Canadian,
Henry
PS: I HANDLOAD (weigh and check every round!) target munitions for my pistols and rifles.