I just read a thing about using an offset pin to put together a small pin upper to a large pin Colt lower. The article stated that when doing this, be careful to always start with the rear take down pin while either putting on , or taking off the upper. It says you can stress your lower holes to the point of breaking them off. Is this correct, and does this mean, you now cannot just break open your rifle to clean?,,,,, you have to always remover the entire upper to clean your rifle as not to stress your lower holes and break them off?