Thank you for the concern: basically once the Magnetospeed is on it is fine, second I remove it the rubber for larger barrels pops right off. I will get that to you ASAP.
EDIT: I looks like the grove the little bars on the back of the rubber inside the Sporter are not quite snug enough. It is not an issue because I know about it and can keep an eye on it. It only happens when attaching or detaching it from a barrel. I will send photos anyways due to your awesome customer service concerns.
P.S.: The Sporter fits awesome inside a 14" (overall outside length) pistol rug/case if someone is looking for a cheap option better than the factory box.