Oh jeeez... You completely not understand what blow off panels is, do You?
Blow off panel as is name suggest, is meant to be blown off the tank in case of ammunition cook off to free pressure and fire away from crew. So what these small caps are mean to be blow off inside crew compartment, killing loader and later pressure and fire killing rest of crew and destroying vehicle? Briliant logic I must say...
Blow off panels are allways placed outside, acting as roof for ammunition magazines.
As for Arjun, sorry Kunal, more and more sources seems to proove that turret ammunition magazine is unprotected, not isolated, and is dangerous for crew. Even if these caps are used, they IMHO won't help much.
As for an artillery rounds photo above, nope, it is not the same, because these containers are used only for transportation on trucks and such things.
BTW as for M1A1/M1A2, sayareakd, not only M1 series got such ammunition storage system, but especially M1 series, as whole ammunition is stored that way in this tank.
Turret right and left ammunition magazines with their blast doors closed.
Drawing for loading procedure.
Ammo placement.
Drawing and photo of hull ammunition magazine with it's blast doors opened.
M1 hull ammuniton magazine blow off panel. Thanks to Grendel, user of IOH forums for photo.
Turret ammo magazines blow off panels.