خمپاره با موشک کالیبر بزرگ بهبود یافته

After all, I understood that it is not a device launching bombs, but it itself is a kind of bomb, as wikipedia defines it as follows:

Lob bombs (known officially as an improvised rocket-assisted mortar,[1] improvised rocket-assisted munition,[2] or IRAM) are propelled by 107 mm rockets and launched, several at a time, from the backs of small trucks where they are arranged in rows,[5] sometimes by remote control.

I also think that "large caliber" is an adjective phrase for that bomb, not the rocket. Therefore, if we put "کالیبر بزرگ" at the end, it may make ambiguity whether the bomb is of large caliber, or the rocket.