"hardware implication"
View attachment 87911
""" "hardware " implication of increasing the internal bore or caliber or tube artillery. """ what does that even mean.
do you mean the technical changes required or engineering challenges; again mechanical/structural challenges for launcher platforms and tubes? or electrical and electronic hardware? data links for guidance systems? change in aerodynamic profile for increasing launch velocity of rocket(for higher range) & decreasing drag?
you need to be atleast clear in asking questions.
just for your reference of pinaka mk-2 rockets.
solid rockets motors (motor is the technical name) are able to achieve some 2.5- 2.8 km/s of exit velocity.
pinaka has a solid mono cylindrical propellant. it is unknown about the internal grain shape since such data is not made public. however an assumption can be made about its thrust profile it could either be a "progressive" thrust cylindrical cross section or finned cylindrical cross section.
also the nozzle design is extremely important.
the most prominent design is the de-laval nozzle
View attachment 87913
its external profile or shape can be approximated into cones for easier calculations.
View attachment 87912
reference photo from our courses...
note that ; the above de laval nozzle is if the exit velocity of burned mass is greater than mach 1. M > 1
the higher the mach number, the Area of cross section of diverging nozzle end will be much higher.
for M< 1, Area of diverging nozzle Ad <<< Ac area of converging section.
thats why pulse jet engines have smaller ends and larger inlets. thats why jet fighters during takeoff have smaller ends in their variable nozzles and the cross section is maximum when fighter jets cross mach 1.
nozzles have similar principles for both turbo machinery planes and rockets and also both solid motor(propellant), liquid motor, or hybrid motor.
the entire nozzle structure is fit into a cylinder tube for easier launch thats why you don't see the nozzle. cuz its internal.
View attachment 87918
pinaka mk1 rocket. notice the end section.
increasing the caliber increases the size of nozzle too. also if L/D ratio (length /diameter of rocket superstructure) is increased, more exotic materials need to be used. which increases cost.
so increasing caliber or bore while keeping L/D ratio same is generally preferred.
for hypothetical example 200 mm caliber, 5 meters length . L/D = 25.
so for 300 mm caliber, the length would be 7.5 meters.
but there is a problem. the thickness of the superstructure increases( outer dia of rocket -(minus) outer dia of the propellant -(minus) thickness of abrasive thermal sleeves).
thermal sleeves prevent the superstructure from being destroyed mid flight.
that thickness should be able to hold compressive stress under normal static condition and also during acceleration condition since extra pseudo force acts if the rocket is accelerating. constant acc. or increasing acc. again depends on grain shape of the rocket. which once again affects the propellant mass.
it should hold the bending stress.
View attachment 87922
reference purpose.
after that. it also needs to hold the torsional stress. (twisting stress). why you ask?
because generally rockets are unstable. and fins are added to provide good stability. larger the fins, better stability. however larger the fins, increased viscous drag from air. cause air is a fluid just like any other gas.
so to prevent that, the motor exhaust are designed such a way to provide spin stability.
in gun artillery, the barrel has rifling so the shells spin during its projection, throughout the flight.
in tanks, we have the new smooth bore guns, but they can fire only fin stabilised HEAT and APFSDS. cannot fire ordinary rounds.
so the rockets are generally spun by angling the exhausts. in the case of pinaka mk-1 and 2, there are folded fins. as observed in the above images.
so, for extended range spin stabilised rockets, the superstructure needs to hold torsional stress also.
View attachment 87924
you don't want the superstructure to twist itself mid flight due to extreme speeds.
i can go in a lot detail. but i am sure you understood the '''" hardware implications" ''''as mentioned by you.