[HorseSoldier]

Also how many shotguns would be in Company size unit? I mean by t2k these weapons could be used both for hunting purpose and close-quarter fighting. I can even see at Company level or higher having some hunting rifles for the same purpose. So as not to waste military ammo for game hunting.

Depending on the MTOE, probably none in the T2K timeline (though the basis of issue for the HK CAW is an open question).

Real world, in the SF unit I was in we had about a million shotguns on the inventory. No idea who they belonged to on paper (ODAs versus support units, etc.) but in practice three per ODA for ballistic breaching and spares from there. In the current light cavalry unit I'm in we have (I think) eight for the troop authorized, though none on hand since shotguns are being issued above and beyond the authorized MTOE for conventional units down range, again for ballistic breaching.

How many non-authorized side-arms and abundant amount of SMG? Would troops who didn't have need or regular be issued side arms and/or Submachine guns would they be allowed to "borrow" them from elsewhere and keep them. Especially troops that Assault Rifles or Battle Rifle that have been in lot of urban built area fighting, might accept the extra weight for peace of mind having something they can handle more readily than their regular weapons. I mean the Machine gunner are issued side-arms for reason of self-defense at close range, but I can see them using them at times while clearing a house for use of outpost later where you don't want to tear it up too badly if you do find previous 'owners' still in residence.

Real world US military -- even white side SOF -- privately owned weapons downrange can be a career killing error, possibly even leading to criminal prosecution. I know some people whose careers in SF were essentially destroyed because they went downrange with personally owned sidearms that were better quality/better weapons than the M9 (well, because they got caught with them, anyway). Even the super cool kids on the black side do not, as far as I know, take stuff they bought themselves anywhere, they just are in units that have latitude to color further outside the lines on acquiring and issuing odd stuff.

T2K -- I think any unit with any motor transport to speak of would be a traveling bazaar of odds and ends, weapons wise. Guys who have to haul everything they own on their backs aren't likely to squirrel away a 9mm sub gun and a couple pistols and an AKSU and a nice 30-06 hunting rifle they happened upon along the way, but if you can chuck that stuff in the back of a truck or an APC it's wide open game on sort of stuff unless the command environment goes out of its way to discourage it.

When operating in built up areas they will carry at least one shotgun per squad, but this is more for breaching hard points i.e. locked doors than for actual fighting, although they can get used for this if necessary and of course as stated, they're good for hunting.

Our shotguns were strictly used for breaching -- set up with pistol grips only, nothing but #9 birdshot or product designed breaching rounds loaded and carried, and shotguns carried on an empty chamber or an expended round still in the chamber at all times except when actively 'gunning a door. (That latter required SOP after a SEAL managed to shoot another SEAL in the clown shoes with a slung shotgun (loaded, safety off) during training -- yet another entry in the highlight reel for the Sleep Eat And Lift boys.)

Shotguns may be in scarce supply. MP's and security units routinely employ the use of shotguns and may issue them as a primary weapon but usually supported by someone else carrying a rifle, carbine or SMG, with both people working/ moving together as a two-man team.

Real world US military the only other people who drew from the Ammo Supply Point I got my bombs and bullets from with shotguns in the inventory were several MP companies. The Sergeant Major who ran the ASP frequently noted (as I was signing for several thousand rounds of #9 birdshot for breaching and 00 buckshot for fighting applications) that he was always amazed that you apparently couldn't pay those MP units to do anything with their issued shotguns at all. Literally most FYs they fired a grand total of zero rounds of shotgun ammo.

Which honestly makes sense -- civilian LE uses shotguns partly because of institutional conservatism and partly for liability concerns (rifle bullets having the external ballistics to accidentally kill someone quite a bit further downrange than shotgun pellets), but are increasingly switching to the M4 or similar patrol carbines. If you've got an M4 you don't really need a shotgun for any LE application (except, here in Alaska, putting down the odd moose or bear).