carmakazi

Generally the rule is you never load a gun before you are ready to use it, and you only load the amount of ammunition you need or are going to shoot.  I only load one round in my shotgun at a time for just clay shooting, despite being a pump action with a 4 round magazine.  For semi-automatic weapons with detachable magazines, it's usually just easier to put a loaded magazine in for practice instead of worrying about the one round.
 
The only time I'd really consider doing it is for self or home defense to get the extra round.  For example, my home defense shotgun in real life is stored with full tube and a round in the chamber, for 7+1 rounds.  A lot of people carry their handguns this way as well.
 
For hunting, a lot of places have limits on how much ammunition your gun may hold.  For most hunts, my shotgun's tube needs to be blocked to hold two rounds, plus one in the chamber for a total of 3.  It must be physically blocked, you can't just load that many shells.  This is strictly enforced by game wardens.
 
Note that some guns, namely a lot of bolt-action rifles with fixed magazines, cannot load an extra round on top of a full magazine.

They're all roughly the same to me, so probably the one that weighs the least, which is likely the M4.  Later on, though, I imagine there are some guns that are going to be more prone to malfunction, and/or need to be cleaned more often.

Made an account just to comment on this.
 
-I bet someone has said it already, but converting your gun between semi-auto and full auto, and presumably between ammo types, eats the weapon mods on the gun.
 
-.30-30 Winchester is erroneously called ".30-30 Springfield," at least on the 20 round box.
 
-I have problems with using cleaning items on some guns.  I can clean my Beretta 92, but not my M1014 or P90.  EDIT: It seems that some guns have the "repaired" value in the little info box and some do not.  So far I am seeing that the Benelli M1014, Glock 20, Walther PPK, Beretta 471 Sawn off, and P90 do not have it.
 
-Shotguns with 00 buck generally seem...lacking in authority.  They seem to do a lot of pushing back, with only an occasional kill, even with decent aiming skill.
 
-I tried using an M4 in semi auto...I couldn't hit anything.  I maybe killed 6 or 7 zombies and expended 100 rounds of ammo.  Is the low accuracy of full auto carrying over to semi-auto?
 
-EDIT: I am of the opinion that the AMT Automag spawns a little too much.  I've found three of them so far, compared to only one example of common pistols like the Glock 17 or SIG P226
 
I'm also looking through your weapon pipeline and I have some concerns with the rarity of a couple items.  I know you have some exotic weapons that pop up extremely rarely, but I think these might be a bit too much.
-Pancor Jackhammer.  There is literally one working model, and it's a tool room prototype, i.e. an ergonomic nightmare.  You need to almost completely disassemble it to reload it.
-The HK UCP never left prototype stage.  Nobody but HK knows for sure, but it's likely I could count the number of prototypes on one hand, and they're all under lock and key at HK.  The MP7 would be reasonable as some US police issue it to SWAT and motorcycle units.
 
Finally, I would like to suggest the Beretta Cx4 as a 9mm, .40, or .45 semi-auto carbine as you see fit.
 
 
I would disagree, because of three things:
1. People don't just buy and keep ammo if they don't have a gun.  People who own ammo will 99% likely own a corresponding gun.
2. Production of ammo will have stopped.
3. People will have expended large amounts of ammunition fighting off zombies and looters in the early days of the outbreak.
 
I think you would have exponentially more guns than ammo the longer the outbreak lasted.
 
Though I will agree that it wouldn't be unreasonable to have zombies that were only able to grab some ammo from somewhere while they were among the living.

Made an account just to comment on this.
 
-I bet someone has said it already, but converting your gun between semi-auto and full auto, and presumably between ammo types, eats the weapon mods on the gun.
 
-.30-30 Winchester is erroneously called ".30-30 Springfield," at least on the 20 round box.
 
-I have problems with using cleaning items on some guns.  I can clean my Beretta 92, but not my M1014 or P90.  EDIT: It seems that some guns have the "repaired" value in the little info box and some do not.  So far I am seeing that the Benelli M1014, Glock 20, Walther PPK, Beretta 471 Sawn off, and P90 do not have it.
 
-Shotguns with 00 buck generally seem...lacking in authority.  They seem to do a lot of pushing back, with only an occasional kill, even with decent aiming skill.
 
-I tried using an M4 in semi auto...I couldn't hit anything.  I maybe killed 6 or 7 zombies and expended 100 rounds of ammo.  Is the low accuracy of full auto carrying over to semi-auto?
 
-EDIT: I am of the opinion that the AMT Automag spawns a little too much.  I've found three of them so far, compared to only one example of common pistols like the Glock 17 or SIG P226
 
I'm also looking through your weapon pipeline and I have some concerns with the rarity of a couple items.  I know you have some exotic weapons that pop up extremely rarely, but I think these might be a bit too much.
-Pancor Jackhammer.  There is literally one working model, and it's a tool room prototype, i.e. an ergonomic nightmare.  You need to almost completely disassemble it to reload it.
-The HK UCP never left prototype stage.  Nobody but HK knows for sure, but it's likely I could count the number of prototypes on one hand, and they're all under lock and key at HK.  The MP7 would be reasonable as some US police issue it to SWAT and motorcycle units.
 
Finally, I would like to suggest the Beretta Cx4 as a 9mm, .40, or .45 semi-auto carbine as you see fit.
 
 
I would disagree, because of three things:
1. People don't just buy and keep ammo if they don't have a gun.  People who own ammo will 99% likely own a corresponding gun.
2. Production of ammo will have stopped.
3. People will have expended large amounts of ammunition fighting off zombies and looters in the early days of the outbreak.
 
I think you would have exponentially more guns than ammo the longer the outbreak lasted.
 
Though I will agree that it wouldn't be unreasonable to have zombies that were only able to grab some ammo from somewhere while they were among the living.