Is a +1 chain shirt strictly inferior to a nonmagical breastplate?

Question

My character really likes chain shirts. He much prefers them to other armor, such as a breastplate.

I thought maybe I could make up for his tastes with a piece of magical armor, since usually magic items are considered stronger than mundane ones. But I'm realising that it's still not quite as good. There are two benefits to mundane armor that I can find, and no such relative benefits to magic armor (besides the AC bonus):

1. Magic items can be suppressed by the antimagic field spell, and there seems to be no way to make non-magical armor not work that wouldn't also work on magic armor. With mundane weapons some creatures will be able to resist, so magic on weapons is great. Not so with magical armor, as far as I know.

2. A Forge Cleric can use their Blessing of the Forge ability on nonmagical armor, but can't use it on magical armor:

   At 1st level, you gain the ability to imbue magic into a weapon or armor. At the end of a long rest, you can touch one nonmagical object that is a suit of armor or a simple or martial weapon. Until the end of your next long rest or until you die, the object becomes a magic item, granting a +1 bonus to AC if it’s armor or a +1 bonus to attack and damage rolls if it’s a weapon.

Is there anything a +1 chain shirt has that a mundane breastplate doesn't have?

Answer 1

There is a difference between a +1 chain shirt and a breastplate beyond the AC properties. Whether or not it's "strictly better" will be heavily dependent on the campaign, specific environment and party makeup

Depending on the situation and your campaign they have pros and cons, so neither is "strictly worse" than the other. I've put together a list of potential differences based on the rules text associated with magic items and the specific pieces of armor:

• Magic Items are more durable due to their resistance to all damage. As a result if your DM is allowing for armor and weapons to become broken, magic items should fare better. Magic items will also be more likely to be usable if taken from a monsters body than the equivalent mundane armor.

  Most magic items, other than potions and scrolls, have resistance to all damage.

• Breastplates are fitted to the user while Chain Shirts are not. As a result, scavenging a chain shirt from an enemy is easier than doing the same with a breastplate. Similarly, it is much easier to swap a chain shirt between party members than it is a fitted breastplate.

  This armor consists of a fitted metal chest piece worn with supple leather. [...]

• Chain Shirts are more discrete and easier to hide than a Breastplate. This has potential roleplay implications (eg it's harder to justify turning up for a dinner in a breastplate, compared to a chain shirt hidden under your clothes).

  [...] a chain shirt is worn between layers of clothing or leather. This armor [...] allows the sound of the rings rubbing against one another to be muffled by outer layers.

• The attacks of monsters like Oozes specifically damage nonmagical armor, so a +1 chain shirt is immune to these effects. Example from the Black Pudding:

  In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative -1 penalty to the AC it offers. The armor is destroyed if the penalty reduces it's AC to 10.

• As a magic set of armor, the +1 chain shirt will be excluded from specific game effects that improve the armor, like the ones you have mentioned in your question. Not all parties will have access to these features however.
• If your DM is playing with the optional lingering injuries rules they may decide losing an arm or a hand is easier when wearing a breastplate than a chain shirt as the breastplate explicitly leaves the extremities uncovered.

  [...] Although it leaves the legs and arms relatively unprotected, this armor provides good protection for the wearer's vital organs [...]

Answer 2

There are differences between a magical and a non-magical object

(other than the obvious one about a magical object being a priceless artifact)

Magical objects are much more resilient to damage than normal ones. This has two potential effects in the game:

1. Magic items have resistance to all damage (DMG pg. 141)

2. Most monsters and spells can't damage magic items. For example, Rust Monsters and Oozes cannot dissolve magical armor.

How often this comes up depends on the campaign, but it's good to be aware of this.

Answer 3

The +1 chain shirt is more durable than a breastplate, but this is a relatively very small difference between them. Consider, for example, that you could have a +1 breastplate nearly as easily as a +1 chain shirt and this becomes quite clear—now the breastplate is again strictly superior.

However, all is not lost—any reasonable DM should be happy to let you describe your character’s visual appearance more-or-less any way you like. If it’s a special, custom item that makes that happen—a superior +1 chain shirt that despite appearances functions as a +1 breastplate, then that’s fine. Or just handwave the issue away. The point remains that beyond the very earliest levels, characters are expected to be wearing whatever armor gives them the best AC, or the best AC without disadvantage on Stealth if that’s important to them. The game is designed for fairly tight AC ranges, and not doing that causes problems. The difference in cost and availability between a chain shirt and a breastplate ceases to matter much at all once you’ve leveled up once or twice. You should neither be “punished” for meeting that numerical expectation (by wearing an armor that does’t jibe with your preferences for the character), or punished for having your character have a certain visual appearance (by having less AC than you should have by all rights). Neither of those results is good for the game—both of them are bad for the game.

Thus, a good DM fixes the problem. That’s why you have a living, breathing, thinking DM in the first place, and not a computer.

Answer 4

Yes, it has

Magic armor is more durable than mundane.

Most magic items are objects of extraordinary craftsmanship. Thanks to a combination of careful crafting and magical reinforcement, a magic item is at least as durable as a nonmagical item of its kind. Most magic items, other than potions and scrolls, have resistance to all damage. Artifacts are practically indestructible, requiring extraordinary measures to destroy.

Answer 5

I am not 100% sure about the official rules on this, but there are at least some groups that uses disadvantages or even restrictions regarding sleeping in some types of armor. So if you get woken up in the middle of the night, you will have to fight unarmed or perhaps be considered not getting a full nights rest while sleeping with it on.

Since I can't find the official rules regarding this, it really comes down to whether or not your group has any of these restrictions put in place. For example, if your group thinks sleeping in a chain shirt is ok, but not breastplate. Then that's certainly one benefit to chain shirts, even if it might not happen a lot.

EDIT: As noted by illustro, I was a bit confused by the type of armor you were asking about. To clarify though, there might be house rules that treats sleeping in different armors differently. There are as far as I can tell no official ruling or differences on it.