So a few weeks ago, my DM gave me what could only be described as a laser gun. It's supposed to deal 1d8+prof Necrotic damage. I only remembered it recently and so I decided to Homebrew the item onto my character sheet (My DM doesn't use this site so that's why he didn't make it himself). I decided to copy the Laser Pistol and try and edit it. I added the description my DM told me, the charges it's supposed to have and then I went to Modifiers, the only section that mentions Damage (Excluding Basic Information which doesn't have an option for changing damage). I put in the 1d8 necrotic and then see if it worked by giving it to my character. Nope, the gun apparently does 3d6 radiant + 1d8 necrotic. I've been trying to figure this out for ages, I even went to the forums to see if anyone else had this problem as well as the Tutorial and FAQ, but that only talked about armour for magic Items. Please help me with this, I'm getting quite frustrated

 By now you may have received an answer to this question by someone. If not, I believe that in this case you can either delete the modifier you made and add in the following information or select edit said modifier.

Once editing, select modifier type and scroll down until you find Replace Damage Type. Then select necrotic in the modifier subtype, and then set the dice amount to what you need. Also make sure you select proficiency bonus under the additional bonus type, and it should be good to go as 1d8+ prof. And as always test to make sure. 

Oh my god, life saver

Glad to be of assistance, especially if it works. Also checking out some of the Builds Character videos on the D&D Beyond's twitch or youtube channels can use useful. I know that there was an episode that tackled making magic items on D&D Beyond.

This doesn't work though. The dice amount doesn't change.

Quote from Insaneflame2 >>

This doesn't work though. The dice amount doesn't change.

 We can't change the damage die of the weapon roll as of this time, it's tied to the damage die of the base weapon. What are you trying to do?

Items & Equipment FAQ #1: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq).

Quote from naruhoodie >>

Quote from Insaneflame2 >>

This doesn't work though. The dice amount doesn't change.

 We can't change the damage die of the weapon roll as of this time, it's tied to the damage die of the base weapon. What are you trying to do?

I'm trying to reply to someone to explain that their solution to the problem doesn't work. They said to use Replace Damage Type to change the damage dice.

I didn't want other people to waste their time attempting that solution to a problem currently without a solution

Quote from Insaneflame2 >>

Quote from naruhoodie >>

Quote from Insaneflame2 >>

This doesn't work though. The dice amount doesn't change.

 We can't change the damage die of the weapon roll as of this time, it's tied to the damage die of the base weapon. What are you trying to do?

 

I'm trying to reply to someone to explain that their solution to the problem doesn't work. They said to use Replace Damage Type to change the damage dice.

I didn't want other people to waste their time attempting that solution to a problem currently without a solution

 You're correct that the Die Count & Die Type fields don't work for the modifier Replace Damage Type, but it's still viable for changing the type of base damage done by the weapon.

Quote from naruhoodie >>

Quote from Insaneflame2 >>

Quote from naruhoodie >>

Quote from Insaneflame2 >>

This doesn't work though. The dice amount doesn't change.

 We can't change the damage die of the weapon roll as of this time, it's tied to the damage die of the base weapon. What are you trying to do?

 

I'm trying to reply to someone to explain that their solution to the problem doesn't work. They said to use Replace Damage Type to change the damage dice.

I didn't want other people to waste their time attempting that solution to a problem currently without a solution

 You're correct that the Die Count & Die Type fields don't work for the modifier Replace Damage Type, but it's still viable for changing the type of base damage done by the weapon.

 Yes, but they said it did work for Die Count and Type. I said it didn't. I fail to see the miscommunication here.

I asked this question a year ago, I'm surprised people are still arguing about it

*shrug*

So fun tidbit while you can't change the bace damage dice as a workaround you can add addition damage dice even of the same type granted it rolls them separately so it doesn't look as cool but I meeeeeeean it does the trick 

IE: Check out my rendition of Pythors Mythril Greataxe from AotDL

 To Achieve This Simple Add a Modifier
Damage - Slashing/Piercing/Bludgeoning/Whatever

Add However Much Damage Dice you Need and of whatever type

Quote from Spawn3601 >>

So fun tidbit while you can't change the bace damage dice as a workaround you can add addition damage dice even of the same type granted it rolls them separately so it doesn't look as cool but I meeeeeeean it does the trick 

IE: Check out my rendition of Pythors Mythril Greataxe from AotDL

 To Achieve This Simple Add a Modifier
Damage - Slashing/Piercing/Bludgeoning/Whatever

Add However Much Damage Dice you Need and of whatever type

 
It doesn’t roll them separately, it doesn’t roll them at all unless you are using the Beyond20 extension.

Just to add so that people understand...
Beyond20 is an extension on the chrome store that makes d&d beyond roling easier by literally addding whats missing on DnDBeyond. like the cleric life subclass added to healing spells... it also adds and rolls any additionnal damage dice you add to a weapon including as an exemple the flame-tongue weapons. if you were to disable the extension. you would notice that the flame-tongue weapon do not roll additionnal dice anymore. thats because DnDBeyond did not add any of those aditionnal rolls to their engine. and thus DnDBeyond doesn't do additionnal damage dice from anything.

so in short, Beyond20 extension adds functionnality to your dice roller on DnDBeyond. without it, those functionnality are lost !

i would just change the weapon type if you want specific damage

Quote from Reconzebra >>

i would just change the weapon type if you want specific damage

That is exactly how to do it, I explain how to go about doing that in this thread. Referring to OP's post from 2 years ago, They would want to build the weapon off a Palm Pistol (Exandria) which does 1d8 piercing damage and make the appropriate changes.

Though the OP also said it's 1d8+proficiency bonus. I am unaware of a way to change the damage from 1d8+modifier to 1d8+proficiency bonus

In the case I am looking for was a way to do a Brown Bear Bite attack (for Druid case) and statically set the dice and bonus modifiers.  Still playing around with this right now as i have noticed creating a custom action does not work as you cannot set a static hit bonus but can for damage.

You can’t set a static attack bonus on a weapon either. Try creating a feat and adding an Action to it. Then you can add the feat directly to your character sheet and the Action will populate.

Quote from bitflingr >>

In the case I am looking for was a way to do a Brown Bear Bite attack (for Druid case) and statically set the dice and bonus modifiers.  Still playing around with this right now as i have noticed creating a custom action does not work as you cannot set a static hit bonus but can for damage.

Give this a read through.