Reasons :

I developped a tool for modders that allows them to correctly display their weapons in the new magazine menu in A21.
I first developped it for Vanilla Firearms Extended (will be uploading an update in the next day or so, had some issues to handle), and also to help Izayo display his shotguns (awesome pack you should try it) into the menu, because he did not succeed in making the menu display his weapons. So I wanted to be of help for him. I proposed him this solution just before posting ths framework.
I decided to upload it now because I figured people who love to make weapons packs would be interested in displaying those correctly.
You have to test all Izayo's mods at least once, because they all are really cool and gorgeous looking.

Remark :

Only modders would have to use this. Other players would download it with other modders' files as if they use it, it will be included in their files (or at least that's what I hope, downloading it from this page should work in case of need). I will include it in VFE for example. If Izayo use it, it will be included in his files. If you have multiple weapon packs and your OS asks you if you want to replace, say yes or not, it does not matter as long as you have one in your game mod folder.

This mod will do nothing on its own, visually speaking, it is only required if and only if the modders want to use it and follow the instructions below.

New files :
- Patches for Izayo's firearms to work with my framework, if you use Vanilla Firearms Extended and/or if you are bothered with not seeing the displaying of next unlocking in magazine menu. When you extract the patches, take the progression.xml file you find inside it, and put in it the corresponding Izayo weapons pack, and select Yes to replace it. Then it will work as intended.
- Patch to use Izayo's 5.56mm guns with Vanilla Firearms Extended same caliber. Uploaded here for convenience and example.
- Patch to use Izayo's shotguns ammo in Vanilla guns and VFE + Vanilla guns (choose one).
- All-in-One patch for Izayo and VFE that contains all changes + Vanilla shotguns using Izayo's shotgun ammo.

Technical :

The solution is awefully easy in fact. Technically, the game does not allow for more than 1 item to be displayed at a time. Unless we use of the food crafting method : A display entry which contains unlock entries. So I had to delete the display entry of each of the 4 gun types, and create a new one for each that is of the complex type. Just see pictures for more visually appealing info.

Every modder who master XML out there, and some of the faster spirits here would have figured this without problem. The main goal of my framework is to centralize every gun pack into one and only one display menu, without cluttering it as Izayo did on the Version 2 of his gun packs.
And Izayo is super busy, and will be even more in the future, so I wanted to help him. So here's the new Duriel mega useful tool. I hope it will be of help for every one here.

How to use this framework ?

Simple as any other adding patch. I cannot put colour on the code apparently so I'll try to explain as best as I can. See the second image for example code.

First, display-entry :
<append xpath="progression/crafting_skills/crafting_skill[@name='craftingHandguns']/display_entry[2]/unlock_entry/@item">,YOUR-GUN-GOES-HERE,YOUR-OTHER-GUN-TOO</append>

- Don't forget the COMA here, if no coma is put at the beginning, and between each entry, the patch won't be loaded.
- The craftingHandguns can be replaced with rifles, shotguns, or machineguns following the need.
- The number of display-entry[2] can be 1 2 3 or 4 (or 5 for handguns).
- The unlock-entry is new and is now MANDATORY for the patch to work.

Second, recipe tag unlocked :
<append xpath="progression/crafting_skills/crafting_skill[@name='craftingHandguns']/effect_group/passive_effect[@level='11,100']/@tags">,YOUR-GUN-GOES-HERE,YOUR-OTHER-GUN-TOO</append>

- The level of the unlocking can be anything in the vanilla progression file, just look at it.

Third, crafting tier :
<append xpath="progression/crafting_skills/crafting_skill[@name='craftingHandguns']/effect_group/passive_effect[7]/@tags">,YOUR-GUN-GOES-HERE,YOUR-OTHER-GUN-TOO</append>

- The passive_effect number would start at 5 and end at 8 for all guns, save for handguns, which have 5 tiers, so it starts at 6 and end at 10.
- The first one (5 or 6 for handguns) ould be the Tier 0, so usually you won't be using it.
- You can also use the real level definition, which would be "1,3,5,7,10" at first and then each subsequent tier would start one level after the last one of the precedent tier.

You can put as many guns as you wish, but know that their are only 14 squares to display your weapons for each tier, and only 5 tiers can be displayed. Without a UI patching being involved at least.

Note :
This framework can be extended upon. For example if you are a melee weapon modder who wants to include new blades, blunt weapons or even electrical/mechanical weapons such as new turrets and batons. So for that matter changing the name to the related perk should be easy. And is completely free to do by yourself. Or asking me if I can I will gladly do it to help anyone who needs help in doing the extension.

Any question on this matter can be posted in the comment section, I will answer with my best to help everybody.

I don't see the Mirror I put in the file details so here's the link on MediaFire for the modders that aren't logged in or have no account on Nexus.

Crediting me for this would be appreciated but you can use it without credit. Throwing the link back here would also be appreciated but not mandatory either.