0.3.1 is a new mod release you can download from here: https://github.com/BorkBorkGoesTheCode/Odds-N-Ends-mod-prototype/releases
The clip can be fixed by opening the oe_magazine_763x25G.json file with a text editor and changing the 763x25G_clip ammo_type from “762R” to “763x25G”
The itemgroups can be fixed by replacing mags_obscure in oe_item_groups.json with:
{
"type": "item_group",
"id": "mags_obscure",
"items": [
[ "763x25G_clip", 10 ],
[ "type64mag", 10 ],
[ "mp18mag", 10 ],
[ "mp18drum", 10 ],
[ "bizonmag", 10 ]
]
},