Was trying to go for some high rounds…
And I bought the Thompson off the wall. I had already spun the box and it landed on another thompson. Not paying attention I just swaped the box Thompson for my Kar98k. Then I realised that I only had one gun, that being the Thompson.
After that I was stuck with only one weapon slot. Not really a beneficial glitch just something quirky.
Not sure if this glitch is known already.