You are having a lovely day playing New Vegas when you get this shiny new weapon that you want to make one of your main guns. Unfortunately, the minute you hit one of your number keys while in the PipBoy it's CTD time. What do you do?

Well, I've tried this solution on two separate installs and on multiple save files that were experiencing the glitch. This corrected it in every case:

1) Find a flat spot where you don't think things are going to fall through the floor.
2) Go into your PipBoy and drop every single weapon in your inventory. ALL OF THEM. Every single one. Don't put them in a box or anything else. DROP EM'!
3) Anything else you may have assigned to a hotkey (stimpack, drugs, water, food, etc.) needs to be dropped as well. Again...do not put them into a container. DROP EM'!
4) Now close the PipBoy and start picking everything up. Pick up every item before you go back in to the PipBoy.
5) Open the PipBoy to the weapons tab. Odds are you are going to see quite a few of the weapons missing even though you just picked them up. DON'T PANIC!
6) Close the PipBoy again, then go back in. You should see all of your weapons again.
7) Start assigning hotkeys again. :foodndrink:

As always, ymmv. I've got my fingers crossed for you though. :goodjob:

This worked for my system as well. Thanks! I'll pass the info along to the other threads.

Nice workaround...

Thank you for this workaround, this solved the problem for me !

This is to do with the same bug as multipule caravan cards is it not, I think the issue is exact copies of items and takes place in weapons of exact condition as well.
I have seen it crash when modding a weapon when there is a copy of it hidden underneath the one you're modding, and combined with the glitch where the inventory does not update the first time apon entering.

Thanks for the this great hint, another way is to clear out weapon / clothes stocks often, use a container to place the weapons you wish to keep.
Then go to a merchant and sell all items, as some don't update their #'s, as 3 laser rifles did so with me.
It was not untill I moved one out that I found I was carring two more causing crashes when I modded.