Help needed with custom NIF (private mod)

[21crescendo]

So, this is a private mod, in which I'm using assets from 2 different mod authors. The original NIF is of a CAR 15 rifle reflex sight which I've converted into a Trijicon ACOG

sight using the RU556.

It's not the copying and/or pasting of blocks that I need help with, nor is it placing the right materials path. The sights, the mildot and the red dot et al are aligned properly and work well in game.

The problem arises when I place the backup iron sights from the RU556 on top of the rear stock of the rifle (they don't serve a purpose with the ACOG, just aesthetics). The save game in which I'm using the modded rifle with the custom attachment crashes.

I've troubleshooted it down to the fact that the problem most definitely has to do with the backup iron sights and sights holder blocks. The materials path in both(1

, 2

) blocks is correct (I've double checked); what seems to vary though from the original RU556 is the BSTriShape 'name value'.

I've tried using blank fields, I've tried using name values from the original RU556 nif, I've tried setting some custom names, but they don't work.

I've also loaded up the custom NIF on BodySlide just to check if it works but quite rightly, the application crashes as does the game itself.

What am I doing wrong? Can anyone help me out?