Inaccurate Fire Accuracy stat of certain weapons

[Mosuowai]

I have noticed a potential bug that no one seems to have addressed in the forums.  With some weapons, no matter if you hit the target square in the head, or a direct body shot, the fire accuracy stat is almost always 0%. Sometimes it can be a little above that, but I have not been able to work out the mechanics that improves this fire accuracy stat. If you look at the weapons stats of random players, you will notice that with these weapons, the fire accuracy is mostly below 10%, with many in the 1% to 2% range (typical of those who have used those weapons a lot).

The weapons that I have come across with such issues are:

1. Opticor Vandal
2. Phantasma (weirdly, whereas the primary fire counts as a "miss", alt fire counts as a "hit")
3. Shwaak Prism 
4. Angstrum
5. Atomos

I have experimented with using multishot, punch through and other niche mods, both in mission and in the simulacrum. However, they all generate the same result = 0%.

Additionally, I have noticed in some cases, that before max rank, ie when I have equipped and used one of the weapons to increase its rank, the fire accuracy % is quite "normal". I am not 100% sure, but this seems to be reflected with some players who have barely used the weapons, probably just for MR fodder (eg. used 0.1% with just a few hundred kills) but has with a high fire accuracy stat