To Reproduce
Steps to reproduce the crash:

1. shoot any galacticraft/extra planets mob, npc or otherwise
2. while shooting game most of the time crash, whether it be before the mob fully dies or immediately afterwords
3. sometimes shooting will not result in crashing, but this almost never happens

Screenshots
If applicable, add screenshots to help explain your problem.

Versions (please complete the following information):

• Forge: forge-14.23.5.2808
• Flan's Mod: Flan.s.Mod-1.12.2-5.6

Additional context
Add any other context about the problem here.
randomly occurs while shooting, sometimes when they die or randomly during when they are shot, vehicle guns/turrets do not have this issue
Add a link to a gist of the crash.
https://gist.github.com/paradoxmeem/0fc0346ea03730946326568268d4842b

I wasn't able to reproduce this myself with the same versions of Forge, Flan's Mod and Galacticraft.
It looks like the exception is being thrown while running the Galacticraft BasicBlock code, you may want to go ask them about this.

Closing for now.

Just found this issue (micdoodle8/Galacticraft#3530)
I'll look further into this.

thanks, these are both great mods and having them atleast working together would be a dream.

I still wasn't able to cause the crash myself but took a stab at fixing it.
Could you try the version included in the attached zip and let me know if the problem persists, please?
Flan's Mod-1.12.2-5.6.jar.zip

i will try, but i wont have access to a computer for ~30 min

so sorry, accidentally fell asleep. issue keeps occurring, even with the mods only by themselves. i should've put the crash report here earlier, sorry
The game crashed whilst unexpected error
Error: java.lang.ArrayIndexOutOfBoundsException: -3

@paradoxmeem What gun are you shooting? What type of ammo? What world are you in? What block is the bullet hitting?

this occurs with every gun so far that I've tested, which is an m1014 or so, spas 12 and an mp5. theirs probably a few others I've forgotten. normal version of the ammo for every gun mentioned.
these all happen in different/new worlds
bullet normally hits person then immediately crashes, it doesn't matter what it hits but the blocks are moon surface rock and tin decoration block normally

tested with desert eagle in a completely new pack, issue persists

https://gist.github.com/paradoxmeem/e7ad4dcb9ada803bf40674a15e6ab044

I've still been unable to reproduce this crash in my local single-player and so am unsure how to fix it. A simple fix for the crash on Galacticraft's side could be to add some bounds checking.

If you could update the original crash paste link with one containing the crash log from when you only had Galacticraft and Flan's Mod installed, that may help in future.

i can do that, but not at this moment. sorry.

Was going to make a similar issue, but for me I was shooting a ordinary vanilla skeleton and I was using an Olympia, although there were Galacticraft ore on screen. This is with flans 5.6 and the most recent stable version of Galacticraft.
These are the crash report files; it happened twice for me. I'm not sure how to upload them to GitHub.
crash-2019-07-25_14.39.52-client.txt
crash-2019-07-27_11.31.22-client.txt