I have been experiencing the same issue. It seems when the AI fire at me, my systems locks up. I have watched the CPU and GPU and nothing major except the gpu load drops to 0% on lock.
his problem seems to have started after the recent update.

I have also saw this in my game as well. As soon as I'm hit the game stops responding for a short time. I drove a vehicle down into an area with several enemy AI and the game became unplayable for more than 45 seconds. It took a while after I respawned even for the game to smooth out again!

I agree that this only started happening after the latest patch.

I found a way to play the game without this happening - But it's not the best solution as it limits the amount of servers you can play on. But this fixed it for me sorta..

1. Open Steam and go to your game library
2. Right click on ArmA 3 Alpha, click Properties
3. Click on the BETAS tab
4. Click on the drop down menu, choose development - Development Build

Only problem now is that I can't remove development build now. What this does is change the type of servers you play on to DEV servers. If someone finds a fix on how to switch back, let me know.

UPDATE ON THE DEVELOPER BUILD:

My mistake, I was unable to switch back because the game was already running lol. So you can switch back. My mistake :P

Once an issue is fixed in the developer build, it is considered resolved. I guess this can be closed?

It's still not completely resolved. There are still some instances where the game can crash when taking damage. But it doesn't happen so much as compared to when developer build is off

I switched back over to regular mode (with developer build off) and the same thing happens - I get shot or take damage and the game crashes. So only while in developer mode it doesn't crash when I take damage

UPDATE:

Even while in developer mode, I now get the constant crashing when taking damage. Multiplayer is now unplayable for me.

I've experienced it while playing offline as well. In one mission so far, community made "Black Sheep" coop version (for some reason I've chosen to play alone a coop mission, with AI as teammates, despite having a dedicated single player version). Everytime I got hit, the screen froze for a second or two, no matter if killed or wounded only. After the freeze, the game was running normally. It hadn't happened in other missions so far (including coops played offline as single). Maybe it's some missions scripting specific? I have Arma 3 Alpha (no dev build).

I removed the Colt M4 pack and it resolved the freezing while taking damage or under fire issue for me.

@bigk9359, please attach the RPT and dump files after the next crash/freeze, as per the how-to-guide. (http://feedback.arma3.com/how-to-user.html.html)

I've been busy with school since it's finals week. I will once I'm able.

I do not have this issue, mine works just fine...

what addons are you using.

I'm back. And I tried playing the game without the Dev build on. The problem is now fixed after an update.

Thanks.