Hello again,
My Roblox just started working for a brief period before breaking again, and so I am able to give proper feedback on not only the FPS thing but also other aspects of your current system.
(By the way, whenever I say “old <something>” I am referring to default ACS)
The Good
There are a few things that I really like. For one thing, I think the new UI is quite an improvement over the old UI. It looks cleaner and more fitting. Maybe you could make it a bit smaller since it does take up a fair bit of screen space, but other than that it looks good. Second, I really like that your game has modelled height-over-bore with the guns, since the bullets actually come out of the end of the barrel rather than magically coming out from your character’s chest.
The Inaccuracies
There were a few things that are incorrect in terms of realism, so I just thought I’d point them out if you’re interested.
First, the text that says the caliber the gun is chambered for displays incorrect values for some of the guns I tested. You can look this up on your own if you’re interested, so I’ll just give one example, but the AKM is listed as firing 5.56x45mm ammutition when it typically fires 7.62x39mm. There are variants of the AK platform that can fire 556, but this AKM doesn’t look like one of them. The M249 is also listed with the incorrect ammunition.
Another minor nitpick is the belt feeding for the M249. I like that it actually visibly feeds into the gun, but I notice that the gun fires much faster than the belt is actually seen feeding, so maybe you should look into that.
The Bad
Sadly, there are some things that I just are just bad about the game in its current state.
First, there are some bugs. It seems like the UI says the AKM starts in full auto, though I found that sometimes it actually started in semi auto and I had to switch to semi and back to full to get it working (this can be seen in action in the upcoming video recorded at 60fps). Also, after you reload with the M249, the belt no longer feeds. There may be others, I haven’t fully tested everything yet.
Second, I finally was able to do some tests with an FPS unlocker. Here is a clip of the game running at 60 FPS, and here is a clip of the game running with an uncapped FPS (with an FPS counter in the corner). I confirmed that reloads are not affected, but gun sway, ADS speed, and recoil are affected significantly to the point where it makes it difficult and annoying to play.
I know you said that you don’t want to implement a deltaTime solution and are worried it could break something. I would say that you can simply make a backup and take the time to learn how to use it in this context. It would be useful if you want to continue developing (especially if you ever go off of Roblox) to get more comfortable with it.
I know this was a long post, but I try to be as thorough as I can so people can improve their games as much as possible.