I'll fix the missing year of manufacture, that was a mistake on my part, and the person I asked to look over these before seems to have missed that as well.
On the muzzle velocity, compared to the LASR, these make a lot more sense for how it is made; the coils are considerably larger and longer than those found in the LASR, yet the LASR seems to still be capable of 6,000 M/S, granted with a smaller round.
The muzzle flash isn't caused by the propellant; it's actually caused by the air being ignited by the friction caused by a round moving at several thousand meters per second. It's a very small muzzle flash, and I will admit that it's mostly included for style, but I think that it is a reasonable phenomena to occur.
On the weight of the rounds- I will admit that I have no idea how much Uranium weighs, and was simply guessing. I can change the weights to make more sense, if you'd like me to.
The ASGR gets a greater muzzle velocity by trading cycle rate for power; that's why the SSGR has a much higher rate of fire than the ASGR, it trades power for cycle rate.