If you want to have a low chance of a mishap and/or spend less ammo, you don't go full auto, you use short controlled bursts, in this game that is represented by using a ROF of 1. Just because you can use a lot of ROF, you don't have to.
Yes, that is an option, but the way the game is set up you have a 25% chance of mishap WHENEVER you use 4 Ammo dice. That's basically saying that a pintle mounted MG get messed up a quarter of the time its used in combat. That .50 cal on the Abrams? After suppressing the enemy for a bit, it's definitley going to need to be replaced/repaired/unjammed. Once again, this is a spot where the mechanics start creating disincentives for specific actions due to flukes of the system, not because of any kind of modeled reality, verisimilitude, or reason... it's just a wrinkle with no real reason.
Making CUF also play a role in trigger discipline/ammo use makes that stat even more useful and I think adds to the verisimilitude of well trained military folk doing a better job of "counting shots" than untrained civvies.
Adding to what Cheep said:
What we're seeing is a potentially unrealistic ammo expenditure and breakdown rate for allegedly "trained" shooters. With each potential mishap, the rating drops on your weapon, and it isn't inconceivable that a run of bad dice could drive a spec ops characters weapon from A to D in 3 bursts...and drain 3 magazines...something that statistically should never happen...
I get that it's only a 12% fail rate guaranteed with 4 ammo dice (based on ammo dice alone), and I get that you use short, controlled bursts - I was a Marine. I've been through the Police Academy. I've carried and/or qualified with many of the US weapons listed. And in my experience, your ammo burn rates and failure rates are too high.
I love the idea of weapon quality ratings and wear and tear degrading weapons....great add...but a well maintained weapon shouldn't have a really high fail rate.
When the M16 was introduced, it had a malfunction rate of 2 per 1000 rounds...by the year 2000, the A2's were common, they had a 1% malfunction rate. A weapon with an "A" reliability rating shouldn't be misfiring and degrading that quickly.
And I think the ammo expenditure needs tweaking.
A bolt action sniper rifle has a RoF of one...I am not likely to fire 6 shots in a 5-10 second window AND hit multiple targets while doing so. Snipers by definition don't use "spray and pray"...but the Ammo Spent mechanic doesn't differentiate. There is no option for "Short, controlled bursts" because the Ammo dice may fire 5 rounds on a single die...or on 3 dice...MY control is almost entirely removed in favor of random die rolls.
My group will be test driving this today - We'll see...