I posted the Accurate one in a similar thread and the spark behind the full auto fix, but I feel that these changes help to improve realism, tactical in game decisions and make it less mindless for choices.

Accurate:

Accurate Weapons grant an additional bonus of +10 to the firer’s Ballistic Skill when used with an Aim Action, this is in addition to the bonus granted from Aiming.

When ?ring a single shot from a single Basic Weapon with the Accurate quality that is benefiting from the ½ Action Aim gains a one extra d10 of damage if you have two or more degrees of success. If you use the Full Action aim, you may have a maximum of two extra d10. In addition, you must use the called shot action to gain this bonus.

Full Auto:

Full Action shooting attacks grant +0 BS when being used, you still get +1 hit for every DoS. Suppressing Fire is not changed. Fixed guns (i.e. pintle, bolted down, emplacement, etc.) gain a +20 to BS and and braced weapons still gain +10 to BS.

Bracing:

Bracing a weapon takes a Half Action and once braced the firer cannot move without losing the benefits of being braced. They can however traverse their weapon depending on the kind of bracing they have (i.e. a windowsill, sandbag or pile of rubble would allow a 45 degree traverse as would simply lying on the ground, a bipod would allow a 90 degrees traverse and a tripod 180 degrees, while a pintle mounting could be turned in any direction). In addition, as long as the weapon is properly braced you gain +10 to BS, this applies to most guns and fire modes (with GM discretion of course)

Not sure how to work Bulging Biceps into this, as firing a heavy weapon unbraced has real penalties now (as it should of course), but having greater Strength helps them deal with recoil better.

Some interesting work. Personally, however, I like a different option for FA and SA that I saw a while back on these forums. That was to make SA give an extra hit for every degree of success to a maximum of the ROF as well and to make FA double the requisite range modifier. That made fully automatic weapons somewhat realistically devastating at point blank range but also realistically useless at long ranges.

However, I really like your bracing rules. I've always been annoyed that bipods can be added to basic weapons yet the bracing action is useless in (almost) all cases with basic class weapon rules.

there is one problem that i can see with this - it makes accurate weapons worse at what they're meant for - punching through enemies with really high soak - for an example:

SPOILER

Miss Book from Dead Cities has effectively 18 TB (60T+UnTx3) and a pulse field reduces damage by 10 from ranged attacks and isn't effected by penetration and regeneration (2d5+5) - so effectively you have to do 36+ dmg (assuming your the only one attacking her) to have any effect and with your rules most accurate weapons wouldn't be able to touch her unless they only attacked 2 out of every 3 turns (full aim, half shoot, full aim, half shoot) and if they're shot between turns they just won't be able to damage her at all - and if they wanted to do the half action aim the max damage they could do with any gun is 2 after soak (angelus bolt carbine) which would likely be healed as there's an 80% chance that she would be healed for 7-15 wounds

what would you suggest - that the sniper with little str (so bulging biceps is impossible) uses a heavy weapon choice of a full auto gun they can't use of a missile launcher loaded with krak missiles that they also can't use or of course the assassin trained solely in gun skills could always go into melee and hope they do more than 26 dmg with the Omnisian Axe (which they stole from a tech priest) (about 5% chance of doing enough dmg) or hope that they're a latent psyker with high willpower and use a force weapon