Geodus from Hidden Path entertainment has posted a changelog on the Steampowered forums listing the changes that have been made to the CS:S beta and asking for further feedback if required.

Once all feedback has been evaluated these are the changes that will be rolled out into the full game as CS:S continues to get a makeover thanks to the efforts of the competitive community.

The forum post reads:

The beta now incorporates many fixes to weapon bugs that have been implemented over the course of many months and updates. Some of the fixes have necessitated changes to weapon behavior that make them more consistent and more aligned with player expectations. Overall, we think these are good changes for the game, both for competitive and casual players, but before we push these changes into CSS, we'd like to give you an additional opportunity for feedback.

Are there any significant issues in the beta that need to be resolved before this update?

Cumulative weapon updates
-All weapons now have a new accuracy model which fixes many bugs and provides more intuitive weapon behavior
-Weapons now have separate accuracy penalties for jumping, landing, and standing on ladders
-All weapons are now more accurate while crouching
-Accuracy penalties for movement no longer have a discrete threshold, but scale between crouch move and run speed
-All rifles are less accurate while running
-Fixed bug that caused the glock to fire burst rounds on three consecutive tick frames. It now fires burst rounds with a 0.05 cycle time
-Fixed a bug that cause the famas to fire burst rounds on uneven intervals (0.1 and 0.05). It now fires burst rounds with a fixed interval of 0.075.
-Fixed bug for the bolt action sniper rifles that caused their zoom state to incorrectly toggle when holding down fire.
-Fixed bug that would cause the suppressor state on the USP and M4A1 to not be accounted for correctly when the weapons were dropped with the suppressor attached and then picked up.
-Fixed fast suppressor switch exploit
-Decreased range of shotguns, while slightly increasing damage
-Slightly increased damage of m249
-Sniper rifles now zoom faster
-AWP fire animation changed to match 1.5 second cycle time
-Fixed burst fire prediction of FAMAS
-Fixed animation issue with elite dry fire
-Fixed timing of sounds on Glock burst fire
-Weapon spread patterns are no longer square
-Dynamic crosshair now uses actual weapon accuracy, rather than a separate simulation
-Increased run speed for Galil and FAMAS
-Fixed firing of "stale" burst mode bullets on glock and famas.
-Fixed reload animation issue with shotguns under high latency

Other bug fixes
-Re-enabled the ability for max grenades to be set from server convars
-Allow observing other players when mp_fadetoblack is enabled and mp_forcecamera is something other than OBS_ALLOW_NONE
-Pistols no longer continuously spam weapon_fire event when the +attack key is pressed. This has the side effect of no longer allowing the glock to continuously auto-fire in burst mode).
-Weapons no longer continuous cycle the weapon_reload event when the reload key is pressed
-Weapons no longer continuously cycle the empty fire event (and click) when out of ammo and the attack button is held
Scoreboard is now more robust with user modified layout changes
-Added defuser icons to CTs on the scoreboard; these are analagous to the bomb icons for Ts, in that they only are visible for team members and spectators.
-Defuser, bomb, and VIP icons are now colored by team color convar.
-Bomb/defuser icons are no longer shown for members of the opposing team when you are not allowed to spectate them.
-Updated player max speed cap so that it no longer limits players to 240 movement speed
-Allow player max speed to be changed by mods
-Killing friendly players no longer increments the player stat for kills with enemy weapons
-Round no longer ends when timer runs out and mp_ignore_round_win_conditions is set
-Players no longer get weapon donation credit for buying, dropping, and picking up the same weapon
-Fixed crash related to planting C4
-HUD elements for health, armor, timer, and money now have a transparent background for better visibility.

Source: Steampowered Forums