All guns will be more accurate and lower recoil.
All guns will have penetration effect, see the pics.

Handgun:
All handguns increase repelling ability and have penetrating power, some pistols have mute effect.
SG-09R increases the initial power, the base crit rate is 20%.
Punisher enhances exclusive power  x1.5, base crit rate is 20%.
Red9 increases the base damage, exclusive power  x2.5, always has a crit effect, but no longer increase the damage.
Blacktail magazine capacity increased, exclusive power  x2.5, base crit rate 20%.
Matilda exclusive Modification is Unlimited Bullets.
Sentinel Nine has slightly increased power, and the base crit rate is 20%.
Improve all Handguns projectile distance, You can shoot the Church Bell in the village battle.

Shotgun:
All shotguns have more focused ballistics and 25% more power.
All shotguns have increased clip capacity and increased reload efficiency.

Machine gun:
TMP exclusive power becomes 2.5 times.
The power of LE5 is increased, and the power of the exclusive modification becomes 1.5 times.

Rifle:
SR M1903:  exclusive power x2.5.
Stingray improves firing efficiency, and exclusive power x1.5.
Rifles have mute effect, exclude CQBR.

Magnum:
Broken Butterfly: exclusive  power x1.75.
Killer7 has a base crit rate of 20%.
Handcannon improves reload efficiency.

Knife:
All knives become infinitely durable after the exclusive modification And compensate the damage.
Attack speed is constant at 1.4.
Improves the knockback ability of the knife.
Increased attack range x2.

BoltThrower: 
Improve BoltThrower projectile to fly faster, straightly.
Exclusive modification is ammo capacity x20.
Critical rate is 100% now.


Some References:
Perfect accuracy
Tighter Shotgun Spread
More Penetration