I've made a few weapons (Beretta 92FS, Rheinmetall MG3, HK G36, FN P90, Kar 98k) for the mod that I'm using in my own games.
I simply added them to the CE Guns submod. Really easy to do. Just create a new entry (copy from existing gun then modify) in the Weapons_CE_Guns file then create the textures and throw them in the texture folder. To create the texture just find an image of the gun you want, scale it down then create a black 1 pixel border around it (in photoshop this is done with a black glow under layer blending).
Here's the textures that I've made
Beretta 92FS

G36

P90

K98k

MG3 uses the MG60 texture.
And the code I use (make sure to name the textures properly corresponding to the code if you're going to use this)
EDIT: Also, note that rate of fire is determined by ticksBetweenBurstShots variable and is logarithmic in scaling. Example of input and rounds per minute displayed in the game.
Example table:
1 3600
2 1800
3 1200
4 900
5 720
6 600
7 514
8 450
9 400
For the MG3 I use 3, which gives me 1200 RPM while for the G36 I use 5 which gives me 720 RPM.
I simply added them to the CE Guns submod. Really easy to do. Just create a new entry (copy from existing gun then modify) in the Weapons_CE_Guns file then create the textures and throw them in the texture folder. To create the texture just find an image of the gun you want, scale it down then create a black 1 pixel border around it (in photoshop this is done with a black glow under layer blending).
Here's the textures that I've made
Beretta 92FS

G36

P90

K98k

MG3 uses the MG60 texture.
And the code I use (make sure to name the textures properly corresponding to the code if you're going to use this)
Code Select
<!-- ==================== G36 ==================== -->
<ThingDef ParentName="BaseHumanMakeableGun">
<defName>CE_Gun_GThirtySix</defName>
<label>G36</label>
<description>Ancient military assault rifle.</description>
<graphicData>
<texPath>Things/Weapons/G36</texPath>
<graphicClass>Graphic_Single</graphicClass>
</graphicData>
<soundInteract>InteractRifle</soundInteract>
<statBases>
<WorkToMake>28000</WorkToMake>
<SightsEfficiency>1</SightsEfficiency>
<ShotSpread>0.07</ShotSpread>
<SwayFactor>1.28</SwayFactor>
<Bulk>7.00</Bulk>
<Mass>3.50</Mass>
<RangedWeapon_Cooldown>0.37</RangedWeapon_Cooldown>
</statBases>
<costList>
<Steel>50</Steel>
<Component>5</Component>
</costList>
<verbs>
<li Class="CombatExtended.VerbPropertiesCE">
<recoilAmount>1.27</recoilAmount>
<verbClass>CombatExtended.Verb_ShootCE</verbClass>
<hasStandardCommand>true</hasStandardCommand>
<defaultProjectile>Bullet_556x45mmNATO_FMJ</defaultProjectile>
<burstShotCount>6</burstShotCount>
<ticksBetweenBurstShots>5</ticksBetweenBurstShots>
<warmupTime>1.1</warmupTime>
<range>50</range>
<soundCast>ShotAssaultRifle</soundCast>
<soundCastTail>GunTail_Medium</soundCastTail>
<muzzleFlashScale>9</muzzleFlashScale>
</li>
</verbs>
<comps>
<li Class="CombatExtended.CompProperties_AmmoUser">
<magazineSize>30</magazineSize>
<reloadTime>3.5</reloadTime>
<ammoSet>AmmoSet_556x45mmNATO</ammoSet>
</li>
<li Class="CombatExtended.CompProperties_FireModes">
<aiUseBurstMode>TRUE</aiUseBurstMode>
<aiAimMode>AimedShot</aiAimMode>
<aimedBurstShotCount>3</aimedBurstShotCount>
</li>
</comps>
<recipeMaker>
<researchPrerequisite>PrecisionRifling</researchPrerequisite>
</recipeMaker>
<tools>
<li Class="CombatExtended.ToolCE">
<label>stock</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>9</power>
<cooldownTime>1.8</cooldownTime>
<commonality>1.5</commonality>
<armorPenetration>0.11</armorPenetration>
<linkedBodyPartsGroup>Stock</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelblunt</id>
<label>barrel</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.118</armorPenetration>
<linkedBodyPartsGroup>Barrel</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelpoke</id>
<label>muzzle</label>
<capacities>
<li>Poke</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.086</armorPenetration>
<linkedBodyPartsGroup>Muzzle</linkedBodyPartsGroup>
</li>
</tools>
</ThingDef>
<!-- ==================== MG3 machine gun ==================== -->
<ThingDef ParentName="BaseHumanMakeableGun">
<defName>CE_Gun_MGThree</defName>
<label>MG3</label>
<description>A belt-fed general-purpose machine gun. Lots of firepower but heavy and cumbersome to carry around. Commonly nicknamed "The Pig".</description>
<graphicData>
<texPath>Things/Weapons/M60</texPath>
<graphicClass>Graphic_Single</graphicClass>
</graphicData>
<soundInteract>InteractRifle</soundInteract>
<statBases>
<WorkToMake>40500</WorkToMake>
<SightsEfficiency>1</SightsEfficiency>
<ShotSpread>0.08</ShotSpread>
<SwayFactor>1.51</SwayFactor>
<Bulk>11.05</Bulk>
<Mass>10.50</Mass>
<RangedWeapon_Cooldown>0.56</RangedWeapon_Cooldown>
</statBases>
<costList>
<Steel>85</Steel>
<Component>6</Component>
<Chemfuel>15</Chemfuel>
</costList>
<verbs>
<li Class="CombatExtended.VerbPropertiesCE">
<recoilAmount>1.3</recoilAmount>
<verbClass>CombatExtended.Verb_ShootCE</verbClass>
<hasStandardCommand>true</hasStandardCommand>
<defaultProjectile>Bullet_762x51mmNATO_FMJ</defaultProjectile>
<warmupTime>1.0</warmupTime>
<range>75</range>
<ticksBetweenBurstShots>3</ticksBetweenBurstShots>
<burstShotCount>15</burstShotCount>
<soundCast>ShotMinigun</soundCast>
<soundCastTail>GunTail_Heavy</soundCastTail>
<muzzleFlashScale>9</muzzleFlashScale>
<targetParams>
<canTargetLocations>true</canTargetLocations>
</targetParams>
<recoilPattern>Mounted</recoilPattern>
</li>
</verbs>
<comps>
<li Class="CombatExtended.CompProperties_AmmoUser">
<magazineSize>150</magazineSize>
<reloadTime>9.0</reloadTime>
<ammoSet>AmmoSet_762x51mmNATO</ammoSet>
</li>
<li Class="CombatExtended.CompProperties_FireModes">
<aiUseBurstMode>FALSE</aiUseBurstMode>
<aiAimMode>SuppressFire</aiAimMode>
<aimedBurstShotCount>5</aimedBurstShotCount>
</li>
</comps>
<weaponTags>
<li>CE_MachineGun</li>
</weaponTags>
<recipeMaker>
<researchPrerequisite>PrecisionRifling</researchPrerequisite>
</recipeMaker>
<tools>
<li Class="CombatExtended.ToolCE">
<label>stock</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>9</power>
<cooldownTime>1.8</cooldownTime>
<commonality>1.5</commonality>
<armorPenetration>0.11</armorPenetration>
<linkedBodyPartsGroup>Stock</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelblunt</id>
<label>barrel</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.118</armorPenetration>
<linkedBodyPartsGroup>Barrel</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelpoke</id>
<label>muzzle</label>
<capacities>
<li>Poke</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.086</armorPenetration>
<linkedBodyPartsGroup>Muzzle</linkedBodyPartsGroup>
</li>
</tools>
</ThingDef>
<!-- ==================== 92 ==================== -->
<ThingDef ParentName="BaseHumanMakeableGun">
<defName>CE_Gun_B92FS</defName>
<label>Beretta 92FS</label>
<description>Ancient pistol design. Used to be popular with police forces due to its compact size.</description>
<graphicData>
<texPath>Things/Weapons/FS92</texPath>
<graphicClass>Graphic_Single</graphicClass>
</graphicData>
<soundInteract>InteractAutopistol</soundInteract>
<statBases>
<WorkToMake>7000</WorkToMake>
<SightsEfficiency>0.7</SightsEfficiency>
<ShotSpread>0.15</ShotSpread>
<SwayFactor>0.87</SwayFactor>
<Bulk>1.9</Bulk>
<Mass>1.1</Mass>
<RangedWeapon_Cooldown>0.38</RangedWeapon_Cooldown>
</statBases>
<costList>
<Steel>25</Steel>
<Component>3</Component>
</costList>
<verbs>
<li Class="CombatExtended.VerbPropertiesCE">
<verbClass>CombatExtended.Verb_ShootCE</verbClass>
<hasStandardCommand>true</hasStandardCommand>
<defaultProjectile>Bullet_9x19mmPara_FMJ</defaultProjectile>
<warmupTime>0.6</warmupTime>
<range>15</range>
<soundCast>ShotAutopistol</soundCast>
<soundCastTail>GunTail_Light</soundCastTail>
<muzzleFlashScale>9</muzzleFlashScale>
</li>
</verbs>
<comps>
<li Class="CombatExtended.CompProperties_AmmoUser">
<magazineSize>17</magazineSize>
<reloadTime>3</reloadTime>
<ammoSet>AmmoSet_9x19mmPara</ammoSet>
</li>
<li Class="CombatExtended.CompProperties_FireModes" />
</comps>
<recipeMaker>
<researchPrerequisite>BlowbackOperation</researchPrerequisite>
</recipeMaker>
<weaponTags>
<li>CE_Sidearm</li>
<li>CE_OneHandedWeapon</li>
</weaponTags>
<tools>
<li Class="CombatExtended.ToolCE">
<label>grip</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>8</power>
<cooldownTime>1.6</cooldownTime>
<commonality>1.5</commonality>
<armorPenetration>0.102</armorPenetration>
<linkedBodyPartsGroup>Grip</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelblunt</id>
<label>barrel</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>8</power>
<cooldownTime>1.6</cooldownTime>
<armorPenetration>0.102</armorPenetration>
<linkedBodyPartsGroup>Barrel</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelpoke</id>
<label>muzzle</label>
<capacities>
<li>Poke</li>
</capacities>
<power>8</power>
<cooldownTime>1.6</cooldownTime>
<armorPenetration>0.075</armorPenetration>
<linkedBodyPartsGroup>Muzzle</linkedBodyPartsGroup>
</li>
</tools>
</ThingDef>
<!-- ==================== P90 ==================== -->
<ThingDef ParentName="BaseHumanMakeableGun">
<defName>CE_Pninety</defName>
<label>P90</label>
<description>A uniquely shaped, lightweight carbine designed for close-quarters fighting.</description>
<graphicData>
<texPath>Things/Weapons/P90</texPath>
<graphicClass>Graphic_Single</graphicClass>
</graphicData>
<soundInteract>InteractRifle</soundInteract>
<statBases>
<WorkToMake>15500</WorkToMake>
<SightsEfficiency>1</SightsEfficiency>
<ShotSpread>0.05</ShotSpread>
<SwayFactor>0.70</SwayFactor>
<Bulk>2.50</Bulk>
<Mass>2.70</Mass>
<RangedWeapon_Cooldown>0.25</RangedWeapon_Cooldown>
</statBases>
<costList>
<Steel>30</Steel>
<Component>5</Component>
<Chemfuel>10</Chemfuel>
</costList>
<verbs>
<li Class="CombatExtended.VerbPropertiesCE">
<recoilAmount>0.84</recoilAmount>
<verbClass>CombatExtended.Verb_ShootCE</verbClass>
<hasStandardCommand>true</hasStandardCommand>
<defaultProjectile>Bullet_FN57x28mm_AP</defaultProjectile>
<burstShotCount>8</burstShotCount>
<ticksBetweenBurstShots>4</ticksBetweenBurstShots>
<warmupTime>0.6</warmupTime>
<range>38</range>
<soundCast>ShotHeavySMG</soundCast>
<soundCastTail>GunTail_Heavy</soundCastTail>
<muzzleFlashScale>9</muzzleFlashScale>
</li>
</verbs>
<comps>
<li Class="CombatExtended.CompProperties_AmmoUser">
<magazineSize>50</magazineSize>
<reloadTime>6</reloadTime>
<ammoSet>AmmoSet_FN57x28mm</ammoSet>
</li>
<li Class="CombatExtended.CompProperties_FireModes">
<aimedBurstShotCount>3</aimedBurstShotCount>
</li>
</comps>
<recipeMaker>
<researchPrerequisite>PrecisionRifling</researchPrerequisite>
</recipeMaker>
<tools>
<li Class="CombatExtended.ToolCE">
<label>stock</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>9</power>
<cooldownTime>1.8</cooldownTime>
<commonality>1.5</commonality>
<armorPenetration>0.11</armorPenetration>
<linkedBodyPartsGroup>Stock</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelblunt</id>
<label>barrel</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.118</armorPenetration>
<linkedBodyPartsGroup>Barrel</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelpoke</id>
<label>muzzle</label>
<capacities>
<li>Poke</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.086</armorPenetration>
<linkedBodyPartsGroup>Muzzle</linkedBodyPartsGroup>
</li>
</tools>
</ThingDef>
<!-- ==================== Kar 98K ==================== -->
<ThingDef ParentName="BaseHumanMakeableGun">
<defName>kar98k</defName>
<label>Kar 98K</label>
<description>Ancient bolt-action rifle with a full rifle 8mm round.</description>
<graphicData>
<texPath>Things/Weapons/k98</texPath>
<graphicClass>Graphic_Single</graphicClass>
</graphicData>
<soundInteract>InteractRifle</soundInteract>
<statBases>
<WorkToMake>12000</WorkToMake>
<SightsEfficiency>1</SightsEfficiency>
<ShotSpread>0.02</ShotSpread>
<SwayFactor>1.64</SwayFactor>
<Bulk>10.10</Bulk>
<Mass>4.10</Mass>
<RangedWeapon_Cooldown>1.10</RangedWeapon_Cooldown>
</statBases>
<costList>
<Steel>55</Steel>
<WoodLog>15</WoodLog>
<Component>1</Component>
</costList>
<verbs>
<li Class="CombatExtended.VerbPropertiesCE">
<verbClass>CombatExtended.Verb_ShootCE</verbClass>
<hasStandardCommand>true</hasStandardCommand>
<defaultProjectile>Bullet_792x51mmMauser_FMJ</defaultProjectile>
<warmupTime>1.4</warmupTime>
<range>60</range>
<soundCast>ShotSniperRifle</soundCast>
<soundCastTail>GunTail_Heavy</soundCastTail>
<muzzleFlashScale>9</muzzleFlashScale>
</li>
</verbs>
<comps>
<li Class="CombatExtended.CompProperties_AmmoUser">
<magazineSize>5</magazineSize>
<reloadTime>4</reloadTime>
<ammoSet>AmmoSet_792x51mmMauser</ammoSet>
</li>
<li Class="CombatExtended.CompProperties_FireModes">
<aiUseBurstMode>FALSE</aiUseBurstMode>
<aiAimMode>AimedShot</aiAimMode>
</li>
</comps>
<weaponTags>
<li>CE_AI_Rifle</li>
</weaponTags>
<recipeMaker>
<researchPrerequisite>Gunsmithing</researchPrerequisite>
</recipeMaker>
<tools>
<li Class="CombatExtended.ToolCE">
<label>stock</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>9</power>
<cooldownTime>1.8</cooldownTime>
<commonality>1.5</commonality>
<armorPenetration>0.11</armorPenetration>
<linkedBodyPartsGroup>Stock</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelblunt</id>
<label>barrel</label>
<capacities>
<li>Blunt</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.118</armorPenetration>
<linkedBodyPartsGroup>Barrel</linkedBodyPartsGroup>
</li>
<li Class="CombatExtended.ToolCE">
<id>barrelpoke</id>
<label>muzzle</label>
<capacities>
<li>Poke</li>
</capacities>
<power>10</power>
<cooldownTime>1.9</cooldownTime>
<armorPenetration>0.086</armorPenetration>
<linkedBodyPartsGroup>Muzzle</linkedBodyPartsGroup>
</li>
</tools>
</ThingDef>
EDIT: Also, note that rate of fire is determined by ticksBetweenBurstShots variable and is logarithmic in scaling. Example of input and rounds per minute displayed in the game.
Example table:
1 3600
2 1800
3 1200
4 900
5 720
6 600
7 514
8 450
9 400
For the MG3 I use 3, which gives me 1200 RPM while for the G36 I use 5 which gives me 720 RPM.