| '''Standard barrel''' || 8.9 inches || Muzzle: 3-lug mount || [[Heckler & Koch MP5A3]]<br/>[[Heckler & Koch MP5/10A3]]<br/>[[Heckler & Koch MP5/40A2]] || '''100''' || Original 8.9 inch barrel with 3-lug muzzle mount.
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| '''Short MP5K barrel''' || 4.5 inches || Muzzle: N/A<br/>Underbarrel: Integrated foregrip<br/>May affect weapon category and class<sup>'''[[Maze Customs:Major mods#MP5 weapon categorization|(*)]]''' || [[Heckler & Koch MP5K]] || '''150''' || Installs the MP5K 4.5 inch barrel with no muzzle mounting point and the unique integrated foregrip.<br/>'''Not compatible''' with: '''Surefire 628''' and , '''Quad rails''', and '''ISL-201''' handguards
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| '''MP5 Sound Dampened (MP5SD)''' || 5.7 inches || Muzzle: Integrated silencer || || '''900''' || Installs the MP5SD 5.7 inch integrally suppressed barrel, with matching handguards.
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| '''Long barrel''' || 16.9 inches || Weight +1 tier<br/>Muzzle: 3-lug mount || || '''200''' || Installs a 16.9 inch HK94-style barrel. This long barrel possesses the original 3-lug mount, to retain compatibility.<br/>'''Not compatible''' with: '''ISL-201''' handguards
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| '''Quad rails''' || Lights: 2x Long interface<br/>Underbarrel: Long interface || || '''600''' || Quad-rail handguards to attach the lights, lasers, and underbarrel accessories of your choice.<br/>'''Not compatible''' with: '''Short MP5K barrel'''
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| '''ISL-201''' || Underbarrel: Integrated [[ISL-201 UGL-I]] grenade launcher || || '''800''' || Unique dedicated handguard with integrated ISL-201 40mm grenade launcher.<br/>'''Not compatible''' with: '''Short MP5K barrel''' and '''Long barrel'''
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