SAG MK4 Chassis - 5-Slot with Rear Sight Cutout (CNC Aluminum Free-Float)
- $1 349.00
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Available Options
SAG MK4 Chassis - 5-Slot with Rear Sight Cutout
CNC-Machined Aluminum | Free-Floating Barrel | 1913 Top Monorail | Integrated Gas Tube Upper | Rear Sight Cutout | Reusable
Overview
The MK4 is what you get when the MK1 handguard, an integrated gas tube upper and the MK3 removable rear cover are designed as one assembly. The result is a free-floating barrel inside a tubular handguard and a continuous 1913 top monorail running from the gas block all the way back over the receiver.
The rail has a rear sight cutout, so the factory rear sight stays in place and usable behind an optic. A further 1913 segment sits on the removable rear cover section.
Three platform versions are made: S20131 for AK-pattern, S20191 for Saiga-308 and S20192 for VPO/Molot - select yours above. The chassis is CNC-milled high-strength aluminum alloy and can be removed and reinstalled on another carbine. Full-size carbines built on certain Molot Arms receivers (MA-136-02, MA-136C, MA-136-05) must be fitted in a specialist workshop. If you already own an MK1 handguard, the S20132 upgrade kit gets you to the same place for less.
Select the Correct Platform Version
The MK4 Chassis is produced in three platform-specific variants, each machined for a different receiver geometry. These versions are not interchangeable. Please select the variant matching your platform using the Platform Version selector above:
- AK-Pattern version (SKU SAG-S20131)
- Saiga-308 version (SKU SAG-S20191)
- VPO / Molot version (SKU SAG-S20192)
Already own an MK1 handguard? An upgrade kit (upper + rear cover only) is available as a separate product.
Key Advantages
- Free-floats the barrel - inside a tubular handguard
- 1913 top monorail - gas block to shortened cover, for optics and lighting
- Integrated gas tube upper - MK1 handguard + MK3 rear cover architecture
- Rear sight cutout - retains the factory rear sight
- No removal for cleaning - front rail stays on during field-stripping
- Folding-stock compatible - stock folds fully for transport
- Removable rear cover rail - for magnifier or NV attachment
- Reusable - can be reinstalled on a new carbine
Technical Specifications
| Material | High-Strength Aluminum Alloy (CNC-milled) |
| Product Codes | SAG-S20131 (AK-pattern) / SAG-S20191 (Saiga-308) / SAG-S20192 (VPO·Molot) |
| Architecture | MK1 handguard block + integrated gas tube upper + MK3 removable rear cover |
| Top Rail | 1913-MIL-STD monorail, 5 slots (gas block to shortened cover) |
| Rear Sight | Rear sight cutout - retains factory rear sight |
| Rear Cover Rail | 1913-MIL-STD segment (removable section) |
| Barrel | Free-floating inside tubular handguard |
| Reusable | Can be reinstalled on a new carbine |
Compatibility
Available in three platform-specific variants (select above). See the compatibility filter on this page to confirm fitment for your specific platform.
Important: This chassis is not suitable for self-installation on full-size carbines built on certain Molot Arms AK-pattern receivers (MA-136-02, MA-136C, MA-136-05). For those platforms, installation must be performed in a specialist workshop.
What's in the Box
- (1) SAG MK4 Chassis (selected platform version, complete)
- (1) Mounting Hardware Set
- (1) Installation Manual
Frequently Asked Questions
Free-Float Your Platform, Keep Your Irons
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SAG Specs
General
Mounting & Rails
Recommended
SAG, Sureshot Armament, MK4 Chassis, Chassis, 5-Slot, Rear Sight Cutout, Free-Float, 1913 Rail, Gas Tube Upper, Chassis Systems, Bazalet