Sig Sauer MCX Rattler 300 Blackout Caliber Conversion Kit – CALX-MCX-5B-300-TAP


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SigSauer MCX Rattler 300 Blackout Caliber Conversion Kit

The Sig Sauer Caliber X-Change Kit allows for the conversion of your Sig Sauer MCX Rattler from 5.56mm to 300 Blackout. Complete with Barrel & Gas Block Assembly. All NFA rules apply to installation of these upper assemblies to lower receivers and caliber exchange kits to upper receivers. Upper assemblies and caliber exchange kits with barrel lengths less than 16 may only be affixed to lower receivers which (1) are not recorded as a rifle lower by the manufacturer and do not have a stock attached to the lower receiver or (2) registered with the BATFE as a short barreled rifle (SBR)..