Picatinny rail front sight base for Tokyo Marui M870 Breacher airsoft shotgun

Important
This is intended for airsoft purpose only. Do not use it on any sort of firearms.
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Description:
A Picatinny rail base for mounting front sights since the original TM M870 Breacher have no iron sights
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Extra material required:
none
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Extra modification required:
none/reversable
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Step to install:

1. Twist out the end cap of the shell tube.
2. put the rail base through shell tube and barrel.
3. Screw back in shell tube end cap to hold the rail base in place.