Great post courtesy of Gremlin.
Gremlin said:The trouble with the ACE stuff is that there are too many options, some of which are better than others, some of which are improvements on others, and there is more than one way to do anyting.
First choose the receiver block for the Sig 556
This is going to be EITHER the AR receiver block (#ARRB) (which has a castle nut and STICKS OUT the back of the receiver):
or the AR COMPACT receiver block (#ARRB-C) (this is the BEST OPTION IMHO, because it is flush):
This is a shot of the ARRB-C on a SIG 556 showing how it screws into the receiver flush:
Next choose your folding mechanism.
Your folding mechanism depends on the kind of stock you are using.
If you are using an ACE stock, then choose one of:
a) the regular folding mechanism (#FSM)
b) regular folding mechanism with sling swivel (#FSM-SMG)
c) the push buton folding mechanism
OTHERWISE If you are using an AR or M4 style stock then choose one of:
a) Folding mechanism with AR interface built in (#FSM-AR):
b) Get the CAR15 stock block (aka 'PIG NOSE, #PN) and a castle nut:
and use it to attach your AR15 stock to any of the folding mechanisms:
The regular folding mechanism (#FSM)
The regular folding mechanism with sling swivel
The push buton folding mechanism
Just my opinion, but I think any M4 type stock looks odd with a folding mechanism...