these lowers will use a M5 bolt that is 25mm long with 1 M5 washer and the M6 lock washer
so the lower got a bit more material so it should be stronger. does this mean that you ned to modified the pistol grips. no. you can still use the same models I have used a small spacer piece around my M5 bolt but it's something that might not be needed at all really.

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MKII vs MKIISD version

this lower got the same concept of using a metal rod with a OD of 4mm and 26mm long as with the FGC9 SD, and I have seen if done before by others. it’s fair to say that it would limit the potential of that part to break.

the MKIISD version will hide the metal pin and makes it look like a stock MKII
but with this design you can hide the metal part. it’s up to you if you like that look better or not.

LBRY Tags: fgc9; fgc9mki; fgc9mkii; fgc9mkiisd; lower